diff --git a/lib/oauthlib/__init__.py b/lib/oauthlib/__init__.py
index b625c166..a94cf941 100644
--- a/lib/oauthlib/__init__.py
+++ b/lib/oauthlib/__init__.py
@@ -5,21 +5,30 @@
     A generic, spec-compliant, thorough implementation of the OAuth
     request-signing logic.
 
-    :copyright: (c) 2011 by Idan Gazit.
+    :copyright: (c) 2019 by The OAuthlib Community
     :license: BSD, see LICENSE for details.
 """
-
-__author__ = 'Idan Gazit <idan@gazit.me>'
-__version__ = '1.1.1'
-
-
 import logging
-try:  # Python 2.7+
-    from logging import NullHandler
-except ImportError:
-    class NullHandler(logging.Handler):
+from logging import NullHandler
 
-        def emit(self, record):
-            pass
+__author__ = 'The OAuthlib Community'
+__version__ = '3.1.1'
 
 logging.getLogger('oauthlib').addHandler(NullHandler())
+
+_DEBUG = False
+
+def set_debug(debug_val):
+	"""Set value of debug flag
+	
+    :param debug_val: Value to set. Must be a bool value.
+	"""
+	global _DEBUG
+	_DEBUG = debug_val
+
+def get_debug():
+	"""Get debug mode value. 
+	
+	:return: `True` if debug mode is on, `False` otherwise
+	"""
+	return _DEBUG	
diff --git a/lib/oauthlib/common.py b/lib/oauthlib/common.py
index 6b96de82..b5fbf52e 100644
--- a/lib/oauthlib/common.py
+++ b/lib/oauthlib/common.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.common
 ~~~~~~~~~~~~~~
@@ -6,28 +5,24 @@ oauthlib.common
 This module provides data structures and utilities common
 to all implementations of OAuth.
 """
-from __future__ import absolute_import, unicode_literals
-
 import collections
 import datetime
 import logging
-import random
 import re
-import sys
 import time
+import urllib.parse as urlparse
+from urllib.parse import (
+    quote as _quote, unquote as _unquote, urlencode as _urlencode,
+)
+
+from . import get_debug
 
 try:
-    from urllib import quote as _quote
-    from urllib import unquote as _unquote
-    from urllib import urlencode as _urlencode
+    from secrets import randbits
+    from secrets import SystemRandom
 except ImportError:
-    from urllib.parse import quote as _quote
-    from urllib.parse import unquote as _unquote
-    from urllib.parse import urlencode as _urlencode
-try:
-    import urlparse
-except ImportError:
-    import urllib.parse as urlparse
+    from random import getrandbits as randbits
+    from random import SystemRandom
 
 UNICODE_ASCII_CHARACTER_SET = ('abcdefghijklmnopqrstuvwxyz'
                                'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
@@ -45,23 +40,14 @@ always_safe = ('ABCDEFGHIJKLMNOPQRSTUVWXYZ'
 
 log = logging.getLogger('oauthlib')
 
-PY3 = sys.version_info[0] == 3
-
-if PY3:
-    unicode_type = str
-    bytes_type = bytes
-else:
-    unicode_type = unicode
-    bytes_type = str
-
 
 # 'safe' must be bytes (Python 2.6 requires bytes, other versions allow either)
 def quote(s, safe=b'/'):
-    s = s.encode('utf-8') if isinstance(s, unicode_type) else s
+    s = s.encode('utf-8') if isinstance(s, str) else s
     s = _quote(s, safe)
     # PY3 always returns unicode.  PY2 may return either, depending on whether
     # it had to modify the string.
-    if isinstance(s, bytes_type):
+    if isinstance(s, bytes):
         s = s.decode('utf-8')
     return s
 
@@ -71,7 +57,7 @@ def unquote(s):
     # PY3 always returns unicode.  PY2 seems to always return what you give it,
     # which differs from quote's behavior.  Just to be safe, make sure it is
     # unicode before we return.
-    if isinstance(s, bytes_type):
+    if isinstance(s, bytes):
         s = s.decode('utf-8')
     return s
 
@@ -79,7 +65,7 @@ def unquote(s):
 def urlencode(params):
     utf8_params = encode_params_utf8(params)
     urlencoded = _urlencode(utf8_params)
-    if isinstance(urlencoded, unicode_type):  # PY3 returns unicode
+    if isinstance(urlencoded, str):
         return urlencoded
     else:
         return urlencoded.decode("utf-8")
@@ -92,8 +78,8 @@ def encode_params_utf8(params):
     encoded = []
     for k, v in params:
         encoded.append((
-            k.encode('utf-8') if isinstance(k, unicode_type) else k,
-            v.encode('utf-8') if isinstance(v, unicode_type) else v))
+            k.encode('utf-8') if isinstance(k, str) else k,
+            v.encode('utf-8') if isinstance(v, str) else v))
     return encoded
 
 
@@ -104,12 +90,12 @@ def decode_params_utf8(params):
     decoded = []
     for k, v in params:
         decoded.append((
-            k.decode('utf-8') if isinstance(k, bytes_type) else k,
-            v.decode('utf-8') if isinstance(v, bytes_type) else v))
+            k.decode('utf-8') if isinstance(k, bytes) else k,
+            v.decode('utf-8') if isinstance(v, bytes) else v))
     return decoded
 
 
-urlencoded = set(always_safe) | set('=&;%+~,*@!()/?')
+urlencoded = set(always_safe) | set('=&;:%+~,*@!()/?\'$')
 
 
 def urldecode(query):
@@ -137,22 +123,6 @@ def urldecode(query):
     if INVALID_HEX_PATTERN.search(query):
         raise ValueError('Invalid hex encoding in query string.')
 
-    # We encode to utf-8 prior to parsing because parse_qsl behaves
-    # differently on unicode input in python 2 and 3.
-    # Python 2.7
-    # >>> urlparse.parse_qsl(u'%E5%95%A6%E5%95%A6')
-    # u'\xe5\x95\xa6\xe5\x95\xa6'
-    # Python 2.7, non unicode input gives the same
-    # >>> urlparse.parse_qsl('%E5%95%A6%E5%95%A6')
-    # '\xe5\x95\xa6\xe5\x95\xa6'
-    # but now we can decode it to unicode
-    # >>> urlparse.parse_qsl('%E5%95%A6%E5%95%A6').decode('utf-8')
-    # u'\u5566\u5566'
-    # Python 3.3 however
-    # >>> urllib.parse.parse_qsl(u'%E5%95%A6%E5%95%A6')
-    # u'\u5566\u5566'
-    query = query.encode(
-        'utf-8') if not PY3 and isinstance(query, unicode_type) else query
     # We want to allow queries such as "c2" whereas urlparse.parse_qsl
     # with the strict_parsing flag will not.
     params = urlparse.parse_qsl(query, keep_blank_values=True)
@@ -169,7 +139,7 @@ def extract_params(raw):
     empty list of parameters. Any other input will result in a return
     value of None.
     """
-    if isinstance(raw, bytes_type) or isinstance(raw, unicode_type):
+    if isinstance(raw, (bytes, str)):
         try:
             params = urldecode(raw)
         except ValueError:
@@ -199,10 +169,10 @@ def generate_nonce():
     A random 64-bit number is appended to the epoch timestamp for both
     randomness and to decrease the likelihood of collisions.
 
-    .. _`section 3.2.1`: http://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01#section-3.2.1
-    .. _`section 3.3`: http://tools.ietf.org/html/rfc5849#section-3.3
+    .. _`section 3.2.1`: https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01#section-3.2.1
+    .. _`section 3.3`: https://tools.ietf.org/html/rfc5849#section-3.3
     """
-    return unicode_type(unicode_type(random.getrandbits(64)) + generate_timestamp())
+    return str(str(randbits(64)) + generate_timestamp())
 
 
 def generate_timestamp():
@@ -211,10 +181,10 @@ def generate_timestamp():
     Per `section 3.3`_ of the OAuth 1 RFC 5849 spec.
     Per `section 3.2.1`_ of the MAC Access Authentication spec.
 
-    .. _`section 3.2.1`: http://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01#section-3.2.1
-    .. _`section 3.3`: http://tools.ietf.org/html/rfc5849#section-3.3
+    .. _`section 3.2.1`: https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01#section-3.2.1
+    .. _`section 3.3`: https://tools.ietf.org/html/rfc5849#section-3.3
     """
-    return unicode_type(int(time.time()))
+    return str(int(time.time()))
 
 
 def generate_token(length=30, chars=UNICODE_ASCII_CHARACTER_SET):
@@ -225,7 +195,7 @@ def generate_token(length=30, chars=UNICODE_ASCII_CHARACTER_SET):
     and entropy when generating the random characters is important. Which is
     why SystemRandom is used instead of the default random.choice method.
     """
-    rand = random.SystemRandom()
+    rand = SystemRandom()
     return ''.join(rand.choice(chars) for x in range(length))
 
 
@@ -257,7 +227,7 @@ def generate_client_id(length=30, chars=CLIENT_ID_CHARACTER_SET):
     """Generates an OAuth client_id
 
     OAuth 2 specify the format of client_id in
-    http://tools.ietf.org/html/rfc6749#appendix-A.
+    https://tools.ietf.org/html/rfc6749#appendix-A.
     """
     return generate_token(length, chars)
 
@@ -301,11 +271,11 @@ def safe_string_equals(a, b):
 
 def to_unicode(data, encoding='UTF-8'):
     """Convert a number of different types of objects to unicode."""
-    if isinstance(data, unicode_type):
+    if isinstance(data, str):
         return data
 
-    if isinstance(data, bytes_type):
-        return unicode_type(data, encoding=encoding)
+    if isinstance(data, bytes):
+        return str(data, encoding=encoding)
 
     if hasattr(data, '__iter__'):
         try:
@@ -319,7 +289,7 @@ def to_unicode(data, encoding='UTF-8'):
             # We support 2.6 which lacks dict comprehensions
             if hasattr(data, 'items'):
                 data = data.items()
-            return dict(((to_unicode(k, encoding), to_unicode(v, encoding)) for k, v in data))
+            return {to_unicode(k, encoding): to_unicode(v, encoding) for k, v in data}
 
     return data
 
@@ -331,7 +301,7 @@ class CaseInsensitiveDict(dict):
     proxy = {}
 
     def __init__(self, data):
-        self.proxy = dict((k.lower(), k) for k in data)
+        self.proxy = {k.lower(): k for k in data}
         for k in data:
             self[k] = data[k]
 
@@ -340,22 +310,27 @@ class CaseInsensitiveDict(dict):
 
     def __delitem__(self, k):
         key = self.proxy[k.lower()]
-        super(CaseInsensitiveDict, self).__delitem__(key)
+        super().__delitem__(key)
         del self.proxy[k.lower()]
 
     def __getitem__(self, k):
         key = self.proxy[k.lower()]
-        return super(CaseInsensitiveDict, self).__getitem__(key)
+        return super().__getitem__(key)
 
     def get(self, k, default=None):
         return self[k] if k in self else default
 
     def __setitem__(self, k, v):
-        super(CaseInsensitiveDict, self).__setitem__(k, v)
+        super().__setitem__(k, v)
         self.proxy[k.lower()] = k
 
+    def update(self, *args, **kwargs):
+        super().update(*args, **kwargs)
+        for k in dict(*args, **kwargs):
+            self.proxy[k.lower()] = k
 
-class Request(object):
+
+class Request:
 
     """A malleable representation of a signable HTTP request.
 
@@ -389,6 +364,9 @@ class Request(object):
             "client_id": None,
             "client_secret": None,
             "code": None,
+            "code_challenge": None,
+            "code_challenge_method": None,
+            "code_verifier": None,
             "extra_credentials": None,
             "grant_type": None,
             "redirect_uri": None,
@@ -401,10 +379,21 @@ class Request(object):
             "token": None,
             "user": None,
             "token_type_hint": None,
+
+            # OpenID Connect
+            "response_mode": None,
+            "nonce": None,
+            "display": None,
+            "prompt": None,
+            "claims": None,
+            "max_age": None,
+            "ui_locales": None,
+            "id_token_hint": None,
+            "login_hint": None,
+            "acr_values": None
         }
         self._params.update(dict(urldecode(self.uri_query)))
         self._params.update(dict(self.decoded_body or []))
-        self._params.update(self.headers)
 
     def __getattr__(self, name):
         if name in self._params:
@@ -413,13 +402,15 @@ class Request(object):
             raise AttributeError(name)
 
     def __repr__(self):
+        if not get_debug():
+            return "<oauthlib.Request SANITIZED>"
         body = self.body
         headers = self.headers.copy()
         if body:
-            body = SANITIZE_PATTERN.sub('\1<SANITIZED>', body)
+            body = SANITIZE_PATTERN.sub('\1<SANITIZED>', str(body))
         if 'Authorization' in headers:
             headers['Authorization'] = '<SANITIZED>'
-        return '<oauthlib.Request url="%s", http_method="%s", headers="%s", body="%s">' % (
+        return '<oauthlib.Request url="{}", http_method="{}", headers="{}", body="{}">'.format(
             self.uri, self.http_method, headers, body)
 
     @property
diff --git a/lib/oauthlib/oauth1/__init__.py b/lib/oauthlib/oauth1/__init__.py
index b2bc0f90..07ef4226 100644
--- a/lib/oauthlib/oauth1/__init__.py
+++ b/lib/oauthlib/oauth1/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth1
 ~~~~~~~~~~~~~~
@@ -6,14 +5,24 @@ oauthlib.oauth1
 This module is a wrapper for the most recent implementation of OAuth 1.0 Client
 and Server classes.
 """
-from __future__ import absolute_import, unicode_literals
-
 from .rfc5849 import Client
-from .rfc5849 import SIGNATURE_HMAC, SIGNATURE_RSA, SIGNATURE_PLAINTEXT
+from .rfc5849 import (SIGNATURE_HMAC,
+                      SIGNATURE_HMAC_SHA1,
+                      SIGNATURE_HMAC_SHA256,
+                      SIGNATURE_HMAC_SHA512,
+                      SIGNATURE_RSA,
+                      SIGNATURE_RSA_SHA1,
+                      SIGNATURE_RSA_SHA256,
+                      SIGNATURE_RSA_SHA512,
+                      SIGNATURE_PLAINTEXT)
 from .rfc5849 import SIGNATURE_TYPE_AUTH_HEADER, SIGNATURE_TYPE_QUERY
 from .rfc5849 import SIGNATURE_TYPE_BODY
 from .rfc5849.request_validator import RequestValidator
 from .rfc5849.endpoints import RequestTokenEndpoint, AuthorizationEndpoint
 from .rfc5849.endpoints import AccessTokenEndpoint, ResourceEndpoint
 from .rfc5849.endpoints import SignatureOnlyEndpoint, WebApplicationServer
-from .rfc5849.errors import *
+from .rfc5849.errors import (InsecureTransportError,
+                             InvalidClientError,
+                             InvalidRequestError,
+                             InvalidSignatureMethodError,
+                             OAuth1Error)
diff --git a/lib/oauthlib/oauth1/rfc5849/__init__.py b/lib/oauthlib/oauth1/rfc5849/__init__.py
index 56b8c6f2..c559251f 100644
--- a/lib/oauthlib/oauth1/rfc5849/__init__.py
+++ b/lib/oauthlib/oauth1/rfc5849/__init__.py
@@ -1,36 +1,68 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth1.rfc5849
 ~~~~~~~~~~~~~~
 
 This module is an implementation of various logic needed
 for signing and checking OAuth 1.0 RFC 5849 requests.
+
+It supports all three standard signature methods defined in RFC 5849:
+
+- HMAC-SHA1
+- RSA-SHA1
+- PLAINTEXT
+
+It also supports signature methods that are not defined in RFC 5849. These are
+based on the standard ones but replace SHA-1 with the more secure SHA-256:
+
+- HMAC-SHA256
+- RSA-SHA256
+
 """
-from __future__ import absolute_import, unicode_literals
 import base64
 import hashlib
 import logging
-log = logging.getLogger(__name__)
+import urllib.parse as urlparse
 
-import sys
-try:
-    import urlparse
-except ImportError:
-    import urllib.parse as urlparse
+from oauthlib.common import (
+    Request, generate_nonce, generate_timestamp, to_unicode, urlencode,
+)
 
-if sys.version_info[0] == 3:
-    bytes_type = bytes
-else:
-    bytes_type = str
-
-from oauthlib.common import Request, urlencode, generate_nonce
-from oauthlib.common import generate_timestamp, to_unicode
 from . import parameters, signature
 
-SIGNATURE_HMAC = "HMAC-SHA1"
-SIGNATURE_RSA = "RSA-SHA1"
+log = logging.getLogger(__name__)
+
+# Available signature methods
+#
+# Note: SIGNATURE_HMAC and SIGNATURE_RSA are kept for backward compatibility
+# with previous versions of this library, when it the only HMAC-based and
+# RSA-based signature methods were HMAC-SHA1 and RSA-SHA1. But now that it
+# supports other hashing algorithms besides SHA1, explicitly identifying which
+# hashing algorithm is being used is recommended.
+#
+# Note: if additional values are defined here, don't forget to update the
+# imports in "../__init__.py" so they are available outside this module.
+
+SIGNATURE_HMAC_SHA1 = "HMAC-SHA1"
+SIGNATURE_HMAC_SHA256 = "HMAC-SHA256"
+SIGNATURE_HMAC_SHA512 = "HMAC-SHA512"
+SIGNATURE_HMAC = SIGNATURE_HMAC_SHA1  # deprecated variable for HMAC-SHA1
+
+SIGNATURE_RSA_SHA1 = "RSA-SHA1"
+SIGNATURE_RSA_SHA256 = "RSA-SHA256"
+SIGNATURE_RSA_SHA512 = "RSA-SHA512"
+SIGNATURE_RSA = SIGNATURE_RSA_SHA1  # deprecated variable for RSA-SHA1
+
 SIGNATURE_PLAINTEXT = "PLAINTEXT"
-SIGNATURE_METHODS = (SIGNATURE_HMAC, SIGNATURE_RSA, SIGNATURE_PLAINTEXT)
+
+SIGNATURE_METHODS = (
+    SIGNATURE_HMAC_SHA1,
+    SIGNATURE_HMAC_SHA256,
+    SIGNATURE_HMAC_SHA512,
+    SIGNATURE_RSA_SHA1,
+    SIGNATURE_RSA_SHA256,
+    SIGNATURE_RSA_SHA512,
+    SIGNATURE_PLAINTEXT
+)
 
 SIGNATURE_TYPE_AUTH_HEADER = 'AUTH_HEADER'
 SIGNATURE_TYPE_QUERY = 'QUERY'
@@ -39,12 +71,16 @@ SIGNATURE_TYPE_BODY = 'BODY'
 CONTENT_TYPE_FORM_URLENCODED = 'application/x-www-form-urlencoded'
 
 
-class Client(object):
+class Client:
 
     """A client used to sign OAuth 1.0 RFC 5849 requests."""
     SIGNATURE_METHODS = {
-        SIGNATURE_HMAC: signature.sign_hmac_sha1_with_client,
-        SIGNATURE_RSA: signature.sign_rsa_sha1_with_client,
+        SIGNATURE_HMAC_SHA1: signature.sign_hmac_sha1_with_client,
+        SIGNATURE_HMAC_SHA256: signature.sign_hmac_sha256_with_client,
+        SIGNATURE_HMAC_SHA512: signature.sign_hmac_sha512_with_client,
+        SIGNATURE_RSA_SHA1: signature.sign_rsa_sha1_with_client,
+        SIGNATURE_RSA_SHA256: signature.sign_rsa_sha256_with_client,
+        SIGNATURE_RSA_SHA512: signature.sign_rsa_sha512_with_client,
         SIGNATURE_PLAINTEXT: signature.sign_plaintext_with_client
     }
 
@@ -57,7 +93,7 @@ class Client(object):
                  resource_owner_key=None,
                  resource_owner_secret=None,
                  callback_uri=None,
-                 signature_method=SIGNATURE_HMAC,
+                 signature_method=SIGNATURE_HMAC_SHA1,
                  signature_type=SIGNATURE_TYPE_AUTH_HEADER,
                  rsa_key=None, verifier=None, realm=None,
                  encoding='utf-8', decoding=None,
@@ -105,10 +141,11 @@ class Client(object):
     def __repr__(self):
         attrs = vars(self).copy()
         attrs['client_secret'] = '****' if attrs['client_secret'] else None
+        attrs['rsa_key'] = '****' if attrs['rsa_key'] else None
         attrs[
             'resource_owner_secret'] = '****' if attrs['resource_owner_secret'] else None
-        attribute_str = ', '.join('%s=%s' % (k, v) for k, v in attrs.items())
-        return '<%s %s>' % (self.__class__.__name__, attribute_str)
+        attribute_str = ', '.join('{}={}'.format(k, v) for k, v in attrs.items())
+        return '<{} {}>'.format(self.__class__.__name__, attribute_str)
 
     def get_oauth_signature(self, request):
         """Get an OAuth signature to be used in signing a request
@@ -118,7 +155,7 @@ class Client(object):
         replace any netloc part of the request argument's uri attribute
         value.
 
-        .. _`section 3.4.1.2`: http://tools.ietf.org/html/rfc5849#section-3.4.1.2
+        .. _`section 3.4.1.2`: https://tools.ietf.org/html/rfc5849#section-3.4.1.2
         """
         if self.signature_method == SIGNATURE_PLAINTEXT:
             # fast-path
@@ -131,25 +168,24 @@ class Client(object):
             uri_query=urlparse.urlparse(uri).query,
             body=body,
             headers=headers)
-        log.debug("Collected params: {0}".format(collected_params))
+        log.debug("Collected params: {}".format(collected_params))
 
         normalized_params = signature.normalize_parameters(collected_params)
-        normalized_uri = signature.normalize_base_string_uri(uri,
-                                                             headers.get('Host', None))
-        log.debug("Normalized params: {0}".format(normalized_params))
-        log.debug("Normalized URI: {0}".format(normalized_uri))
+        normalized_uri = signature.base_string_uri(uri, headers.get('Host', None))
+        log.debug("Normalized params: {}".format(normalized_params))
+        log.debug("Normalized URI: {}".format(normalized_uri))
 
-        base_string = signature.construct_base_string(request.http_method,
+        base_string = signature.signature_base_string(request.http_method,
                                                       normalized_uri, normalized_params)
 
-        log.debug("Base signing string: {0}".format(base_string))
+        log.debug("Signing: signature base string: {}".format(base_string))
 
         if self.signature_method not in self.SIGNATURE_METHODS:
             raise ValueError('Invalid signature method.')
 
         sig = self.SIGNATURE_METHODS[self.signature_method](base_string, self)
 
-        log.debug("Signature: {0}".format(sig))
+        log.debug("Signature: {}".format(sig))
         return sig
 
     def get_oauth_params(self, request):
@@ -174,10 +210,12 @@ class Client(object):
             params.append(('oauth_verifier', self.verifier))
 
         # providing body hash for requests other than x-www-form-urlencoded
-        # as described in http://oauth.googlecode.com/svn/spec/ext/body_hash/1.0/oauth-bodyhash.html
+        # as described in https://tools.ietf.org/html/draft-eaton-oauth-bodyhash-00#section-4.1.1
         # 4.1.1. When to include the body hash
         #    *  [...] MUST NOT include an oauth_body_hash parameter on requests with form-encoded request bodies
         #    *  [...] SHOULD include the oauth_body_hash parameter on all other requests.
+        # Note that SHA-1 is vulnerable. The spec acknowledges that in https://tools.ietf.org/html/draft-eaton-oauth-bodyhash-00#section-6.2
+        # At this time, no further effort has been made to replace SHA-1 for the OAuth Request Body Hash extension.
         content_type = request.headers.get('Content-Type', None)
         content_type_eligible = content_type and content_type.find('application/x-www-form-urlencoded') < 0
         if request.body is not None and content_type_eligible:
@@ -278,8 +316,8 @@ class Client(object):
         #       header field set to "application/x-www-form-urlencoded".
         elif not should_have_params and has_params:
             raise ValueError(
-                "Body contains parameters but Content-Type header was {0} "
-                "instead of {1}".format(content_type or "not set",
+                "Body contains parameters but Content-Type header was {} "
+                "instead of {}".format(content_type or "not set",
                                         CONTENT_TYPE_FORM_URLENCODED))
 
         # 3.5.2.  Form-Encoded Body
@@ -296,7 +334,7 @@ class Client(object):
             raise ValueError(
                 'Body signatures may only be used with form-urlencoded content')
 
-        # We amend http://tools.ietf.org/html/rfc5849#section-3.4.1.3.1
+        # We amend https://tools.ietf.org/html/rfc5849#section-3.4.1.3.1
         # with the clause that parameters from body should only be included
         # in non GET or HEAD requests. Extracting the request body parameters
         # and including them in the signature base string would give semantic
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/__init__.py b/lib/oauthlib/oauth1/rfc5849/endpoints/__init__.py
index b16ccba6..9f30389f 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/__init__.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/__init__.py
@@ -1,9 +1,8 @@
-from __future__ import absolute_import
-
+from .access_token import AccessTokenEndpoint
+from .authorization import AuthorizationEndpoint
 from .base import BaseEndpoint
 from .request_token import RequestTokenEndpoint
-from .authorization import AuthorizationEndpoint
-from .access_token import AccessTokenEndpoint
 from .resource import ResourceEndpoint
 from .signature_only import SignatureOnlyEndpoint
-from .pre_configured import WebApplicationServer
+
+from .pre_configured import WebApplicationServer  # isort:skip
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/access_token.py b/lib/oauthlib/oauth1/rfc5849/endpoints/access_token.py
index 567965ac..13665db0 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/access_token.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/access_token.py
@@ -8,14 +8,12 @@ OAuth 1.0 RFC 5849. It validates the correctness of access token requests,
 creates and persists tokens as well as create the proper response to be
 returned to the client.
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
 from oauthlib.common import urlencode
 
-from .base import BaseEndpoint
 from .. import errors
+from .base import BaseEndpoint
 
 log = logging.getLogger(__name__)
 
@@ -37,7 +35,8 @@ class AccessTokenEndpoint(BaseEndpoint):
         Similar to OAuth 2, indication of granted scopes will be included as a
         space separated list in ``oauth_authorized_realms``.
 
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The token as an urlencoded string.
         """
         request.realms = self.request_validator.get_realms(
@@ -120,7 +119,8 @@ class AccessTokenEndpoint(BaseEndpoint):
     def validate_access_token_request(self, request):
         """Validate an access token request.
 
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :raises: OAuth1Error if the request is invalid.
         :returns: A tuple of 2 elements.
                   1. The validation result (True or False).
@@ -180,7 +180,7 @@ class AccessTokenEndpoint(BaseEndpoint):
         # token credentials to the client, and ensure that the temporary
         # credentials have not expired or been used before.  The server MUST
         # also verify the verification code received from the client.
-        # .. _`Section 3.2`: http://tools.ietf.org/html/rfc5849#section-3.2
+        # .. _`Section 3.2`: https://tools.ietf.org/html/rfc5849#section-3.2
         #
         # Note that early exit would enable resource owner authorization
         # verifier enumertion.
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/authorization.py b/lib/oauthlib/oauth1/rfc5849/endpoints/authorization.py
index a93a5171..00d9576b 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/authorization.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/authorization.py
@@ -6,16 +6,12 @@ oauthlib.oauth1.rfc5849.endpoints.authorization
 This module is an implementation of various logic needed
 for signing and checking OAuth 1.0 RFC 5849 requests.
 """
-from __future__ import absolute_import, unicode_literals
+from urllib.parse import urlencode
 
-from oauthlib.common import Request, add_params_to_uri
+from oauthlib.common import add_params_to_uri
 
-from .base import BaseEndpoint
 from .. import errors
-try:
-    from urllib import urlencode
-except ImportError:
-    from urllib.parse import urlencode
+from .base import BaseEndpoint
 
 
 class AuthorizationEndpoint(BaseEndpoint):
@@ -41,7 +37,8 @@ class AuthorizationEndpoint(BaseEndpoint):
     def create_verifier(self, request, credentials):
         """Create and save a new request token.
 
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :param credentials: A dict of extra token credentials.
         :returns: The verifier as a dict.
         """
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/base.py b/lib/oauthlib/oauth1/rfc5849/endpoints/base.py
index 42d93634..3a8c2677 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/base.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/base.py
@@ -6,21 +6,20 @@ oauthlib.oauth1.rfc5849.endpoints.base
 This module is an implementation of various logic needed
 for signing and checking OAuth 1.0 RFC 5849 requests.
 """
-from __future__ import absolute_import, unicode_literals
-
 import time
 
-from oauthlib.common import Request, generate_token
+from oauthlib.common import CaseInsensitiveDict, Request, generate_token
 
-from .. import signature, utils, errors
-from .. import CONTENT_TYPE_FORM_URLENCODED
-from .. import SIGNATURE_HMAC, SIGNATURE_RSA
-from .. import SIGNATURE_TYPE_AUTH_HEADER
-from .. import SIGNATURE_TYPE_QUERY
-from .. import SIGNATURE_TYPE_BODY
+from .. import (
+    CONTENT_TYPE_FORM_URLENCODED,
+    SIGNATURE_HMAC_SHA1, SIGNATURE_HMAC_SHA256, SIGNATURE_HMAC_SHA512,
+    SIGNATURE_RSA_SHA1, SIGNATURE_RSA_SHA256, SIGNATURE_RSA_SHA512,
+    SIGNATURE_PLAINTEXT,
+    SIGNATURE_TYPE_AUTH_HEADER, SIGNATURE_TYPE_BODY,
+    SIGNATURE_TYPE_QUERY, errors, signature, utils)
 
 
-class BaseEndpoint(object):
+class BaseEndpoint:
 
     def __init__(self, request_validator, token_generator=None):
         self.request_validator = request_validator
@@ -70,7 +69,7 @@ class BaseEndpoint(object):
 
     def _create_request(self, uri, http_method, body, headers):
         # Only include body data from x-www-form-urlencoded requests
-        headers = headers or {}
+        headers = CaseInsensitiveDict(headers or {})
         if ("Content-Type" in headers and
                 CONTENT_TYPE_FORM_URLENCODED in headers["Content-Type"]):
             request = Request(uri, http_method, body, headers)
@@ -130,11 +129,11 @@ class BaseEndpoint(object):
         # specification.  Implementers should review the Security
         # Considerations section (`Section 4`_) before deciding on which
         # method to support.
-        # .. _`Section 4`: http://tools.ietf.org/html/rfc5849#section-4
+        # .. _`Section 4`: https://tools.ietf.org/html/rfc5849#section-4
         if (not request.signature_method in
                 self.request_validator.allowed_signature_methods):
             raise errors.InvalidSignatureMethodError(
-                description="Invalid signature, %s not in %r." % (
+                description="Invalid signature, {} not in {!r}.".format(
                     request.signature_method,
                     self.request_validator.allowed_signature_methods))
 
@@ -182,35 +181,65 @@ class BaseEndpoint(object):
 
     def _check_signature(self, request, is_token_request=False):
         # ---- RSA Signature verification ----
-        if request.signature_method == SIGNATURE_RSA:
+        if request.signature_method == SIGNATURE_RSA_SHA1 or \
+           request.signature_method == SIGNATURE_RSA_SHA256 or \
+           request.signature_method == SIGNATURE_RSA_SHA512:
+            # RSA-based signature method
+
             # The server verifies the signature per `[RFC3447] section 8.2.2`_
-            # .. _`[RFC3447] section 8.2.2`: http://tools.ietf.org/html/rfc3447#section-8.2.1
+            # .. _`[RFC3447] section 8.2.2`: https://tools.ietf.org/html/rfc3447#section-8.2.1
+
             rsa_key = self.request_validator.get_rsa_key(
                 request.client_key, request)
-            valid_signature = signature.verify_rsa_sha1(request, rsa_key)
+
+            if request.signature_method == SIGNATURE_RSA_SHA1:
+                valid_signature = signature.verify_rsa_sha1(request, rsa_key)
+            elif request.signature_method == SIGNATURE_RSA_SHA256:
+                valid_signature = signature.verify_rsa_sha256(request, rsa_key)
+            elif request.signature_method == SIGNATURE_RSA_SHA512:
+                valid_signature = signature.verify_rsa_sha512(request, rsa_key)
+            else:
+                valid_signature = False
 
         # ---- HMAC or Plaintext Signature verification ----
         else:
+            # Non-RSA based signature method
+
             # Servers receiving an authenticated request MUST validate it by:
             #   Recalculating the request signature independently as described in
             #   `Section 3.4`_ and comparing it to the value received from the
             #   client via the "oauth_signature" parameter.
-            # .. _`Section 3.4`: http://tools.ietf.org/html/rfc5849#section-3.4
+            # .. _`Section 3.4`: https://tools.ietf.org/html/rfc5849#section-3.4
+
             client_secret = self.request_validator.get_client_secret(
                 request.client_key, request)
+
             resource_owner_secret = None
             if request.resource_owner_key:
                 if is_token_request:
-                    resource_owner_secret = self.request_validator.get_request_token_secret(
-                        request.client_key, request.resource_owner_key, request)
+                    resource_owner_secret = \
+                        self.request_validator.get_request_token_secret(
+                            request.client_key, request.resource_owner_key,
+                            request)
                 else:
-                    resource_owner_secret = self.request_validator.get_access_token_secret(
-                        request.client_key, request.resource_owner_key, request)
+                    resource_owner_secret = \
+                        self.request_validator.get_access_token_secret(
+                            request.client_key, request.resource_owner_key,
+                            request)
 
-            if request.signature_method == SIGNATURE_HMAC:
-                valid_signature = signature.verify_hmac_sha1(request,
-                                                             client_secret, resource_owner_secret)
+            if request.signature_method == SIGNATURE_HMAC_SHA1:
+                valid_signature = signature.verify_hmac_sha1(
+                    request, client_secret, resource_owner_secret)
+            elif request.signature_method == SIGNATURE_HMAC_SHA256:
+                valid_signature = signature.verify_hmac_sha256(
+                    request, client_secret, resource_owner_secret)
+            elif request.signature_method == SIGNATURE_HMAC_SHA512:
+                valid_signature = signature.verify_hmac_sha512(
+                    request, client_secret, resource_owner_secret)
+            elif request.signature_method == SIGNATURE_PLAINTEXT:
+                valid_signature = signature.verify_plaintext(
+                    request, client_secret, resource_owner_secret)
             else:
-                valid_signature = signature.verify_plaintext(request,
-                                                             client_secret, resource_owner_secret)
+                valid_signature = False
+
         return valid_signature
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/pre_configured.py b/lib/oauthlib/oauth1/rfc5849/endpoints/pre_configured.py
index f0705a81..23e3cfc8 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/pre_configured.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/pre_configured.py
@@ -1,7 +1,7 @@
-from __future__ import absolute_import, unicode_literals
-
-from . import RequestTokenEndpoint, AuthorizationEndpoint
-from . import AccessTokenEndpoint, ResourceEndpoint
+from . import (
+    AccessTokenEndpoint, AuthorizationEndpoint, RequestTokenEndpoint,
+    ResourceEndpoint,
+)
 
 
 class WebApplicationServer(RequestTokenEndpoint, AuthorizationEndpoint,
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/request_token.py b/lib/oauthlib/oauth1/rfc5849/endpoints/request_token.py
index 4a76abc0..bb67e71e 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/request_token.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/request_token.py
@@ -8,14 +8,12 @@ OAuth 1.0 RFC 5849. It validates the correctness of request token requests,
 creates and persists tokens as well as create the proper response to be
 returned to the client.
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
 from oauthlib.common import urlencode
 
-from .base import BaseEndpoint
 from .. import errors
+from .base import BaseEndpoint
 
 log = logging.getLogger(__name__)
 
@@ -34,7 +32,8 @@ class RequestTokenEndpoint(BaseEndpoint):
     def create_request_token(self, request, credentials):
         """Create and save a new request token.
 
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :param credentials: A dict of extra token credentials.
         :returns: The token as an urlencoded string.
         """
@@ -111,7 +110,8 @@ class RequestTokenEndpoint(BaseEndpoint):
     def validate_request_token_request(self, request):
         """Validate a request token request.
 
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :raises: OAuth1Error if the request is invalid.
         :returns: A tuple of 2 elements.
                   1. The validation result (True or False).
@@ -127,7 +127,7 @@ class RequestTokenEndpoint(BaseEndpoint):
                 request.client_key, request)
         if not self.request_validator.check_realms(request.realms):
             raise errors.InvalidRequestError(
-                description='Invalid realm %s. Allowed are %r.' % (
+                description='Invalid realm {}. Allowed are {!r}.'.format(
                     request.realms, self.request_validator.realms))
 
         if not request.redirect_uri:
@@ -156,7 +156,7 @@ class RequestTokenEndpoint(BaseEndpoint):
         # However they could be seen as a scope or realm to which the
         # client has access and as such every client should be checked
         # to ensure it is authorized access to that scope or realm.
-        # .. _`realm`: http://tools.ietf.org/html/rfc2617#section-1.2
+        # .. _`realm`: https://tools.ietf.org/html/rfc2617#section-1.2
         #
         # Note that early exit would enable client realm access enumeration.
         #
@@ -178,7 +178,7 @@ class RequestTokenEndpoint(BaseEndpoint):
 
         # Callback is normally never required, except for requests for
         # a Temporary Credential as described in `Section 2.1`_
-        # .._`Section 2.1`: http://tools.ietf.org/html/rfc5849#section-2.1
+        # .._`Section 2.1`: https://tools.ietf.org/html/rfc5849#section-2.1
         valid_redirect = self.request_validator.validate_redirect_uri(
             request.client_key, request.redirect_uri, request)
         if not request.redirect_uri:
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/resource.py b/lib/oauthlib/oauth1/rfc5849/endpoints/resource.py
index 60216276..45bdaaac 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/resource.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/resource.py
@@ -6,12 +6,10 @@ oauthlib.oauth1.rfc5849.endpoints.resource
 This module is an implementation of the resource protection provider logic of
 OAuth 1.0 RFC 5849.
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
-from .base import BaseEndpoint
 from .. import errors
+from .base import BaseEndpoint
 
 log = logging.getLogger(__name__)
 
@@ -119,7 +117,7 @@ class ResourceEndpoint(BaseEndpoint):
         # However they could be seen as a scope or realm to which the
         # client has access and as such every client should be checked
         # to ensure it is authorized access to that scope or realm.
-        # .. _`realm`: http://tools.ietf.org/html/rfc2617#section-1.2
+        # .. _`realm`: https://tools.ietf.org/html/rfc2617#section-1.2
         #
         # Note that early exit would enable client realm access enumeration.
         #
diff --git a/lib/oauthlib/oauth1/rfc5849/endpoints/signature_only.py b/lib/oauthlib/oauth1/rfc5849/endpoints/signature_only.py
index d609b7cb..d693ccb7 100644
--- a/lib/oauthlib/oauth1/rfc5849/endpoints/signature_only.py
+++ b/lib/oauthlib/oauth1/rfc5849/endpoints/signature_only.py
@@ -6,12 +6,10 @@ oauthlib.oauth1.rfc5849.endpoints.signature_only
 This module is an implementation of the signing logic of OAuth 1.0 RFC 5849.
 """
 
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
-from .base import BaseEndpoint
 from .. import errors
+from .base import BaseEndpoint
 
 log = logging.getLogger(__name__)
 
@@ -34,17 +32,22 @@ class SignatureOnlyEndpoint(BaseEndpoint):
         """
         try:
             request = self._create_request(uri, http_method, body, headers)
-        except errors.OAuth1Error:
+        except errors.OAuth1Error as err:
+            log.info(
+                'Exception caught while validating request, %s.' % err)
             return False, None
 
         try:
             self._check_transport_security(request)
             self._check_mandatory_parameters(request)
-        except errors.OAuth1Error:
+        except errors.OAuth1Error as err:
+            log.info(
+                'Exception caught while validating request, %s.' % err)
             return False, request
 
         if not self.request_validator.validate_timestamp_and_nonce(
                 request.client_key, request.timestamp, request.nonce, request):
+            log.debug('[Failure] verification failed: timestamp/nonce')
             return False, request
 
         # The server SHOULD return a 401 (Unauthorized) status code when
diff --git a/lib/oauthlib/oauth1/rfc5849/errors.py b/lib/oauthlib/oauth1/rfc5849/errors.py
index 978035ed..8774d407 100644
--- a/lib/oauthlib/oauth1/rfc5849/errors.py
+++ b/lib/oauthlib/oauth1/rfc5849/errors.py
@@ -1,4 +1,3 @@
-# coding=utf-8
 """
 oauthlib.oauth1.rfc5849.errors
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,9 +5,7 @@ oauthlib.oauth1.rfc5849.errors
 Error used both by OAuth 1 clients and provicers to represent the spec
 defined error responses for all four core grant types.
 """
-from __future__ import unicode_literals
-
-from oauthlib.common import urlencode, add_params_to_uri
+from oauthlib.common import add_params_to_uri, urlencode
 
 
 class OAuth1Error(Exception):
@@ -37,10 +34,10 @@ class OAuth1Error(Exception):
         request:  Oauthlib Request object
         """
         self.description = description or self.description
-        message = '(%s) %s' % (self.error, self.description)
+        message = '({}) {}'.format(self.error, self.description)
         if request:
             message += ' ' + repr(request)
-        super(OAuth1Error, self).__init__(message)
+        super().__init__(message)
 
         self.uri = uri
         self.status_code = status_code
diff --git a/lib/oauthlib/oauth1/rfc5849/parameters.py b/lib/oauthlib/oauth1/rfc5849/parameters.py
index f0963aba..2163772d 100644
--- a/lib/oauthlib/oauth1/rfc5849/parameters.py
+++ b/lib/oauthlib/oauth1/rfc5849/parameters.py
@@ -1,21 +1,17 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.parameters
 ~~~~~~~~~~~~~~~~~~~
 
 This module contains methods related to `section 3.5`_ of the OAuth 1.0a spec.
 
-.. _`section 3.5`: http://tools.ietf.org/html/rfc5849#section-3.5
+.. _`section 3.5`: https://tools.ietf.org/html/rfc5849#section-3.5
 """
-from __future__ import absolute_import, unicode_literals
+from urllib.parse import urlparse, urlunparse
 
-try:
-    from urlparse import urlparse, urlunparse
-except ImportError:
-    from urllib.parse import urlparse, urlunparse
-from . import utils
 from oauthlib.common import extract_params, urlencode
 
+from . import utils
+
 
 # TODO: do we need filter_params now that oauth_params are handled by Request?
 #       We can easily pass in just oauth protocol params.
@@ -40,8 +36,8 @@ def prepare_headers(oauth_params, headers=None, realm=None):
             oauth_version="1.0"
 
 
-    .. _`section 3.5.1`: http://tools.ietf.org/html/rfc5849#section-3.5.1
-    .. _`RFC2617`: http://tools.ietf.org/html/rfc2617
+    .. _`section 3.5.1`: https://tools.ietf.org/html/rfc5849#section-3.5.1
+    .. _`RFC2617`: https://tools.ietf.org/html/rfc2617
     """
     headers = headers or {}
 
@@ -52,28 +48,28 @@ def prepare_headers(oauth_params, headers=None, realm=None):
         # 1.  Parameter names and values are encoded per Parameter Encoding
         #     (`Section 3.6`_)
         #
-        # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+        # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
         escaped_name = utils.escape(oauth_parameter_name)
         escaped_value = utils.escape(value)
 
         # 2.  Each parameter's name is immediately followed by an "=" character
         #     (ASCII code 61), a """ character (ASCII code 34), the parameter
         #     value (MAY be empty), and another """ character (ASCII code 34).
-        part = '{0}="{1}"'.format(escaped_name, escaped_value)
+        part = '{}="{}"'.format(escaped_name, escaped_value)
 
         authorization_header_parameters_parts.append(part)
 
     # 3.  Parameters are separated by a "," character (ASCII code 44) and
     #     OPTIONAL linear whitespace per `RFC2617`_.
     #
-    # .. _`RFC2617`: http://tools.ietf.org/html/rfc2617
+    # .. _`RFC2617`: https://tools.ietf.org/html/rfc2617
     authorization_header_parameters = ', '.join(
         authorization_header_parameters_parts)
 
     # 4.  The OPTIONAL "realm" parameter MAY be added and interpreted per
     #     `RFC2617 section 1.2`_.
     #
-    # .. _`RFC2617 section 1.2`: http://tools.ietf.org/html/rfc2617#section-1.2
+    # .. _`RFC2617 section 1.2`: https://tools.ietf.org/html/rfc2617#section-1.2
     if realm:
         # NOTE: realm should *not* be escaped
         authorization_header_parameters = ('realm="%s", ' % realm +
@@ -96,8 +92,8 @@ def _append_params(oauth_params, params):
 
     Per `section 3.5.2`_ and `3.5.3`_ of the spec.
 
-    .. _`section 3.5.2`: http://tools.ietf.org/html/rfc5849#section-3.5.2
-    .. _`3.5.3`: http://tools.ietf.org/html/rfc5849#section-3.5.3
+    .. _`section 3.5.2`: https://tools.ietf.org/html/rfc5849#section-3.5.2
+    .. _`3.5.3`: https://tools.ietf.org/html/rfc5849#section-3.5.3
 
     """
     merged = list(params)
@@ -115,7 +111,7 @@ def prepare_form_encoded_body(oauth_params, body):
 
     Per `section 3.5.2`_ of the spec.
 
-    .. _`section 3.5.2`: http://tools.ietf.org/html/rfc5849#section-3.5.2
+    .. _`section 3.5.2`: https://tools.ietf.org/html/rfc5849#section-3.5.2
 
     """
     # append OAuth params to the existing body
@@ -127,7 +123,7 @@ def prepare_request_uri_query(oauth_params, uri):
 
     Per `section 3.5.3`_ of the spec.
 
-    .. _`section 3.5.3`: http://tools.ietf.org/html/rfc5849#section-3.5.3
+    .. _`section 3.5.3`: https://tools.ietf.org/html/rfc5849#section-3.5.3
 
     """
     # append OAuth params to the existing set of query components
diff --git a/lib/oauthlib/oauth1/rfc5849/request_validator.py b/lib/oauthlib/oauth1/rfc5849/request_validator.py
index 30a36948..dc5bf0eb 100644
--- a/lib/oauthlib/oauth1/rfc5849/request_validator.py
+++ b/lib/oauthlib/oauth1/rfc5849/request_validator.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth1.rfc5849
 ~~~~~~~~~~~~~~
@@ -6,12 +5,10 @@ oauthlib.oauth1.rfc5849
 This module is an implementation of various logic needed
 for signing and checking OAuth 1.0 RFC 5849 requests.
 """
-from __future__ import absolute_import, unicode_literals
-
 from . import SIGNATURE_METHODS, utils
 
 
-class RequestValidator(object):
+class RequestValidator:
 
     """A validator/datastore interaction base class for OAuth 1 providers.
 
@@ -107,7 +104,7 @@ class RequestValidator(object):
     their use more straightforward and as such it could be worth reading what
     follows in chronological order.
 
-    .. _`whitelisting or blacklisting`: http://www.schneier.com/blog/archives/2011/01/whitelisting_vs.html
+    .. _`whitelisting or blacklisting`: https://www.schneier.com/blog/archives/2011/01/whitelisting_vs.html
     """
 
     def __init__(self):
@@ -195,7 +192,15 @@ class RequestValidator(object):
 
     def check_realms(self, realms):
         """Check that the realm is one of a set allowed realms."""
-        return all((r in self.realms for r in realms))
+        return all(r in self.realms for r in realms)
+
+    def _subclass_must_implement(self, fn):
+        """
+        Returns a NotImplementedError for a function that should be implemented.
+        :param fn: name of the function
+        """
+        m = "Missing function implementation in {}: {}".format(type(self), fn)
+        return NotImplementedError(m)
 
     @property
     def dummy_client(self):
@@ -219,7 +224,7 @@ class RequestValidator(object):
         * ResourceEndpoint
         * SignatureOnlyEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("dummy_client")
 
     @property
     def dummy_request_token(self):
@@ -235,7 +240,7 @@ class RequestValidator(object):
 
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("dummy_request_token")
 
     @property
     def dummy_access_token(self):
@@ -251,13 +256,14 @@ class RequestValidator(object):
 
         * ResourceEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("dummy_access_token")
 
     def get_client_secret(self, client_key, request):
         """Retrieves the client secret associated with the client key.
 
         :param client_key: The client/consumer key.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The client secret as a string.
 
         This method must allow the use of a dummy client_key value.
@@ -286,14 +292,15 @@ class RequestValidator(object):
         * ResourceEndpoint
         * SignatureOnlyEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement('get_client_secret')
 
     def get_request_token_secret(self, client_key, token, request):
         """Retrieves the shared secret associated with the request token.
 
         :param client_key: The client/consumer key.
         :param token: The request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The token secret as a string.
 
         This method must allow the use of a dummy values and the running time
@@ -318,14 +325,15 @@ class RequestValidator(object):
 
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement('get_request_token_secret')
 
     def get_access_token_secret(self, client_key, token, request):
         """Retrieves the shared secret associated with the access token.
 
         :param client_key: The client/consumer key.
         :param token: The access token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The token secret as a string.
 
         This method must allow the use of a dummy values and the running time
@@ -350,13 +358,14 @@ class RequestValidator(object):
 
         * ResourceEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("get_access_token_secret")
 
     def get_default_realms(self, client_key, request):
         """Get the default realms for a client.
 
         :param client_key: The client/consumer key.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The list of default realms associated with the client.
 
         The list of default realms will be set during client registration and
@@ -366,13 +375,14 @@ class RequestValidator(object):
 
         * RequestTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("get_default_realms")
 
     def get_realms(self, token, request):
         """Get realms associated with a request token.
 
         :param token: The request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The list of realms associated with the request token.
 
         This method is used by
@@ -380,13 +390,14 @@ class RequestValidator(object):
         * AuthorizationEndpoint
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("get_realms")
 
     def get_redirect_uri(self, token, request):
         """Get the redirect URI associated with a request token.
 
         :param token: The request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The redirect URI associated with the request token.
 
         It may be desirable to return a custom URI if the redirect is set to "oob".
@@ -397,13 +408,14 @@ class RequestValidator(object):
 
         * AuthorizationEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("get_redirect_uri")
 
     def get_rsa_key(self, client_key, request):
         """Retrieves a previously stored client provided RSA key.
 
         :param client_key: The client/consumer key.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: The rsa public key as a string.
 
         This method must allow the use of a dummy client_key value. Fetching
@@ -420,14 +432,15 @@ class RequestValidator(object):
         * ResourceEndpoint
         * SignatureOnlyEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("get_rsa_key")
 
     def invalidate_request_token(self, client_key, request_token, request):
         """Invalidates a used request token.
 
         :param client_key: The client/consumer key.
         :param request_token: The request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: None
 
         Per `Section 2.3`__ of the spec:
@@ -435,7 +448,7 @@ class RequestValidator(object):
         "The server MUST (...) ensure that the temporary
         credentials have not expired or been used before."
 
-        .. _`Section 2.3`: http://tools.ietf.org/html/rfc5849#section-2.3
+        .. _`Section 2.3`: https://tools.ietf.org/html/rfc5849#section-2.3
 
         This method should ensure that provided token won't validate anymore.
         It can be simply removing RequestToken from storage or setting
@@ -446,13 +459,14 @@ class RequestValidator(object):
 
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("invalidate_request_token")
 
     def validate_client_key(self, client_key, request):
         """Validates that supplied client key is a registered and valid client.
 
         :param client_key: The client/consumer key.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         Note that if the dummy client is supplied it should validate in same
@@ -482,14 +496,15 @@ class RequestValidator(object):
         * ResourceEndpoint
         * SignatureOnlyEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_client_key")
 
     def validate_request_token(self, client_key, token, request):
         """Validates that supplied request token is registered and valid.
 
         :param client_key: The client/consumer key.
         :param token: The request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         Note that if the dummy request_token is supplied it should validate in
@@ -516,14 +531,15 @@ class RequestValidator(object):
 
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_request_token")
 
     def validate_access_token(self, client_key, token, request):
         """Validates that supplied access token is registered and valid.
 
         :param client_key: The client/consumer key.
         :param token: The access token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         Note that if the dummy access token is supplied it should validate in
@@ -550,7 +566,7 @@ class RequestValidator(object):
 
         * ResourceEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_access_token")
 
     def validate_timestamp_and_nonce(self, client_key, timestamp, nonce,
                                      request, request_token=None, access_token=None):
@@ -561,7 +577,8 @@ class RequestValidator(object):
         :param nonce: The ``oauth_nonce`` parameter.
         :param request_token: Request token string, if any.
         :param access_token: Access token string, if any.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         Per `Section 3.3`_ of the spec.
@@ -572,7 +589,7 @@ class RequestValidator(object):
         channel.  The nonce value MUST be unique across all requests with the
         same timestamp, client credentials, and token combinations."
 
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc5849#section-3.3
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc5849#section-3.3
 
         One of the first validation checks that will be made is for the validity
         of the nonce and timestamp, which are associated with a client key and
@@ -600,7 +617,7 @@ class RequestValidator(object):
         * ResourceEndpoint
         * SignatureOnlyEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_timestamp_and_nonce")
 
     def validate_redirect_uri(self, client_key, redirect_uri, request):
         """Validates the client supplied redirection URI.
@@ -608,7 +625,8 @@ class RequestValidator(object):
         :param client_key: The client/consumer key.
         :param redirect_uri: The URI the client which to redirect back to after
                              authorization is successful.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         It is highly recommended that OAuth providers require their clients
@@ -633,14 +651,15 @@ class RequestValidator(object):
 
         * RequestTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_redirect_uri")
 
     def validate_requested_realms(self, client_key, realms, request):
         """Validates that the client may request access to the realm.
 
         :param client_key: The client/consumer key.
         :param realms: The list of realms that client is requesting access to.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         This method is invoked when obtaining a request token and should
@@ -651,7 +670,7 @@ class RequestValidator(object):
 
         * RequestTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_requested_realms")
 
     def validate_realms(self, client_key, token, request, uri=None,
                         realms=None):
@@ -659,7 +678,8 @@ class RequestValidator(object):
 
         :param client_key: The client/consumer key.
         :param token: A request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :param uri: The URI the realms is protecting.
         :param realms: A list of realms that must have been granted to
                        the access token.
@@ -685,7 +705,7 @@ class RequestValidator(object):
 
         * ResourceEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_realms")
 
     def validate_verifier(self, client_key, token, verifier, request):
         """Validates a verification code.
@@ -693,7 +713,8 @@ class RequestValidator(object):
         :param client_key: The client/consumer key.
         :param token: A request token string.
         :param verifier: The authorization verifier string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         OAuth providers issue a verification code to clients after the
@@ -716,13 +737,14 @@ class RequestValidator(object):
 
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("validate_verifier")
 
     def verify_request_token(self, token, request):
         """Verify that the given OAuth1 request token is valid.
 
         :param token: A request token string.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         This method is used only in AuthorizationEndpoint to check whether the
@@ -734,14 +756,15 @@ class RequestValidator(object):
 
         * AuthorizationEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("verify_request_token")
 
     def verify_realms(self, token, realms, request):
         """Verify authorized realms to see if they match those given to token.
 
         :param token: An access token string.
         :param realms: A list of realms the client attempts to access.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :returns: True or False
 
         This prevents the list of authorized realms sent by the client during
@@ -757,13 +780,14 @@ class RequestValidator(object):
 
         * AuthorizationEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("verify_realms")
 
     def save_access_token(self, token, request):
         """Save an OAuth1 access token.
 
         :param token: A dict with token credentials.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         The token dictionary will at minimum include
 
@@ -780,13 +804,14 @@ class RequestValidator(object):
 
         * AccessTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("save_access_token")
 
     def save_request_token(self, token, request):
         """Save an OAuth1 request token.
 
         :param token: A dict with token credentials.
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         The token dictionary will at minimum include
 
@@ -800,7 +825,7 @@ class RequestValidator(object):
 
         * RequestTokenEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("save_request_token")
 
     def save_verifier(self, token, verifier, request):
         """Associate an authorization verifier with a request token.
@@ -808,7 +833,8 @@ class RequestValidator(object):
         :param token: A request token string.
         :param verifier A dictionary containing the oauth_verifier and
                         oauth_token
-        :param request: An oauthlib.common.Request object.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         We need to associate verifiers with tokens for validation during the
         access token request.
@@ -820,4 +846,4 @@ class RequestValidator(object):
 
         * AuthorizationEndpoint
         """
-        raise NotImplementedError("Subclasses must implement this function.")
+        raise self._subclass_must_implement("save_verifier")
diff --git a/lib/oauthlib/oauth1/rfc5849/signature.py b/lib/oauthlib/oauth1/rfc5849/signature.py
index 8fa22baf..a370ccd6 100644
--- a/lib/oauthlib/oauth1/rfc5849/signature.py
+++ b/lib/oauthlib/oauth1/rfc5849/signature.py
@@ -1,70 +1,72 @@
-# -*- coding: utf-8 -*-
 """
-oauthlib.oauth1.rfc5849.signature
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+This module is an implementation of `section 3.4`_ of RFC 5849.
 
-This module represents a direct implementation of `section 3.4`_ of the spec.
-
-Terminology:
- * Client: software interfacing with an OAuth API
- * Server: the API provider
- * Resource Owner: the user who is granting authorization to the client
+**Usage**
 
 Steps for signing a request:
 
-1. Collect parameters from the uri query, auth header, & body
-2. Normalize those parameters
-3. Normalize the uri
-4. Pass the normalized uri, normalized parameters, and http method to
-   construct the base string
-5. Pass the base string and any keys needed to a signing function
+1. Collect parameters from the request using ``collect_parameters``.
+2. Normalize those parameters using ``normalize_parameters``.
+3. Create the *base string URI* using ``base_string_uri``.
+4. Create the *signature base string* from the above three components
+   using ``signature_base_string``.
+5. Pass the *signature base string* and the client credentials to one of the
+   sign-with-client functions. The HMAC-based signing functions needs
+   client credentials with secrets. The RSA-based signing functions needs
+   client credentials with an RSA private key.
 
-.. _`section 3.4`: http://tools.ietf.org/html/rfc5849#section-3.4
+To verify a request, pass the request and credentials to one of the verify
+functions. The HMAC-based signing functions needs the shared secrets. The
+RSA-based verify functions needs the RSA public key.
+
+**Scope**
+
+All of the functions in this module should be considered internal to OAuthLib,
+since they are not imported into the "oauthlib.oauth1" module. Programs using
+OAuthLib should not use directly invoke any of the functions in this module.
+
+**Deprecated functions**
+
+The "sign_" methods that are not "_with_client" have been deprecated. They may
+be removed in a future release. Since they are all internal functions, this
+should have no impact on properly behaving programs.
+
+.. _`section 3.4`: https://tools.ietf.org/html/rfc5849#section-3.4
 """
-from __future__ import absolute_import, unicode_literals
 
 import binascii
 import hashlib
 import hmac
-try:
-    import urlparse
-except ImportError:
-    import urllib.parse as urlparse
+import logging
+import warnings
+
+from oauthlib.common import extract_params, safe_string_equals, urldecode
+import urllib.parse as urlparse
+
 from . import utils
-from oauthlib.common import urldecode, extract_params, safe_string_equals
-from oauthlib.common import bytes_type, unicode_type
 
 
-def construct_base_string(http_method, base_string_uri,
-                          normalized_encoded_request_parameters):
-    """**String Construction**
-    Per `section 3.4.1.1`_ of the spec.
+log = logging.getLogger(__name__)
 
-    For example, the HTTP request::
 
-        POST /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b HTTP/1.1
-        Host: example.com
-        Content-Type: application/x-www-form-urlencoded
-        Authorization: OAuth realm="Example",
-            oauth_consumer_key="9djdj82h48djs9d2",
-            oauth_token="kkk9d7dh3k39sjv7",
-            oauth_signature_method="HMAC-SHA1",
-            oauth_timestamp="137131201",
-            oauth_nonce="7d8f3e4a",
-            oauth_signature="bYT5CMsGcbgUdFHObYMEfcx6bsw%3D"
+# ==== Common functions ==========================================
 
-        c2&a3=2+q
+def signature_base_string(
+        http_method: str,
+        base_str_uri: str,
+        normalized_encoded_request_parameters: str) -> str:
+    """
+    Construct the signature base string.
 
-    is represented by the following signature base string (line breaks
-    are for display purposes only)::
+    The *signature base string* is the value that is calculated and signed by
+    the client. It is also independently calculated by the server to verify
+    the signature, and therefore must produce the exact same value at both
+    ends or the signature won't verify.
 
-        POST&http%3A%2F%2Fexample.com%2Frequest&a2%3Dr%2520b%26a3%3D2%2520q
-        %26a3%3Da%26b5%3D%253D%25253D%26c%2540%3D%26c2%3D%26oauth_consumer_
-        key%3D9djdj82h48djs9d2%26oauth_nonce%3D7d8f3e4a%26oauth_signature_m
-        ethod%3DHMAC-SHA1%26oauth_timestamp%3D137131201%26oauth_token%3Dkkk
-        9d7dh3k39sjv7
+    The rules for calculating the *signature base string* are defined in
+    section 3.4.1.1`_ of RFC 5849.
 
-    .. _`section 3.4.1.1`: http://tools.ietf.org/html/rfc5849#section-3.4.1.1
+    .. _`section 3.4.1.1`: https://tools.ietf.org/html/rfc5849#section-3.4.1.1
     """
 
     # The signature base string is constructed by concatenating together,
@@ -74,7 +76,7 @@ def construct_base_string(http_method, base_string_uri,
     #     "GET", "POST", etc.  If the request uses a custom HTTP method, it
     #     MUST be encoded (`Section 3.6`_).
     #
-    # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     base_string = utils.escape(http_method.upper())
 
     # 2.  An "&" character (ASCII code 38).
@@ -83,9 +85,9 @@ def construct_base_string(http_method, base_string_uri,
     # 3.  The base string URI from `Section 3.4.1.2`_, after being encoded
     #     (`Section 3.6`_).
     #
-    # .. _`Section 3.4.1.2`: http://tools.ietf.org/html/rfc5849#section-3.4.1.2
-    # .. _`Section 3.4.6`: http://tools.ietf.org/html/rfc5849#section-3.4.6
-    base_string += utils.escape(base_string_uri)
+    # .. _`Section 3.4.1.2`: https://tools.ietf.org/html/rfc5849#section-3.4.1.2
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
+    base_string += utils.escape(base_str_uri)
 
     # 4.  An "&" character (ASCII code 38).
     base_string += '&'
@@ -93,37 +95,40 @@ def construct_base_string(http_method, base_string_uri,
     # 5.  The request parameters as normalized in `Section 3.4.1.3.2`_, after
     #     being encoded (`Section 3.6`).
     #
-    # .. _`Section 3.4.1.3.2`: http://tools.ietf.org/html/rfc5849#section-3.4.1.3.2
-    # .. _`Section 3.4.6`: http://tools.ietf.org/html/rfc5849#section-3.4.6
+    # .. _`Sec 3.4.1.3.2`: https://tools.ietf.org/html/rfc5849#section-3.4.1.3.2
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     base_string += utils.escape(normalized_encoded_request_parameters)
 
     return base_string
 
 
-def normalize_base_string_uri(uri, host=None):
-    """**Base String URI**
-    Per `section 3.4.1.2`_ of the spec.
-
-    For example, the HTTP request::
-
-        GET /r%20v/X?id=123 HTTP/1.1
-        Host: EXAMPLE.COM:80
-
-    is represented by the base string URI: "http://example.com/r%20v/X".
-
-    In another example, the HTTPS request::
-
-        GET /?q=1 HTTP/1.1
-        Host: www.example.net:8080
-
-    is represented by the base string URI: "https://www.example.net:8080/".
-
-    .. _`section 3.4.1.2`: http://tools.ietf.org/html/rfc5849#section-3.4.1.2
-
-    The host argument overrides the netloc part of the uri argument.
+def base_string_uri(uri: str, host: str = None) -> str:
     """
-    if not isinstance(uri, unicode_type):
-        raise ValueError('uri must be a unicode object.')
+    Calculates the _base string URI_.
+
+    The *base string URI* is one of the components that make up the
+     *signature base string*.
+
+    The ``host`` is optional. If provided, it is used to override any host and
+    port values in the ``uri``. The value for ``host`` is usually extracted from
+    the "Host" request header from the HTTP request. Its value may be just the
+    hostname, or the hostname followed by a colon and a TCP/IP port number
+    (hostname:port). If a value for the``host`` is provided but it does not
+    contain a port number, the default port number is used (i.e. if the ``uri``
+    contained a port number, it will be discarded).
+
+    The rules for calculating the *base string URI* are defined in
+    section 3.4.1.2`_ of RFC 5849.
+
+    .. _`section 3.4.1.2`: https://tools.ietf.org/html/rfc5849#section-3.4.1.2
+
+    :param uri: URI
+    :param host: hostname with optional port number, separated by a colon
+    :return: base string URI
+    """
+
+    if not isinstance(uri, str):
+        raise ValueError('uri must be a string.')
 
     # FIXME: urlparse does not support unicode
     scheme, netloc, path, params, query, fragment = urlparse.urlparse(uri)
@@ -132,28 +137,29 @@ def normalize_base_string_uri(uri, host=None):
     # are included by constructing an "http" or "https" URI representing
     # the request resource (without the query or fragment) as follows:
     #
-    # .. _`RFC3986`: http://tools.ietf.org/html/rfc3986
+    # .. _`RFC3986`: https://tools.ietf.org/html/rfc3986
 
-    if not scheme or not netloc:
-        raise ValueError('uri must include a scheme and netloc')
+    if not scheme:
+        raise ValueError('missing scheme')
 
     # Per `RFC 2616 section 5.1.2`_:
     #
     # Note that the absolute path cannot be empty; if none is present in
     # the original URI, it MUST be given as "/" (the server root).
     #
-    # .. _`RFC 2616 section 5.1.2`: http://tools.ietf.org/html/rfc2616#section-5.1.2
+    # .. _`RFC 2616 5.1.2`: https://tools.ietf.org/html/rfc2616#section-5.1.2
     if not path:
         path = '/'
 
     # 1.  The scheme and host MUST be in lowercase.
     scheme = scheme.lower()
     netloc = netloc.lower()
+    # Note: if ``host`` is used, it will be converted to lowercase below
 
     # 2.  The host and port values MUST match the content of the HTTP
     #     request "Host" header field.
     if host is not None:
-        netloc = host.lower()
+        netloc = host.lower()  # override value in uri with provided host
 
     # 3.  The port MUST be included if it is not the default port for the
     #     scheme, and MUST be excluded if it is the default.  Specifically,
@@ -161,91 +167,87 @@ def normalize_base_string_uri(uri, host=None):
     #     to port 80 or when making an HTTPS request `RFC2818`_ to port 443.
     #     All other non-default port numbers MUST be included.
     #
-    # .. _`RFC2616`: http://tools.ietf.org/html/rfc2616
-    # .. _`RFC2818`: http://tools.ietf.org/html/rfc2818
-    default_ports = (
-        ('http', '80'),
-        ('https', '443'),
-    )
+    # .. _`RFC2616`: https://tools.ietf.org/html/rfc2616
+    # .. _`RFC2818`: https://tools.ietf.org/html/rfc2818
+
     if ':' in netloc:
-        host, port = netloc.split(':', 1)
-        if (scheme, port) in default_ports:
-            netloc = host
+        # Contains a colon ":", so try to parse as "host:port"
 
-    return urlparse.urlunparse((scheme, netloc, path, params, '', ''))
+        hostname, port_str = netloc.split(':', 1)
+
+        if len(hostname) == 0:
+            raise ValueError('missing host')  # error: netloc was ":port" or ":"
+
+        if len(port_str) == 0:
+            netloc = hostname  # was "host:", so just use the host part
+        else:
+            try:
+                port_num = int(port_str)  # try to parse into an integer number
+            except ValueError:
+                raise ValueError('port is not an integer')
+
+            if port_num <= 0 or 65535 < port_num:
+                raise ValueError('port out of range')  # 16-bit unsigned ints
+            if (scheme, port_num) in (('http', 80), ('https', 443)):
+                netloc = hostname  # default port for scheme: exclude port num
+            else:
+                netloc = hostname + ':' + str(port_num)  # use hostname:port
+    else:
+        # Does not contain a colon, so entire value must be the hostname
+
+        if len(netloc) == 0:
+            raise ValueError('missing host')  # error: netloc was empty string
+
+    v = urlparse.urlunparse((scheme, netloc, path, params, '', ''))
+
+    # RFC 5849 does not specify which characters are encoded in the
+    # "base string URI", nor how they are encoded - which is very bad, since
+    # the signatures won't match if there are any differences. Fortunately,
+    # most URIs only use characters that are clearly not encoded (e.g. digits
+    # and A-Z, a-z), so have avoided any differences between implementations.
+    #
+    # The example from its section 3.4.1.2 illustrates that spaces in
+    # the path are percent encoded. But it provides no guidance as to what other
+    # characters (if any) must be encoded (nor how); nor if characters in the
+    # other components are to be encoded or not.
+    #
+    # This implementation **assumes** that **only** the space is percent-encoded
+    # and it is done to the entire value (not just to spaces in the path).
+    #
+    # This code may need to be changed if it is discovered that other characters
+    # are expected to be encoded.
+    #
+    # Note: the "base string URI" returned by this function will be encoded
+    # again before being concatenated into the "signature base string". So any
+    # spaces in the URI will actually appear in the "signature base string"
+    # as "%2520" (the "%20" further encoded according to section 3.6).
+
+    return v.replace(' ', '%20')
 
 
-# ** Request Parameters **
-#
-#    Per `section 3.4.1.3`_ of the spec.
-#
-#    In order to guarantee a consistent and reproducible representation of
-#    the request parameters, the parameters are collected and decoded to
-#    their original decoded form.  They are then sorted and encoded in a
-#    particular manner that is often different from their original
-#    encoding scheme, and concatenated into a single string.
-#
-# .. _`section 3.4.1.3`: http://tools.ietf.org/html/rfc5849#section-3.4.1.3
-
-def collect_parameters(uri_query='', body=[], headers=None,
+def collect_parameters(uri_query='', body=None, headers=None,
                        exclude_oauth_signature=True, with_realm=False):
-    """**Parameter Sources**
+    """
+    Gather the request parameters from all the parameter sources.
+
+    This function is used to extract all the parameters, which are then passed
+    to ``normalize_parameters`` to produce one of the components that make up
+    the *signature base string*.
 
     Parameters starting with `oauth_` will be unescaped.
 
     Body parameters must be supplied as a dict, a list of 2-tuples, or a
-    formencoded query string.
+    form encoded query string.
 
     Headers must be supplied as a dict.
 
-    Per `section 3.4.1.3.1`_ of the spec.
+    The rules where the parameters must be sourced from are defined in
+    `section 3.4.1.3.1`_ of RFC 5849.
 
-    For example, the HTTP request::
-
-        POST /request?b5=%3D%253D&a3=a&c%40=&a2=r%20b HTTP/1.1
-        Host: example.com
-        Content-Type: application/x-www-form-urlencoded
-        Authorization: OAuth realm="Example",
-            oauth_consumer_key="9djdj82h48djs9d2",
-            oauth_token="kkk9d7dh3k39sjv7",
-            oauth_signature_method="HMAC-SHA1",
-            oauth_timestamp="137131201",
-            oauth_nonce="7d8f3e4a",
-            oauth_signature="djosJKDKJSD8743243%2Fjdk33klY%3D"
-
-        c2&a3=2+q
-
-    contains the following (fully decoded) parameters used in the
-    signature base sting::
-
-        +------------------------+------------------+
-        |          Name          |       Value      |
-        +------------------------+------------------+
-        |           b5           |       =%3D       |
-        |           a3           |         a        |
-        |           c@           |                  |
-        |           a2           |        r b       |
-        |   oauth_consumer_key   | 9djdj82h48djs9d2 |
-        |       oauth_token      | kkk9d7dh3k39sjv7 |
-        | oauth_signature_method |     HMAC-SHA1    |
-        |     oauth_timestamp    |     137131201    |
-        |       oauth_nonce      |     7d8f3e4a     |
-        |           c2           |                  |
-        |           a3           |        2 q       |
-        +------------------------+------------------+
-
-    Note that the value of "b5" is "=%3D" and not "==".  Both "c@" and
-    "c2" have empty values.  While the encoding rules specified in this
-    specification for the purpose of constructing the signature base
-    string exclude the use of a "+" character (ASCII code 43) to
-    represent an encoded space character (ASCII code 32), this practice
-    is widely used in "application/x-www-form-urlencoded" encoded values,
-    and MUST be properly decoded, as demonstrated by one of the "a3"
-    parameter instances (the "a3" parameter is used twice in this
-    request).
-
-    .. _`section 3.4.1.3.1`: http://tools.ietf.org/html/rfc5849#section-3.4.1.3.1
+    .. _`Sec 3.4.1.3.1`: https://tools.ietf.org/html/rfc5849#section-3.4.1.3.1
     """
+    if body is None:
+        body = []
     headers = headers or {}
     params = []
 
@@ -256,11 +258,11 @@ def collect_parameters(uri_query='', body=[], headers=None,
     #    `RFC3986, Section 3.4`_.  The query component is parsed into a list
     #    of name/value pairs by treating it as an
     #    "application/x-www-form-urlencoded" string, separating the names
-    #    and values and decoding them as defined by
-    #    `W3C.REC-html40-19980424`_, Section 17.13.4.
+    #    and values and decoding them as defined by W3C.REC-html40-19980424
+    #    `W3C-HTML-4.0`_, Section 17.13.4.
     #
-    # .. _`RFC3986, Section 3.4`: http://tools.ietf.org/html/rfc3986#section-3.4
-    # .. _`W3C.REC-html40-19980424`: http://tools.ietf.org/html/rfc5849#ref-W3C.REC-html40-19980424
+    # .. _`RFC3986, Sec 3.4`: https://tools.ietf.org/html/rfc3986#section-3.4
+    # .. _`W3C-HTML-4.0`: https://www.w3.org/TR/1998/REC-html40-19980424/
     if uri_query:
         params.extend(urldecode(uri_query))
 
@@ -269,9 +271,9 @@ def collect_parameters(uri_query='', body=[], headers=None,
     #    pairs excluding the "realm" parameter if present.  The parameter
     #    values are decoded as defined by `Section 3.5.1`_.
     #
-    # .. _`Section 3.5.1`: http://tools.ietf.org/html/rfc5849#section-3.5.1
+    # .. _`Section 3.5.1`: https://tools.ietf.org/html/rfc5849#section-3.5.1
     if headers:
-        headers_lower = dict((k.lower(), v) for k, v in headers.items())
+        headers_lower = {k.lower(): v for k, v in headers.items()}
         authorization_header = headers_lower.get('authorization')
         if authorization_header is not None:
             params.extend([i for i in utils.parse_authorization_header(
@@ -283,12 +285,12 @@ def collect_parameters(uri_query='', body=[], headers=None,
     #
     #     *  The entity-body follows the encoding requirements of the
     #        "application/x-www-form-urlencoded" content-type as defined by
-    #        `W3C.REC-html40-19980424`_.
+    #        W3C.REC-html40-19980424 `W3C-HTML-4.0`_.
 
     #     *  The HTTP request entity-header includes the "Content-Type"
     #        header field set to "application/x-www-form-urlencoded".
     #
-    # .._`W3C.REC-html40-19980424`: http://tools.ietf.org/html/rfc5849#ref-W3C.REC-html40-19980424
+    # .. _`W3C-HTML-4.0`: https://www.w3.org/TR/1998/REC-html40-19980424/
 
     # TODO: enforce header param inclusion conditions
     bodyparams = extract_params(body) or []
@@ -310,86 +312,28 @@ def collect_parameters(uri_query='', body=[], headers=None,
     return unescaped_params
 
 
-def normalize_parameters(params):
-    """**Parameters Normalization**
-    Per `section 3.4.1.3.2`_ of the spec.
+def normalize_parameters(params) -> str:
+    """
+    Calculate the normalized request parameters.
 
-    For example, the list of parameters from the previous section would
-    be normalized as follows:
+    The *normalized request parameters* is one of the components that make up
+    the *signature base string*.
 
-    Encoded::
+    The rules for parameter normalization are defined in `section 3.4.1.3.2`_ of
+    RFC 5849.
 
-    +------------------------+------------------+
-    |          Name          |       Value      |
-    +------------------------+------------------+
-    |           b5           |     %3D%253D     |
-    |           a3           |         a        |
-    |          c%40          |                  |
-    |           a2           |       r%20b      |
-    |   oauth_consumer_key   | 9djdj82h48djs9d2 |
-    |       oauth_token      | kkk9d7dh3k39sjv7 |
-    | oauth_signature_method |     HMAC-SHA1    |
-    |     oauth_timestamp    |     137131201    |
-    |       oauth_nonce      |     7d8f3e4a     |
-    |           c2           |                  |
-    |           a3           |       2%20q      |
-    +------------------------+------------------+
-
-    Sorted::
-
-    +------------------------+------------------+
-    |          Name          |       Value      |
-    +------------------------+------------------+
-    |           a2           |       r%20b      |
-    |           a3           |       2%20q      |
-    |           a3           |         a        |
-    |           b5           |     %3D%253D     |
-    |          c%40          |                  |
-    |           c2           |                  |
-    |   oauth_consumer_key   | 9djdj82h48djs9d2 |
-    |       oauth_nonce      |     7d8f3e4a     |
-    | oauth_signature_method |     HMAC-SHA1    |
-    |     oauth_timestamp    |     137131201    |
-    |       oauth_token      | kkk9d7dh3k39sjv7 |
-    +------------------------+------------------+
-
-    Concatenated Pairs::
-
-    +-------------------------------------+
-    |              Name=Value             |
-    +-------------------------------------+
-    |               a2=r%20b              |
-    |               a3=2%20q              |
-    |                 a3=a                |
-    |             b5=%3D%253D             |
-    |                c%40=                |
-    |                 c2=                 |
-    | oauth_consumer_key=9djdj82h48djs9d2 |
-    |         oauth_nonce=7d8f3e4a        |
-    |   oauth_signature_method=HMAC-SHA1  |
-    |      oauth_timestamp=137131201      |
-    |     oauth_token=kkk9d7dh3k39sjv7    |
-    +-------------------------------------+
-
-    and concatenated together into a single string (line breaks are for
-    display purposes only)::
-
-        a2=r%20b&a3=2%20q&a3=a&b5=%3D%253D&c%40=&c2=&oauth_consumer_key=9dj
-        dj82h48djs9d2&oauth_nonce=7d8f3e4a&oauth_signature_method=HMAC-SHA1
-        &oauth_timestamp=137131201&oauth_token=kkk9d7dh3k39sjv7
-
-    .. _`section 3.4.1.3.2`: http://tools.ietf.org/html/rfc5849#section-3.4.1.3.2
+    .. _`Sec 3.4.1.3.2`: https://tools.ietf.org/html/rfc5849#section-3.4.1.3.2
     """
 
     # The parameters collected in `Section 3.4.1.3`_ are normalized into a
     # single string as follows:
     #
-    # .. _`Section 3.4.1.3`: http://tools.ietf.org/html/rfc5849#section-3.4.1.3
+    # .. _`Section 3.4.1.3`: https://tools.ietf.org/html/rfc5849#section-3.4.1.3
 
     # 1.  First, the name and value of each parameter are encoded
     #     (`Section 3.6`_).
     #
-    # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     key_values = [(utils.escape(k), utils.escape(v)) for k, v in params]
 
     # 2.  The parameters are sorted by name, using ascending byte value
@@ -400,7 +344,7 @@ def normalize_parameters(params):
     # 3.  The name of each parameter is concatenated to its corresponding
     #     value using an "=" character (ASCII code 61) as a separator, even
     #     if the value is empty.
-    parameter_parts = ['{0}={1}'.format(k, v) for k, v in key_values]
+    parameter_parts = ['{}={}'.format(k, v) for k, v in key_values]
 
     # 4.  The sorted name/value pairs are concatenated together into a
     #     single string by using an "&" character (ASCII code 38) as
@@ -408,39 +352,38 @@ def normalize_parameters(params):
     return '&'.join(parameter_parts)
 
 
-def sign_hmac_sha1_with_client(base_string, client):
-    return sign_hmac_sha1(base_string,
-                          client.client_secret,
-                          client.resource_owner_secret
-                          )
+# ==== Common functions for HMAC-based signature methods =========
 
+def _sign_hmac(hash_algorithm_name: str,
+               sig_base_str: str,
+               client_secret: str,
+               resource_owner_secret: str):
+    """
+    **HMAC-SHA256**
 
-def sign_hmac_sha1(base_string, client_secret, resource_owner_secret):
-    """**HMAC-SHA1**
+    The "HMAC-SHA256" signature method uses the HMAC-SHA256 signature
+    algorithm as defined in `RFC4634`_::
 
-    The "HMAC-SHA1" signature method uses the HMAC-SHA1 signature
-    algorithm as defined in `RFC2104`_::
-
-        digest = HMAC-SHA1 (key, text)
+        digest = HMAC-SHA256 (key, text)
 
     Per `section 3.4.2`_ of the spec.
 
-    .. _`RFC2104`: http://tools.ietf.org/html/rfc2104
-    .. _`section 3.4.2`: http://tools.ietf.org/html/rfc5849#section-3.4.2
+    .. _`RFC4634`: https://tools.ietf.org/html/rfc4634
+    .. _`section 3.4.2`: https://tools.ietf.org/html/rfc5849#section-3.4.2
     """
 
-    # The HMAC-SHA1 function variables are used in following way:
+    # The HMAC-SHA256 function variables are used in following way:
 
     # text is set to the value of the signature base string from
     # `Section 3.4.1.1`_.
     #
-    # .. _`Section 3.4.1.1`: http://tools.ietf.org/html/rfc5849#section-3.4.1.1
-    text = base_string
+    # .. _`Section 3.4.1.1`: https://tools.ietf.org/html/rfc5849#section-3.4.1.1
+    text = sig_base_str
 
     # key is set to the concatenated values of:
     # 1.  The client shared-secret, after being encoded (`Section 3.6`_).
     #
-    # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     key = utils.escape(client_secret or '')
 
     # 2.  An "&" character (ASCII code 38), which MUST be included
@@ -449,60 +392,406 @@ def sign_hmac_sha1(base_string, client_secret, resource_owner_secret):
 
     # 3.  The token shared-secret, after being encoded (`Section 3.6`_).
     #
-    # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     key += utils.escape(resource_owner_secret or '')
 
+    # Get the hashing algorithm to use
+
+    m = {
+        'SHA-1': hashlib.sha1,
+        'SHA-256': hashlib.sha256,
+        'SHA-512': hashlib.sha512,
+    }
+    hash_alg = m[hash_algorithm_name]
+
+    # Calculate the signature
+
     # FIXME: HMAC does not support unicode!
     key_utf8 = key.encode('utf-8')
     text_utf8 = text.encode('utf-8')
-    signature = hmac.new(key_utf8, text_utf8, hashlib.sha1)
+    signature = hmac.new(key_utf8, text_utf8, hash_alg)
 
     # digest  is used to set the value of the "oauth_signature" protocol
     #         parameter, after the result octet string is base64-encoded
     #         per `RFC2045, Section 6.8`.
     #
-    # .. _`RFC2045, Section 6.8`: http://tools.ietf.org/html/rfc2045#section-6.8
+    # .. _`RFC2045, Sec 6.8`: https://tools.ietf.org/html/rfc2045#section-6.8
     return binascii.b2a_base64(signature.digest())[:-1].decode('utf-8')
 
-_jwtrs1 = None
 
-#jwt has some nice pycrypto/cryptography abstractions
-def _jwt_rs1_signing_algorithm():
-    global _jwtrs1
-    if _jwtrs1 is None:
-        import jwt.algorithms as jwtalgo
-        _jwtrs1 = jwtalgo.RSAAlgorithm(jwtalgo.hashes.SHA1)
-    return _jwtrs1
+def _verify_hmac(hash_algorithm_name: str,
+                 request,
+                 client_secret=None,
+                 resource_owner_secret=None):
+    """Verify a HMAC-SHA1 signature.
 
-def sign_rsa_sha1(base_string, rsa_private_key):
-    """**RSA-SHA1**
+    Per `section 3.4`_ of the spec.
 
-    Per `section 3.4.3`_ of the spec.
+    .. _`section 3.4`: https://tools.ietf.org/html/rfc5849#section-3.4
 
-    The "RSA-SHA1" signature method uses the RSASSA-PKCS1-v1_5 signature
-    algorithm as defined in `RFC3447, Section 8.2`_ (also known as
-    PKCS#1), using SHA-1 as the hash function for EMSA-PKCS1-v1_5.  To
+    To satisfy `RFC2616 section 5.2`_ item 1, the request argument's uri
+    attribute MUST be an absolute URI whose netloc part identifies the
+    origin server or gateway on which the resource resides. Any Host
+    item of the request argument's headers dict attribute will be
+    ignored.
+
+    .. _`RFC2616 section 5.2`: https://tools.ietf.org/html/rfc2616#section-5.2
+
+    """
+    norm_params = normalize_parameters(request.params)
+    bs_uri = base_string_uri(request.uri)
+    sig_base_str = signature_base_string(request.http_method, bs_uri,
+                                         norm_params)
+    signature = _sign_hmac(hash_algorithm_name, sig_base_str,
+                           client_secret, resource_owner_secret)
+    match = safe_string_equals(signature, request.signature)
+    if not match:
+        log.debug('Verify HMAC failed: signature base string: %s', sig_base_str)
+    return match
+
+
+# ==== HMAC-SHA1 =================================================
+
+def sign_hmac_sha1_with_client(sig_base_str, client):
+    return _sign_hmac('SHA-1', sig_base_str,
+                      client.client_secret, client.resource_owner_secret)
+
+
+def verify_hmac_sha1(request, client_secret=None, resource_owner_secret=None):
+    return _verify_hmac('SHA-1', request, client_secret, resource_owner_secret)
+
+
+def sign_hmac_sha1(base_string, client_secret, resource_owner_secret):
+    """
+    Deprecated function for calculating a HMAC-SHA1 signature.
+
+    This function has been replaced by invoking ``sign_hmac`` with "SHA-1"
+    as the hash algorithm name.
+
+    This function was invoked by sign_hmac_sha1_with_client and
+    test_signatures.py, but does any application invoke it directly? If not,
+    it can be removed.
+    """
+    warnings.warn('use sign_hmac_sha1_with_client instead of sign_hmac_sha1',
+                  DeprecationWarning)
+
+    # For some unknown reason, the original implementation assumed base_string
+    # could either be bytes or str. The signature base string calculating
+    # function always returned a str, so the new ``sign_rsa`` only expects that.
+
+    base_string = base_string.decode('ascii') \
+        if isinstance(base_string, bytes) else base_string
+
+    return _sign_hmac('SHA-1', base_string,
+                      client_secret, resource_owner_secret)
+
+
+# ==== HMAC-SHA256 ===============================================
+
+def sign_hmac_sha256_with_client(sig_base_str, client):
+    return _sign_hmac('SHA-256', sig_base_str,
+                      client.client_secret, client.resource_owner_secret)
+
+
+def verify_hmac_sha256(request, client_secret=None, resource_owner_secret=None):
+    return _verify_hmac('SHA-256', request,
+                        client_secret, resource_owner_secret)
+
+
+def sign_hmac_sha256(base_string, client_secret, resource_owner_secret):
+    """
+    Deprecated function for calculating a HMAC-SHA256 signature.
+
+    This function has been replaced by invoking ``sign_hmac`` with "SHA-256"
+    as the hash algorithm name.
+
+    This function was invoked by sign_hmac_sha256_with_client and
+    test_signatures.py, but does any application invoke it directly? If not,
+    it can be removed.
+    """
+    warnings.warn(
+        'use sign_hmac_sha256_with_client instead of sign_hmac_sha256',
+        DeprecationWarning)
+
+    # For some unknown reason, the original implementation assumed base_string
+    # could either be bytes or str. The signature base string calculating
+    # function always returned a str, so the new ``sign_rsa`` only expects that.
+
+    base_string = base_string.decode('ascii') \
+        if isinstance(base_string, bytes) else base_string
+
+    return _sign_hmac('SHA-256', base_string,
+                      client_secret, resource_owner_secret)
+
+
+# ==== HMAC-SHA512 ===============================================
+
+def sign_hmac_sha512_with_client(sig_base_str: str,
+                                 client):
+    return _sign_hmac('SHA-512', sig_base_str,
+                      client.client_secret, client.resource_owner_secret)
+
+
+def verify_hmac_sha512(request,
+                       client_secret: str = None,
+                       resource_owner_secret: str = None):
+    return _verify_hmac('SHA-512', request,
+                        client_secret, resource_owner_secret)
+
+
+# ==== Common functions for RSA-based signature methods ==========
+
+_jwt_rsa = {}  # cache of RSA-hash implementations from PyJWT jwt.algorithms
+
+
+def _get_jwt_rsa_algorithm(hash_algorithm_name: str):
+    """
+    Obtains an RSAAlgorithm object that implements RSA with the hash algorithm.
+
+    This method maintains the ``_jwt_rsa`` cache.
+
+    Returns a jwt.algorithm.RSAAlgorithm.
+    """
+    if hash_algorithm_name in _jwt_rsa:
+        # Found in cache: return it
+        return _jwt_rsa[hash_algorithm_name]
+    else:
+        # Not in cache: instantiate a new RSAAlgorithm
+
+        # PyJWT has some nice pycrypto/cryptography abstractions
+        import jwt.algorithms as jwt_algorithms
+        m = {
+            'SHA-1': jwt_algorithms.hashes.SHA1,
+            'SHA-256': jwt_algorithms.hashes.SHA256,
+            'SHA-512': jwt_algorithms.hashes.SHA512,
+        }
+        v = jwt_algorithms.RSAAlgorithm(m[hash_algorithm_name])
+
+        _jwt_rsa[hash_algorithm_name] = v  # populate cache
+
+        return v
+
+
+def _prepare_key_plus(alg, keystr):
+    """
+    Prepare a PEM encoded key (public or private), by invoking the `prepare_key`
+    method on alg with the keystr.
+
+    The keystr should be a string or bytes.  If the keystr is bytes, it is
+    decoded as UTF-8 before being passed to prepare_key. Otherwise, it
+    is passed directly.
+    """
+    if isinstance(keystr, bytes):
+        keystr = keystr.decode('utf-8')
+    return alg.prepare_key(keystr)
+
+
+def _sign_rsa(hash_algorithm_name: str,
+              sig_base_str: str,
+              rsa_private_key: str):
+    """
+    Calculate the signature for an RSA-based signature method.
+
+    The ``alg`` is used to calculate the digest over the signature base string.
+    For the "RSA_SHA1" signature method, the alg must be SHA-1. While OAuth 1.0a
+    only defines the RSA-SHA1 signature method, this function can be used for
+    other non-standard signature methods that only differ from RSA-SHA1 by the
+    digest algorithm.
+
+    Signing for the RSA-SHA1 signature method is defined in
+    `section 3.4.3`_ of RFC 5849.
+
+    The RSASSA-PKCS1-v1_5 signature algorithm used defined by
+    `RFC3447, Section 8.2`_ (also known as PKCS#1), with the `alg` as the
+    hash function for EMSA-PKCS1-v1_5.  To
     use this method, the client MUST have established client credentials
     with the server that included its RSA public key (in a manner that is
     beyond the scope of this specification).
 
-    .. _`section 3.4.3`: http://tools.ietf.org/html/rfc5849#section-3.4.3
-    .. _`RFC3447, Section 8.2`: http://tools.ietf.org/html/rfc3447#section-8.2
-
+    .. _`section 3.4.3`: https://tools.ietf.org/html/rfc5849#section-3.4.3
+    .. _`RFC3447, Section 8.2`: https://tools.ietf.org/html/rfc3447#section-8.2
     """
-    if isinstance(base_string, unicode_type):
-        base_string = base_string.encode('utf-8')
-    # TODO: finish RSA documentation
-    alg = _jwt_rs1_signing_algorithm()
+
+    # Get the implementation of RSA-hash
+
+    alg = _get_jwt_rsa_algorithm(hash_algorithm_name)
+
+    # Check private key
+
+    if not rsa_private_key:
+        raise ValueError('rsa_private_key required for RSA with ' +
+                         alg.hash_alg.name + ' signature method')
+
+    # Convert the "signature base string" into a sequence of bytes (M)
+    #
+    # The signature base string, by definition, only contain printable US-ASCII
+    # characters. So encoding it as 'ascii' will always work. It will raise a
+    # ``UnicodeError`` if it can't encode the value, which will never happen
+    # if the signature base string was created correctly. Therefore, using
+    # 'ascii' encoding provides an extra level of error checking.
+
+    m = sig_base_str.encode('ascii')
+
+    # Perform signing: S = RSASSA-PKCS1-V1_5-SIGN (K, M)
+
     key = _prepare_key_plus(alg, rsa_private_key)
-    s=alg.sign(base_string, key)
-    return binascii.b2a_base64(s)[:-1].decode('utf-8')
+    s = alg.sign(m, key)
+
+    # base64-encoded per RFC2045 section 6.8.
+    #
+    # 1. While b2a_base64 implements base64 defined by RFC 3548. As used here,
+    #    it is the same as base64 defined by RFC 2045.
+    # 2. b2a_base64 includes a "\n" at the end of its result ([:-1] removes it)
+    # 3. b2a_base64 produces a binary string. Use decode to produce a str.
+    #    It should only contain only printable US-ASCII characters.
+
+    return binascii.b2a_base64(s)[:-1].decode('ascii')
 
 
-def sign_rsa_sha1_with_client(base_string, client):
-    if not client.rsa_key:
-        raise ValueError('rsa_key is required when using RSA signature method.')
-    return sign_rsa_sha1(base_string, client.rsa_key)
+def _verify_rsa(hash_algorithm_name: str,
+                request,
+                rsa_public_key: str):
+    """
+    Verify a base64 encoded signature for a RSA-based signature method.
+
+    The ``alg`` is used to calculate the digest over the signature base string.
+    For the "RSA_SHA1" signature method, the alg must be SHA-1. While OAuth 1.0a
+    only defines the RSA-SHA1 signature method, this function can be used for
+    other non-standard signature methods that only differ from RSA-SHA1 by the
+    digest algorithm.
+
+    Verification for the RSA-SHA1 signature method is defined in
+    `section 3.4.3`_ of RFC 5849.
+
+    .. _`section 3.4.3`: https://tools.ietf.org/html/rfc5849#section-3.4.3
+
+        To satisfy `RFC2616 section 5.2`_ item 1, the request argument's uri
+        attribute MUST be an absolute URI whose netloc part identifies the
+        origin server or gateway on which the resource resides. Any Host
+        item of the request argument's headers dict attribute will be
+        ignored.
+
+        .. _`RFC2616 Sec 5.2`: https://tools.ietf.org/html/rfc2616#section-5.2
+    """
+
+    try:
+        # Calculate the *signature base string* of the actual received request
+
+        norm_params = normalize_parameters(request.params)
+        bs_uri = base_string_uri(request.uri)
+        sig_base_str = signature_base_string(
+            request.http_method, bs_uri, norm_params)
+
+        # Obtain the signature that was received in the request
+
+        sig = binascii.a2b_base64(request.signature.encode('ascii'))
+
+        # Get the implementation of RSA-with-hash algorithm to use
+
+        alg = _get_jwt_rsa_algorithm(hash_algorithm_name)
+
+        # Verify the received signature was produced by the private key
+        # corresponding to the `rsa_public_key`, signing exact same
+        # *signature base string*.
+        #
+        #     RSASSA-PKCS1-V1_5-VERIFY ((n, e), M, S)
+
+        key = _prepare_key_plus(alg, rsa_public_key)
+
+        # The signature base string only contain printable US-ASCII characters.
+        # The ``encode`` method with the default "strict" error handling will
+        # raise a ``UnicodeError`` if it can't encode the value. So using
+        # "ascii" will always work.
+
+        verify_ok = alg.verify(sig_base_str.encode('ascii'), key, sig)
+
+        if not verify_ok:
+            log.debug('Verify failed: RSA with ' + alg.hash_alg.name +
+                      ': signature base string=%s' + sig_base_str)
+        return verify_ok
+
+    except UnicodeError:
+        # A properly encoded signature will only contain printable US-ASCII
+        # characters. The ``encode`` method with the default "strict" error
+        # handling will raise a ``UnicodeError`` if it can't decode the value.
+        # So using "ascii" will work with all valid signatures. But an
+        # incorrectly or maliciously produced signature could contain other
+        # bytes.
+        #
+        # This implementation treats that situation as equivalent to the
+        # signature verification having failed.
+        #
+        # Note: simply changing the encode to use 'utf-8' will not remove this
+        # case, since an incorrect or malicious request can contain bytes which
+        # are invalid as UTF-8.
+        return False
+
+
+# ==== RSA-SHA1 ==================================================
+
+def sign_rsa_sha1_with_client(sig_base_str, client):
+    # For some reason, this function originally accepts both str and bytes.
+    # This behaviour is preserved here. But won't be done for the newer
+    # sign_rsa_sha256_with_client and sign_rsa_sha512_with_client functions,
+    # which will only accept strings. The function to calculate a
+    # "signature base string" always produces a string, so it is not clear
+    # why support for bytes would ever be needed.
+    sig_base_str = sig_base_str.decode('ascii')\
+        if isinstance(sig_base_str, bytes) else sig_base_str
+
+    return _sign_rsa('SHA-1', sig_base_str, client.rsa_key)
+
+
+def verify_rsa_sha1(request, rsa_public_key: str):
+    return _verify_rsa('SHA-1', request, rsa_public_key)
+
+
+def sign_rsa_sha1(base_string, rsa_private_key):
+    """
+    Deprecated function for calculating a RSA-SHA1 signature.
+
+    This function has been replaced by invoking ``sign_rsa`` with "SHA-1"
+    as the hash algorithm name.
+
+    This function was invoked by sign_rsa_sha1_with_client and
+    test_signatures.py, but does any application invoke it directly? If not,
+    it can be removed.
+    """
+    warnings.warn('use _sign_rsa("SHA-1", ...) instead of sign_rsa_sha1',
+                  DeprecationWarning)
+
+    if isinstance(base_string, bytes):
+        base_string = base_string.decode('ascii')
+
+    return _sign_rsa('SHA-1', base_string, rsa_private_key)
+
+
+# ==== RSA-SHA256 ================================================
+
+def sign_rsa_sha256_with_client(sig_base_str: str, client):
+    return _sign_rsa('SHA-256', sig_base_str, client.rsa_key)
+
+
+def verify_rsa_sha256(request, rsa_public_key: str):
+    return _verify_rsa('SHA-256', request, rsa_public_key)
+
+
+# ==== RSA-SHA512 ================================================
+
+def sign_rsa_sha512_with_client(sig_base_str: str, client):
+    return _sign_rsa('SHA-512', sig_base_str, client.rsa_key)
+
+
+def verify_rsa_sha512(request, rsa_public_key: str):
+    return _verify_rsa('SHA-512', request, rsa_public_key)
+
+
+# ==== PLAINTEXT =================================================
+
+def sign_plaintext_with_client(_signature_base_string, client):
+    # _signature_base_string is not used because the signature with PLAINTEXT
+    # is just the secret: it isn't a real signature.
+    return sign_plaintext(client.client_secret, client.resource_owner_secret)
 
 
 def sign_plaintext(client_secret, resource_owner_secret):
@@ -516,7 +805,7 @@ def sign_plaintext(client_secret, resource_owner_secret):
     utilize the signature base string or the "oauth_timestamp" and
     "oauth_nonce" parameters.
 
-    .. _`section 3.4.4`: http://tools.ietf.org/html/rfc5849#section-3.4.4
+    .. _`section 3.4.4`: https://tools.ietf.org/html/rfc5849#section-3.4.4
 
     """
 
@@ -525,7 +814,7 @@ def sign_plaintext(client_secret, resource_owner_secret):
 
     # 1.  The client shared-secret, after being encoded (`Section 3.6`_).
     #
-    # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     signature = utils.escape(client_secret or '')
 
     # 2.  An "&" character (ASCII code 38), which MUST be included even
@@ -534,78 +823,21 @@ def sign_plaintext(client_secret, resource_owner_secret):
 
     # 3.  The token shared-secret, after being encoded (`Section 3.6`_).
     #
-    # .. _`Section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    # .. _`Section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
     signature += utils.escape(resource_owner_secret or '')
 
     return signature
 
 
-def sign_plaintext_with_client(base_string, client):
-    return sign_plaintext(client.client_secret, client.resource_owner_secret)
-
-
-def verify_hmac_sha1(request, client_secret=None,
-                     resource_owner_secret=None):
-    """Verify a HMAC-SHA1 signature.
-
-    Per `section 3.4`_ of the spec.
-
-    .. _`section 3.4`: http://tools.ietf.org/html/rfc5849#section-3.4
-
-    To satisfy `RFC2616 section 5.2`_ item 1, the request argument's uri
-    attribute MUST be an absolute URI whose netloc part identifies the
-    origin server or gateway on which the resource resides. Any Host
-    item of the request argument's headers dict attribute will be
-    ignored.
-
-    .. _`RFC2616 section 5.2`: http://tools.ietf.org/html/rfc2616#section-5.2
-
-    """
-    norm_params = normalize_parameters(request.params)
-    uri = normalize_base_string_uri(request.uri)
-    base_string = construct_base_string(request.http_method, uri, norm_params)
-    signature = sign_hmac_sha1(base_string, client_secret,
-                               resource_owner_secret)
-    return safe_string_equals(signature, request.signature)
-
-def _prepare_key_plus(alg, keystr):
-    if isinstance(keystr, bytes_type):
-        keystr = keystr.decode('utf-8')
-    return alg.prepare_key(keystr)
-
-def verify_rsa_sha1(request, rsa_public_key):
-    """Verify a RSASSA-PKCS #1 v1.5 base64 encoded signature.
-
-    Per `section 3.4.3`_ of the spec.
-
-    Note this method requires the jwt and cryptography libraries.
-
-    .. _`section 3.4.3`: http://tools.ietf.org/html/rfc5849#section-3.4.3
-
-    To satisfy `RFC2616 section 5.2`_ item 1, the request argument's uri
-    attribute MUST be an absolute URI whose netloc part identifies the
-    origin server or gateway on which the resource resides. Any Host
-    item of the request argument's headers dict attribute will be
-    ignored.
-
-    .. _`RFC2616 section 5.2`: http://tools.ietf.org/html/rfc2616#section-5.2
-    """
-    norm_params = normalize_parameters(request.params)
-    uri = normalize_base_string_uri(request.uri)
-    message = construct_base_string(request.http_method, uri, norm_params).encode('utf-8')
-    sig = binascii.a2b_base64(request.signature.encode('utf-8'))
-
-    alg = _jwt_rs1_signing_algorithm()
-    key = _prepare_key_plus(alg, rsa_public_key)
-    return alg.verify(message, key, sig)
-
-
 def verify_plaintext(request, client_secret=None, resource_owner_secret=None):
     """Verify a PLAINTEXT signature.
 
     Per `section 3.4`_ of the spec.
 
-    .. _`section 3.4`: http://tools.ietf.org/html/rfc5849#section-3.4
+    .. _`section 3.4`: https://tools.ietf.org/html/rfc5849#section-3.4
     """
     signature = sign_plaintext(client_secret, resource_owner_secret)
-    return safe_string_equals(signature, request.signature)
+    match = safe_string_equals(signature, request.signature)
+    if not match:
+        log.debug('Verify PLAINTEXT failed')
+    return match
diff --git a/lib/oauthlib/oauth1/rfc5849/utils.py b/lib/oauthlib/oauth1/rfc5849/utils.py
index eafb3032..8fb8302e 100644
--- a/lib/oauthlib/oauth1/rfc5849/utils.py
+++ b/lib/oauthlib/oauth1/rfc5849/utils.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.utils
 ~~~~~~~~~~~~~~
@@ -6,14 +5,9 @@ oauthlib.utils
 This module contains utility methods used by various parts of the OAuth
 spec.
 """
-from __future__ import absolute_import, unicode_literals
+import urllib.request as urllib2
 
-try:
-    import urllib2
-except ImportError:
-    import urllib.request as urllib2
-
-from oauthlib.common import quote, unquote, bytes_type, unicode_type
+from oauthlib.common import quote, unquote
 
 UNICODE_ASCII_CHARACTER_SET = ('abcdefghijklmnopqrstuvwxyz'
                                'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
@@ -48,19 +42,19 @@ def escape(u):
 
     Per `section 3.6`_ of the spec.
 
-    .. _`section 3.6`: http://tools.ietf.org/html/rfc5849#section-3.6
+    .. _`section 3.6`: https://tools.ietf.org/html/rfc5849#section-3.6
 
     """
-    if not isinstance(u, unicode_type):
+    if not isinstance(u, str):
         raise ValueError('Only unicode objects are escapable. ' +
-                         'Got %s of type %s.' % (u, type(u)))
+                         'Got {!r} of type {}.'.format(u, type(u)))
     # Letters, digits, and the characters '_.-' are already treated as safe
     # by urllib.quote(). We need to add '~' to fully support rfc5849.
     return quote(u, safe=b'~')
 
 
 def unescape(u):
-    if not isinstance(u, unicode_type):
+    if not isinstance(u, str):
         raise ValueError('Only unicode objects are unescapable.')
     return unquote(u)
 
diff --git a/lib/oauthlib/oauth2/__init__.py b/lib/oauthlib/oauth2/__init__.py
index a13e4848..a6e1cccd 100644
--- a/lib/oauthlib/oauth2/__init__.py
+++ b/lib/oauthlib/oauth2/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2
 ~~~~~~~~~~~~~~
@@ -6,29 +5,31 @@ oauthlib.oauth2
 This module is a wrapper for the most recent implementation of OAuth 2.0 Client
 and Server classes.
 """
-from __future__ import absolute_import, unicode_literals
-
-from .rfc6749.clients import Client
-from .rfc6749.clients import WebApplicationClient
-from .rfc6749.clients import MobileApplicationClient
-from .rfc6749.clients import LegacyApplicationClient
-from .rfc6749.clients import BackendApplicationClient
-from .rfc6749.clients import ServiceApplicationClient
-from .rfc6749.endpoints import AuthorizationEndpoint
-from .rfc6749.endpoints import TokenEndpoint
-from .rfc6749.endpoints import ResourceEndpoint
-from .rfc6749.endpoints import RevocationEndpoint
-from .rfc6749.endpoints import Server
-from .rfc6749.endpoints import WebApplicationServer
-from .rfc6749.endpoints import MobileApplicationServer
-from .rfc6749.endpoints import LegacyApplicationServer
-from .rfc6749.endpoints import BackendApplicationServer
-from .rfc6749.errors import *
-from .rfc6749.grant_types import AuthorizationCodeGrant
-from .rfc6749.grant_types import ImplicitGrant
-from .rfc6749.grant_types import ResourceOwnerPasswordCredentialsGrant
-from .rfc6749.grant_types import ClientCredentialsGrant
-from .rfc6749.grant_types import RefreshTokenGrant
+from .rfc6749.clients import (
+    BackendApplicationClient, Client, LegacyApplicationClient,
+    MobileApplicationClient, ServiceApplicationClient, WebApplicationClient,
+)
+from .rfc6749.endpoints import (
+    AuthorizationEndpoint, BackendApplicationServer, IntrospectEndpoint,
+    LegacyApplicationServer, MetadataEndpoint, MobileApplicationServer,
+    ResourceEndpoint, RevocationEndpoint, Server, TokenEndpoint,
+    WebApplicationServer,
+)
+from .rfc6749.errors import (
+    AccessDeniedError, FatalClientError, InsecureTransportError,
+    InvalidClientError, InvalidClientIdError, InvalidGrantError,
+    InvalidRedirectURIError, InvalidRequestError, InvalidRequestFatalError,
+    InvalidScopeError, MismatchingRedirectURIError, MismatchingStateError,
+    MissingClientIdError, MissingCodeError, MissingRedirectURIError,
+    MissingResponseTypeError, MissingTokenError, MissingTokenTypeError,
+    OAuth2Error, ServerError, TemporarilyUnavailableError, TokenExpiredError,
+    UnauthorizedClientError, UnsupportedGrantTypeError,
+    UnsupportedResponseTypeError, UnsupportedTokenTypeError,
+)
+from .rfc6749.grant_types import (
+    AuthorizationCodeGrant, ClientCredentialsGrant, ImplicitGrant,
+    RefreshTokenGrant, ResourceOwnerPasswordCredentialsGrant,
+)
 from .rfc6749.request_validator import RequestValidator
 from .rfc6749.tokens import BearerToken, OAuth2Token
 from .rfc6749.utils import is_secure_transport
diff --git a/lib/oauthlib/oauth2/rfc6749/__init__.py b/lib/oauthlib/oauth2/rfc6749/__init__.py
index aff0ed88..4b75a8a1 100644
--- a/lib/oauthlib/oauth2/rfc6749/__init__.py
+++ b/lib/oauthlib/oauth2/rfc6749/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,61 +5,12 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import functools
 import logging
 
-from .errors import TemporarilyUnavailableError, ServerError
-from .errors import FatalClientError, OAuth2Error
-
+from .endpoints.base import BaseEndpoint, catch_errors_and_unavailability
+from .errors import (
+    FatalClientError, OAuth2Error, ServerError, TemporarilyUnavailableError,
+)
 
 log = logging.getLogger(__name__)
-
-
-class BaseEndpoint(object):
-
-    def __init__(self):
-        self._available = True
-        self._catch_errors = False
-
-    @property
-    def available(self):
-        return self._available
-
-    @available.setter
-    def available(self, available):
-        self._available = available
-
-    @property
-    def catch_errors(self):
-        return self._catch_errors
-
-    @catch_errors.setter
-    def catch_errors(self, catch_errors):
-        self._catch_errors = catch_errors
-
-
-def catch_errors_and_unavailability(f):
-    @functools.wraps(f)
-    def wrapper(endpoint, uri, *args, **kwargs):
-        if not endpoint.available:
-            e = TemporarilyUnavailableError()
-            log.info('Endpoint unavailable, ignoring request %s.' % uri)
-            return {}, e.json, 503
-
-        if endpoint.catch_errors:
-            try:
-                return f(endpoint, uri, *args, **kwargs)
-            except OAuth2Error:
-                raise
-            except FatalClientError:
-                raise
-            except Exception as e:
-                error = ServerError()
-                log.warning(
-                    'Exception caught while processing request, %s.' % e)
-                return {}, error.json, 500
-        else:
-            return f(endpoint, uri, *args, **kwargs)
-    return wrapper
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/__init__.py b/lib/oauthlib/oauth2/rfc6749/clients/__init__.py
index 65bea501..8fc6c955 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/__init__.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/__init__.py
@@ -6,11 +6,9 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
-from .base import *
-from .web_application import WebApplicationClient
-from .mobile_application import MobileApplicationClient
-from .legacy_application import LegacyApplicationClient
 from .backend_application import BackendApplicationClient
+from .base import AUTH_HEADER, BODY, URI_QUERY, Client
+from .legacy_application import LegacyApplicationClient
+from .mobile_application import MobileApplicationClient
 from .service_application import ServiceApplicationClient
+from .web_application import WebApplicationClient
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/backend_application.py b/lib/oauthlib/oauth2/rfc6749/clients/backend_application.py
index 445bdd5b..0e2a8299 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/backend_application.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/backend_application.py
@@ -6,11 +6,8 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
-from .base import Client
 from ..parameters import prepare_token_request
-from ..parameters import parse_token_response
+from .base import Client
 
 
 class BackendApplicationClient(Client):
@@ -31,15 +28,28 @@ class BackendApplicationClient(Client):
     no additional authorization request is needed.
     """
 
-    def prepare_request_body(self, body='', scope=None, **kwargs):
+    grant_type = 'client_credentials'
+
+    def prepare_request_body(self, body='', scope=None,
+                             include_client_id=False, **kwargs):
         """Add the client credentials to the request body.
 
         The client makes a request to the token endpoint by adding the
         following parameters using the "application/x-www-form-urlencoded"
         format per `Appendix B`_ in the HTTP request entity-body:
 
+        :param body: Existing request body (URL encoded string) to embed parameters
+                     into. This may contain extra paramters. Default ''.
         :param scope:   The scope of the access request as described by
                         `Section 3.3`_.
+
+        :param include_client_id: `True` to send the `client_id` in the
+                                  body of the upstream request. This is required
+                                  if the client is not authenticating with the
+                                  authorization server as described in
+                                  `Section 3.2.1`_. False otherwise (default).
+        :type include_client_id: Boolean
+
         :param kwargs:  Extra credentials to include in the token request.
 
         The client MUST authenticate with the authorization server as
@@ -53,9 +63,12 @@ class BackendApplicationClient(Client):
             >>> client.prepare_request_body(scope=['hello', 'world'])
             'grant_type=client_credentials&scope=hello+world'
 
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 3.2.1`: http://tools.ietf.org/html/rfc6749#section-3.2.1
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 3.2.1`: https://tools.ietf.org/html/rfc6749#section-3.2.1
         """
-        return prepare_token_request('client_credentials', body=body,
+        kwargs['client_id'] = self.client_id
+        kwargs['include_client_id'] = include_client_id
+        scope = self.scope if scope is None else scope
+        return prepare_token_request(self.grant_type, body=body,
                                      scope=scope, **kwargs)
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/base.py b/lib/oauthlib/oauth2/rfc6749/clients/base.py
index 4af9e767..88065ab3 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/base.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/base.py
@@ -6,20 +6,20 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import time
+import warnings
 
 from oauthlib.common import generate_token
 from oauthlib.oauth2.rfc6749 import tokens
-from oauthlib.oauth2.rfc6749.parameters import parse_token_response
-from oauthlib.oauth2.rfc6749.parameters import prepare_token_request
-from oauthlib.oauth2.rfc6749.parameters import prepare_token_revocation_request
-from oauthlib.oauth2.rfc6749.errors import TokenExpiredError
-from oauthlib.oauth2.rfc6749.errors import InsecureTransportError
+from oauthlib.oauth2.rfc6749.errors import (
+    InsecureTransportError, TokenExpiredError,
+)
+from oauthlib.oauth2.rfc6749.parameters import (
+    parse_token_response, prepare_token_request,
+    prepare_token_revocation_request,
+)
 from oauthlib.oauth2.rfc6749.utils import is_secure_transport
 
-
 AUTH_HEADER = 'auth_header'
 URI_QUERY = 'query'
 BODY = 'body'
@@ -28,8 +28,8 @@ FORM_ENC_HEADERS = {
     'Content-Type': 'application/x-www-form-urlencoded'
 }
 
-class Client(object):
 
+class Client:
     """Base OAuth2 client responsible for access token management.
 
     This class also acts as a generic interface providing methods common to all
@@ -47,6 +47,7 @@ class Client(object):
     Python, this is usually :py:class:`oauthlib.oauth2.WebApplicationClient`.
 
     """
+    refresh_token_key = 'refresh_token'
 
     def __init__(self, client_id,
                  default_token_placement=AUTH_HEADER,
@@ -80,7 +81,7 @@ class Client(object):
         ``token`` dict parameter.
 
         :param refresh_token: A refresh token (string) used to refresh expired
-        tokens. Can also be supplide inside the ``token`` dict parameter.
+        tokens. Can also be supplied inside the ``token`` dict parameter.
 
         :param mac_key: Encryption key used with MAC tokens.
 
@@ -112,8 +113,10 @@ class Client(object):
         self.state_generator = state_generator
         self.state = state
         self.redirect_url = redirect_url
+        self.code = None
+        self.expires_in = None
         self._expires_at = None
-        self._populate_attributes(self.token)
+        self.populate_token_attributes(self.token)
 
     @property
     def token_types(self):
@@ -141,6 +144,7 @@ class Client(object):
 
     def parse_request_uri_response(self, *args, **kwargs):
         """Abstract method used to parse redirection responses."""
+        raise NotImplementedError("Must be implemented by inheriting classes.")
 
     def add_token(self, uri, http_method='GET', body=None, headers=None,
                   token_placement=None, **kwargs):
@@ -174,20 +178,20 @@ class Client(object):
                                 nonce="274312:dj83hs9s",
                                 mac="kDZvddkndxvhGRXZhvuDjEWhGeE="
 
-        .. _`I-D.ietf-oauth-v2-bearer`: http://tools.ietf.org/html/rfc6749#section-12.2
-        .. _`I-D.ietf-oauth-v2-http-mac`: http://tools.ietf.org/html/rfc6749#section-12.2
+        .. _`I-D.ietf-oauth-v2-bearer`: https://tools.ietf.org/html/rfc6749#section-12.2
+        .. _`I-D.ietf-oauth-v2-http-mac`: https://tools.ietf.org/html/rfc6749#section-12.2
         """
         if not is_secure_transport(uri):
             raise InsecureTransportError()
 
         token_placement = token_placement or self.default_token_placement
 
-        case_insensitive_token_types = dict(
-            (k.lower(), v) for k, v in self.token_types.items())
+        case_insensitive_token_types = {
+            k.lower(): v for k, v in self.token_types.items()}
         if not self.token_type.lower() in case_insensitive_token_types:
             raise ValueError("Unsupported token type: %s" % self.token_type)
 
-        if not self.access_token:
+        if not (self.access_token or self.token.get('access_token')):
             raise ValueError("Missing access token.")
 
         if self._expires_at and self._expires_at < time.time():
@@ -197,7 +201,7 @@ class Client(object):
                                                                      headers, token_placement, **kwargs)
 
     def prepare_authorization_request(self, authorization_url, state=None,
-            redirect_url=None, scope=None, **kwargs):
+                                      redirect_url=None, scope=None, **kwargs):
         """Prepare the authorization request.
 
         This is the first step in many OAuth flows in which the user is
@@ -218,6 +222,11 @@ class Client(object):
         the provider. If provided then it must also be provided in the
         token request.
 
+        :param scope: List of scopes to request. Must be equal to
+        or a subset of the scopes granted when obtaining the refresh
+        token. If none is provided, the ones provided in the constructor are
+        used.
+
         :param kwargs: Additional parameters to included in the request.
 
         :returns: The prepared request tuple with (url, headers, body).
@@ -227,14 +236,15 @@ class Client(object):
 
         self.state = state or self.state_generator()
         self.redirect_url = redirect_url or self.redirect_url
-        self.scope = scope or self.scope
+        # do not assign scope to self automatically anymore
+        scope = self.scope if scope is None else scope
         auth_url = self.prepare_request_uri(
-                authorization_url, redirect_uri=self.redirect_url,
-                scope=self.scope, state=self.state, **kwargs)
+            authorization_url, redirect_uri=self.redirect_url,
+            scope=scope, state=self.state, **kwargs)
         return auth_url, FORM_ENC_HEADERS, ''
 
     def prepare_token_request(self, token_url, authorization_response=None,
-            redirect_url=None, state=None, body='', **kwargs):
+                              redirect_url=None, state=None, body='', **kwargs):
         """Prepare a token creation request.
 
         Note that these requests usually require client authentication, either
@@ -251,7 +261,10 @@ class Client(object):
         :param redirect_url: The redirect_url supplied with the authorization
         request (if there was one).
 
-        :param body: Request body (URL encoded string).
+        :param state:
+
+        :param body: Existing request body (URL encoded string) to embed parameters
+                     into. This may contain extra paramters. Default ''.
 
         :param kwargs: Additional parameters to included in the request.
 
@@ -263,15 +276,15 @@ class Client(object):
         state = state or self.state
         if authorization_response:
             self.parse_request_uri_response(
-                    authorization_response, state=state)
+                authorization_response, state=state)
         self.redirect_url = redirect_url or self.redirect_url
         body = self.prepare_request_body(body=body,
-                redirect_uri=self.redirect_url, **kwargs)
+                                         redirect_uri=self.redirect_url, **kwargs)
 
         return token_url, FORM_ENC_HEADERS, body
 
     def prepare_refresh_token_request(self, token_url, refresh_token=None,
-            body='', scope=None, **kwargs):
+                                      body='', scope=None, **kwargs):
         """Prepare an access token refresh request.
 
         Expired access tokens can be replaced by new access tokens without
@@ -283,11 +296,13 @@ class Client(object):
 
         :param refresh_token: Refresh token string.
 
-        :param body: Request body (URL encoded string).
+        :param body: Existing request body (URL encoded string) to embed parameters
+                     into. This may contain extra paramters. Default ''.
 
         :param scope: List of scopes to request. Must be equal to
         or a subset of the scopes granted when obtaining the refresh
-        token.
+        token. If none is provided, the ones provided in the constructor are
+        used.
 
         :param kwargs: Additional parameters to included in the request.
 
@@ -296,13 +311,14 @@ class Client(object):
         if not is_secure_transport(token_url):
             raise InsecureTransportError()
 
-        self.scope = scope or self.scope
+        # do not assign scope to self automatically anymore
+        scope = self.scope if scope is None else scope
         body = self.prepare_refresh_body(body=body,
-                refresh_token=refresh_token, scope=self.scope, **kwargs)
+                                         refresh_token=refresh_token, scope=scope, **kwargs)
         return token_url, FORM_ENC_HEADERS, body
 
     def prepare_token_revocation_request(self, revocation_url, token,
-            token_type_hint="access_token", body='', callback=None, **kwargs):
+                                         token_type_hint="access_token", body='', callback=None, **kwargs):
         """Prepare a token revocation request.
 
         :param revocation_url: Provider token revocation endpoint URL.
@@ -313,6 +329,8 @@ class Client(object):
         ``"refresh_token"``. This is optional and if you wish to not pass it you
         must provide ``token_type_hint=None``.
 
+        :param body:
+
         :param callback: A jsonp callback such as ``package.callback`` to be invoked
         upon receiving the response. Not that it should not include a () suffix.
 
@@ -357,8 +375,8 @@ class Client(object):
             raise InsecureTransportError()
 
         return prepare_token_revocation_request(revocation_url, token,
-                token_type_hint=token_type_hint, body=body, callback=callback,
-                **kwargs)
+                                                token_type_hint=token_type_hint, body=body, callback=callback,
+                                                **kwargs)
 
     def parse_request_body_response(self, body, scope=None, **kwargs):
         """Parse the JSON response body.
@@ -370,7 +388,8 @@ class Client(object):
         returns an error response as described in `Section 5.2`_.
 
         :param body: The response body from the token request.
-        :param scope: Scopes originally requested.
+        :param scope: Scopes originally requested. If none is provided, the ones
+        provided in the constructor are used.
         :return: Dictionary of token parameters.
         :raises: Warning if scope has changed. OAuth2Error if response is invalid.
 
@@ -398,16 +417,17 @@ class Client(object):
             If omitted, the authorization server SHOULD provide the
             expiration time via other means or document the default value.
 
-        **scope**
+           **scope**
             Providers may supply this in all responses but are required to only
             if it has changed since the authorization request.
 
-        .. _`Section 5.1`: http://tools.ietf.org/html/rfc6749#section-5.1
-        .. _`Section 5.2`: http://tools.ietf.org/html/rfc6749#section-5.2
-        .. _`Section 7.1`: http://tools.ietf.org/html/rfc6749#section-7.1
+        .. _`Section 5.1`: https://tools.ietf.org/html/rfc6749#section-5.1
+        .. _`Section 5.2`: https://tools.ietf.org/html/rfc6749#section-5.2
+        .. _`Section 7.1`: https://tools.ietf.org/html/rfc6749#section-7.1
         """
+        scope = self.scope if scope is None else scope
         self.token = parse_token_response(body, scope=scope)
-        self._populate_attributes(self.token)
+        self.populate_token_attributes(self.token)
         return self.token
 
     def prepare_refresh_body(self, body='', refresh_token=None, scope=None, **kwargs):
@@ -427,10 +447,12 @@ class Client(object):
                 Section 3.3.  The requested scope MUST NOT include any scope
                 not originally granted by the resource owner, and if omitted is
                 treated as equal to the scope originally granted by the
-                resource owner.
+                resource owner. Note that if none is provided, the ones provided
+                in the constructor are used if any.
         """
         refresh_token = refresh_token or self.refresh_token
-        return prepare_token_request('refresh_token', body=body, scope=scope,
+        scope = self.scope if scope is None else scope
+        return prepare_token_request(self.refresh_token_key, body=body, scope=scope,
                                      refresh_token=refresh_token, **kwargs)
 
     def _add_bearer_token(self, uri, http_method='GET', body=None,
@@ -455,13 +477,27 @@ class Client(object):
 
         Warning: MAC token support is experimental as the spec is not yet stable.
         """
+        if token_placement != AUTH_HEADER:
+            raise ValueError("Invalid token placement.")
+
         headers = tokens.prepare_mac_header(self.access_token, uri,
                                             self.mac_key, http_method, headers=headers, body=body, ext=ext,
                                             hash_algorithm=self.mac_algorithm, **kwargs)
         return uri, headers, body
 
     def _populate_attributes(self, response):
-        """Add commonly used values such as access_token to self."""
+        warnings.warn("Please switch to the public method "
+                      "populate_token_attributes.", DeprecationWarning)
+        return self.populate_token_attributes(response)
+
+    def populate_code_attributes(self, response):
+        """Add attributes from an auth code response to self."""
+
+        if 'code' in response:
+            self.code = response.get('code')
+
+    def populate_token_attributes(self, response):
+        """Add attributes from a token exchange response to self."""
 
         if 'access_token' in response:
             self.access_token = response.get('access_token')
@@ -479,12 +515,8 @@ class Client(object):
         if 'expires_at' in response:
             self._expires_at = int(response.get('expires_at'))
 
-        if 'code' in response:
-            self.code = response.get('code')
-
         if 'mac_key' in response:
             self.mac_key = response.get('mac_key')
 
         if 'mac_algorithm' in response:
             self.mac_algorithm = response.get('mac_algorithm')
-
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/legacy_application.py b/lib/oauthlib/oauth2/rfc6749/clients/legacy_application.py
index e4e522ac..7af68f34 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/legacy_application.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/legacy_application.py
@@ -6,11 +6,8 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
-from .base import Client
 from ..parameters import prepare_token_request
-from ..parameters import parse_token_response
+from .base import Client
 
 
 class LegacyApplicationClient(Client):
@@ -36,10 +33,13 @@ class LegacyApplicationClient(Client):
     MUST discard the credentials once an access token has been obtained.
     """
 
-    def __init__(self, client_id, **kwargs):
-        super(LegacyApplicationClient, self).__init__(client_id, **kwargs)
+    grant_type = 'password'
 
-    def prepare_request_body(self, username, password, body='', scope=None, **kwargs):
+    def __init__(self, client_id, **kwargs):
+        super().__init__(client_id, **kwargs)
+
+    def prepare_request_body(self, username, password, body='', scope=None,
+                             include_client_id=False, **kwargs):
         """Add the resource owner password and username to the request body.
 
         The client makes a request to the token endpoint by adding the
@@ -48,8 +48,16 @@ class LegacyApplicationClient(Client):
 
         :param username:    The resource owner username.
         :param password:    The resource owner password.
+        :param body: Existing request body (URL encoded string) to embed parameters
+                     into. This may contain extra paramters. Default ''.
         :param scope:   The scope of the access request as described by
                         `Section 3.3`_.
+        :param include_client_id: `True` to send the `client_id` in the
+                                  body of the upstream request. This is required
+                                  if the client is not authenticating with the
+                                  authorization server as described in
+                                  `Section 3.2.1`_. False otherwise (default).
+        :type include_client_id: Boolean
         :param kwargs:  Extra credentials to include in the token request.
 
         If the client type is confidential or the client was issued client
@@ -65,9 +73,12 @@ class LegacyApplicationClient(Client):
             >>> client.prepare_request_body(username='foo', password='bar', scope=['hello', 'world'])
             'grant_type=password&username=foo&scope=hello+world&password=bar'
 
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 3.2.1`: http://tools.ietf.org/html/rfc6749#section-3.2.1
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 3.2.1`: https://tools.ietf.org/html/rfc6749#section-3.2.1
         """
-        return prepare_token_request('password', body=body, username=username,
+        kwargs['client_id'] = self.client_id
+        kwargs['include_client_id'] = include_client_id
+        scope = self.scope if scope is None else scope
+        return prepare_token_request(self.grant_type, body=body, username=username,
                                      password=password, scope=scope, **kwargs)
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/mobile_application.py b/lib/oauthlib/oauth2/rfc6749/clients/mobile_application.py
index 9e3ef216..cd325f4e 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/mobile_application.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/mobile_application.py
@@ -6,11 +6,8 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
+from ..parameters import parse_implicit_response, prepare_grant_uri
 from .base import Client
-from ..parameters import prepare_grant_uri
-from ..parameters import parse_implicit_response
 
 
 class MobileApplicationClient(Client):
@@ -46,6 +43,8 @@ class MobileApplicationClient(Client):
     redirection URI, it may be exposed to the resource owner and other
     applications residing on the same device.
     """
+    
+    response_type = 'token'
 
     def prepare_request_uri(self, uri, redirect_uri=None, scope=None,
                             state=None, **kwargs):
@@ -86,13 +85,14 @@ class MobileApplicationClient(Client):
             >>> client.prepare_request_uri('https://example.com', foo='bar')
             'https://example.com?client_id=your_id&response_type=token&foo=bar'
 
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
-        .. _`Section 2.2`: http://tools.ietf.org/html/rfc6749#section-2.2
-        .. _`Section 3.1.2`: http://tools.ietf.org/html/rfc6749#section-3.1.2
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 10.12`: http://tools.ietf.org/html/rfc6749#section-10.12
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 2.2`: https://tools.ietf.org/html/rfc6749#section-2.2
+        .. _`Section 3.1.2`: https://tools.ietf.org/html/rfc6749#section-3.1.2
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 10.12`: https://tools.ietf.org/html/rfc6749#section-10.12
         """
-        return prepare_grant_uri(uri, self.client_id, 'token',
+        scope = self.scope if scope is None else scope
+        return prepare_grant_uri(uri, self.client_id, self.response_type,
                                  redirect_uri=redirect_uri, state=state, scope=scope, **kwargs)
 
     def parse_request_uri_response(self, uri, state=None, scope=None):
@@ -165,9 +165,10 @@ class MobileApplicationClient(Client):
             >>> client.parse_request_body_response(response_body, scope=['other'])
             ('Scope has changed from "other" to "hello world".', ['other'], ['hello', 'world'])
 
-        .. _`Section 7.1`: http://tools.ietf.org/html/rfc6749#section-7.1
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 7.1`: https://tools.ietf.org/html/rfc6749#section-7.1
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
         """
+        scope = self.scope if scope is None else scope
         self.token = parse_implicit_response(uri, state=state, scope=scope)
-        self._populate_attributes(self.token)
+        self.populate_token_attributes(self.token)
         return self.token
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/service_application.py b/lib/oauthlib/oauth2/rfc6749/clients/service_application.py
index 36da98b4..c751c8b0 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/service_application.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/service_application.py
@@ -6,15 +6,12 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import time
 
 from oauthlib.common import to_unicode
 
-from .base import Client
 from ..parameters import prepare_token_request
-from ..parameters import parse_token_response
+from .base import Client
 
 
 class ServiceApplicationClient(Client):
@@ -42,38 +39,39 @@ class ServiceApplicationClient(Client):
         :param private_key: Private key used for signing and encrypting.
                             Must be given as a string.
 
-        :param subject: The principal that is the subject of the JWT, i.e. 
+        :param subject: The principal that is the subject of the JWT, i.e.
                         which user is the token requested on behalf of.
                         For example, ``foo@example.com.
 
         :param issuer: The JWT MUST contain an "iss" (issuer) claim that
                        contains a unique identifier for the entity that issued
-                       the JWT. For example, ``your-client@provider.com``. 
+                       the JWT. For example, ``your-client@provider.com``.
 
         :param audience: A value identifying the authorization server as an
                          intended audience, e.g.
                          ``https://provider.com/oauth2/token``.
 
         :param kwargs: Additional arguments to pass to base client, such as
-                       state and token. See Client.__init__.__doc__ for 
+                       state and token. See ``Client.__init__.__doc__`` for
                        details.
         """
-        super(ServiceApplicationClient, self).__init__(client_id, **kwargs)
+        super().__init__(client_id, **kwargs)
         self.private_key = private_key
         self.subject = subject
         self.issuer = issuer
         self.audience = audience
 
-    def prepare_request_body(self, 
+    def prepare_request_body(self,
                              private_key=None,
-                             subject=None, 
-                             issuer=None, 
-                             audience=None, 
-                             expires_at=None, 
+                             subject=None,
+                             issuer=None,
+                             audience=None,
+                             expires_at=None,
                              issued_at=None,
                              extra_claims=None,
-                             body='', 
-                             scope=None, 
+                             body='',
+                             scope=None,
+                             include_client_id=False,
                              **kwargs):
         """Create and add a JWT assertion to the request body.
 
@@ -86,7 +84,7 @@ class ServiceApplicationClient(Client):
 
         :param issuer: (iss) The JWT MUST contain an "iss" (issuer) claim that
                        contains a unique identifier for the entity that issued
-                       the JWT. For example, ``your-client@provider.com``. 
+                       the JWT. For example, ``your-client@provider.com``.
 
         :param audience: (aud) A value identifying the authorization server as an
                          intended audience, e.g.
@@ -98,26 +96,38 @@ class ServiceApplicationClient(Client):
         :param issued_at: A unix timestamp of when the JWT was created.
                           Defaults to now, i.e. ``time.time()``.
 
-        :param not_before: A unix timestamp after which the JWT may be used.
-                           Not included unless provided.
-
-        :param jwt_id: A unique JWT token identifier. Not included unless
-                       provided.
-
         :param extra_claims: A dict of additional claims to include in the JWT.
 
+        :param body: Existing request body (URL encoded string) to embed parameters
+                     into. This may contain extra paramters. Default ''.
+
         :param scope: The scope of the access request.
 
-        :param body: Request body (string) with extra parameters.
+        :param include_client_id: `True` to send the `client_id` in the
+                                  body of the upstream request. This is required
+                                  if the client is not authenticating with the
+                                  authorization server as described in
+                                  `Section 3.2.1`_. False otherwise (default).
+        :type include_client_id: Boolean
+
+        :param not_before: A unix timestamp after which the JWT may be used.
+                           Not included unless provided. *
+
+        :param jwt_id: A unique JWT token identifier. Not included unless
+                       provided. *
 
         :param kwargs: Extra credentials to include in the token request.
 
+        Parameters marked with a `*` above are not explicit arguments in the
+        function signature, but are specially documented arguments for items
+        appearing in the generic `**kwargs` keyworded input.
+
         The "scope" parameter may be used, as defined in the Assertion
         Framework for OAuth 2.0 Client Authentication and Authorization Grants
         [I-D.ietf-oauth-assertions] specification, to indicate the requested
         scope.
 
-        Authentication of the client is optional, as described in 
+        Authentication of the client is optional, as described in
         `Section 3.2.1`_ of OAuth 2.0 [RFC6749] and consequently, the
         "client_id" is only needed when a form of client authentication that
         relies on the parameter is used.
@@ -137,7 +147,7 @@ class ServiceApplicationClient(Client):
             eyJpc3Mi[...omitted for brevity...].
             J9l-ZhwP[...omitted for brevity...]
 
-        .. _`Section 3.2.1`: http://tools.ietf.org/html/rfc6749#section-3.2.1
+        .. _`Section 3.2.1`: https://tools.ietf.org/html/rfc6749#section-3.2.1
         """
         import jwt
 
@@ -147,8 +157,8 @@ class ServiceApplicationClient(Client):
                              ' token requests.')
         claim = {
             'iss': issuer or self.issuer,
-            'aud': audience or self.issuer,
-            'sub': subject or self.issuer,
+            'aud': audience or self.audience,
+            'sub': subject or self.subject,
             'exp': int(expires_at or time.time() + 3600),
             'iat': int(issued_at or time.time()),
         }
@@ -169,8 +179,11 @@ class ServiceApplicationClient(Client):
         assertion = jwt.encode(claim, key, 'RS256')
         assertion = to_unicode(assertion)
 
+        kwargs['client_id'] = self.client_id
+        kwargs['include_client_id'] = include_client_id
+        scope = self.scope if scope is None else scope
         return prepare_token_request(self.grant_type,
                                      body=body,
                                      assertion=assertion,
-                                     scope=scope, 
+                                     scope=scope,
                                      **kwargs)
diff --git a/lib/oauthlib/oauth2/rfc6749/clients/web_application.py b/lib/oauthlib/oauth2/rfc6749/clients/web_application.py
index c685d3c2..a1f3db1d 100644
--- a/lib/oauthlib/oauth2/rfc6749/clients/web_application.py
+++ b/lib/oauthlib/oauth2/rfc6749/clients/web_application.py
@@ -6,12 +6,13 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
+import warnings
 
+from ..parameters import (
+    parse_authorization_code_response, prepare_grant_uri,
+    prepare_token_request,
+)
 from .base import Client
-from ..parameters import prepare_grant_uri, prepare_token_request
-from ..parameters import parse_authorization_code_response
-from ..parameters import parse_token_response
 
 
 class WebApplicationClient(Client):
@@ -32,9 +33,11 @@ class WebApplicationClient(Client):
     browser) and capable of receiving incoming requests (via redirection)
     from the authorization server.
     """
+    
+    grant_type = 'authorization_code'
 
     def __init__(self, client_id, code=None, **kwargs):
-        super(WebApplicationClient, self).__init__(client_id, **kwargs)
+        super().__init__(client_id, **kwargs)
         self.code = code
 
     def prepare_request_uri(self, uri, redirect_uri=None, scope=None,
@@ -76,26 +79,24 @@ class WebApplicationClient(Client):
             >>> client.prepare_request_uri('https://example.com', foo='bar')
             'https://example.com?client_id=your_id&response_type=code&foo=bar'
 
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
-        .. _`Section 2.2`: http://tools.ietf.org/html/rfc6749#section-2.2
-        .. _`Section 3.1.2`: http://tools.ietf.org/html/rfc6749#section-3.1.2
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 10.12`: http://tools.ietf.org/html/rfc6749#section-10.12
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 2.2`: https://tools.ietf.org/html/rfc6749#section-2.2
+        .. _`Section 3.1.2`: https://tools.ietf.org/html/rfc6749#section-3.1.2
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 10.12`: https://tools.ietf.org/html/rfc6749#section-10.12
         """
+        scope = self.scope if scope is None else scope
         return prepare_grant_uri(uri, self.client_id, 'code',
                                  redirect_uri=redirect_uri, scope=scope, state=state, **kwargs)
 
-    def prepare_request_body(self, client_id=None, code=None, body='',
-                             redirect_uri=None, **kwargs):
+    def prepare_request_body(self, code=None, redirect_uri=None, body='',
+                             include_client_id=True, **kwargs):
         """Prepare the access token request body.
 
         The client makes a request to the token endpoint by adding the
         following parameters using the "application/x-www-form-urlencoded"
         format in the HTTP request entity-body:
 
-        :param client_id:   REQUIRED, if the client is not authenticating with the
-                            authorization server as described in `Section 3.2.1`_.
-
         :param code:    REQUIRED. The authorization code received from the
                         authorization server.
 
@@ -103,6 +104,15 @@ class WebApplicationClient(Client):
                                 authorization request as described in `Section 4.1.1`_, and their
                                 values MUST be identical.
 
+        :param body: Existing request body (URL encoded string) to embed parameters
+                     into. This may contain extra paramters. Default ''.
+
+        :param include_client_id: `True` (default) to send the `client_id` in the
+                                  body of the upstream request. This is required
+                                  if the client is not authenticating with the
+                                  authorization server as described in `Section 3.2.1`_.
+        :type include_client_id: Boolean
+
         :param kwargs: Extra parameters to include in the token request.
 
         In addition OAuthLib will add the ``grant_type`` parameter set to
@@ -120,12 +130,31 @@ class WebApplicationClient(Client):
             >>> client.prepare_request_body(code='sh35ksdf09sf', foo='bar')
             'grant_type=authorization_code&code=sh35ksdf09sf&foo=bar'
 
-        .. _`Section 4.1.1`: http://tools.ietf.org/html/rfc6749#section-4.1.1
-        .. _`Section 3.2.1`: http://tools.ietf.org/html/rfc6749#section-3.2.1
+        `Section 3.2.1` also states:
+            In the "authorization_code" "grant_type" request to the token
+            endpoint, an unauthenticated client MUST send its "client_id" to
+            prevent itself from inadvertently accepting a code intended for a
+            client with a different "client_id".  This protects the client from
+            substitution of the authentication code.  (It provides no additional
+            security for the protected resource.)
+
+        .. _`Section 4.1.1`: https://tools.ietf.org/html/rfc6749#section-4.1.1
+        .. _`Section 3.2.1`: https://tools.ietf.org/html/rfc6749#section-3.2.1
         """
         code = code or self.code
-        return prepare_token_request('authorization_code', code=code, body=body,
-                                     client_id=self.client_id, redirect_uri=redirect_uri, **kwargs)
+        if 'client_id' in kwargs:
+            warnings.warn("`client_id` has been deprecated in favor of "
+                          "`include_client_id`, a boolean value which will "
+                          "include the already configured `self.client_id`.",
+                          DeprecationWarning)
+            if kwargs['client_id'] != self.client_id:
+                raise ValueError("`client_id` was supplied as an argument, but "
+                                 "it does not match `self.client_id`")
+
+        kwargs['client_id'] = self.client_id
+        kwargs['include_client_id'] = include_client_id
+        return prepare_token_request(self.grant_type, code=code, body=body,
+                                     redirect_uri=redirect_uri, **kwargs)
 
     def parse_request_uri_response(self, uri, state=None):
         """Parse the URI query for code and state.
@@ -172,5 +201,5 @@ class WebApplicationClient(Client):
             oauthlib.oauth2.rfc6749.errors.MismatchingStateError
         """
         response = parse_authorization_code_response(uri, state=state)
-        self._populate_attributes(response)
+        self.populate_code_attributes(response)
         return response
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/__init__.py b/lib/oauthlib/oauth2/rfc6749/endpoints/__init__.py
index 848bec6b..1695b41b 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/__init__.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/__init__.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,14 +5,13 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 from .authorization import AuthorizationEndpoint
-from .token import TokenEndpoint
+from .introspect import IntrospectEndpoint
+from .metadata import MetadataEndpoint
+from .pre_configured import (
+    BackendApplicationServer, LegacyApplicationServer, MobileApplicationServer,
+    Server, WebApplicationServer,
+)
 from .resource import ResourceEndpoint
 from .revocation import RevocationEndpoint
-from .pre_configured import Server
-from .pre_configured import WebApplicationServer
-from .pre_configured import MobileApplicationServer
-from .pre_configured import LegacyApplicationServer
-from .pre_configured import BackendApplicationServer
+from .token import TokenEndpoint
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/authorization.py b/lib/oauthlib/oauth2/rfc6749/endpoints/authorization.py
index ada24d70..71967865 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/authorization.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/authorization.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,11 +5,10 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
 from oauthlib.common import Request
+from oauthlib.oauth2.rfc6749 import utils
 
 from .base import BaseEndpoint, catch_errors_and_unavailability
 
@@ -58,7 +56,7 @@ class AuthorizationEndpoint(BaseEndpoint):
 
         # Enforced through the design of oauthlib.common.Request
 
-    .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
+    .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
     """
 
     def __init__(self, default_response_type, default_token_type,
@@ -108,7 +106,9 @@ class AuthorizationEndpoint(BaseEndpoint):
         """Extract response_type and route to the designated handler."""
         request = Request(
             uri, http_method=http_method, body=body, headers=headers)
-        request.scopes = None
+
+        request.scopes = utils.scope_to_list(request.scope)
+
         response_type_handler = self.response_types.get(
             request.response_type, self.default_response_type_handler)
         return response_type_handler.validate_authorization_request(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/base.py b/lib/oauthlib/oauth2/rfc6749/endpoints/base.py
index 759c6c8c..3f239917 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/base.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/base.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,22 +5,34 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import functools
 import logging
 
-from ..errors import TemporarilyUnavailableError, ServerError
-from ..errors import FatalClientError, OAuth2Error
+from ..errors import (
+    FatalClientError, InvalidClientError, InvalidRequestError, OAuth2Error,
+    ServerError, TemporarilyUnavailableError, UnsupportedTokenTypeError,
+)
 
 log = logging.getLogger(__name__)
 
 
-class BaseEndpoint(object):
+class BaseEndpoint:
 
     def __init__(self):
         self._available = True
         self._catch_errors = False
+        self._valid_request_methods = None
+
+    @property
+    def valid_request_methods(self):
+        return self._valid_request_methods
+
+    @valid_request_methods.setter
+    def valid_request_methods(self, valid_request_methods):
+        if valid_request_methods is not None:
+            valid_request_methods = [x.upper() for x in valid_request_methods]
+        self._valid_request_methods = valid_request_methods
+    
 
     @property
     def available(self):
@@ -29,7 +40,7 @@ class BaseEndpoint(object):
 
     @available.setter
     def available(self, available):
-        self._available = available
+        self._available = available       
 
     @property
     def catch_errors(self):
@@ -39,6 +50,43 @@ class BaseEndpoint(object):
     def catch_errors(self, catch_errors):
         self._catch_errors = catch_errors
 
+    def _raise_on_missing_token(self, request):
+        """Raise error on missing token."""
+        if not request.token:
+            raise InvalidRequestError(request=request,
+                                      description='Missing token parameter.')
+    def _raise_on_invalid_client(self, request):
+        """Raise on failed client authentication."""
+        if self.request_validator.client_authentication_required(request):
+            if not self.request_validator.authenticate_client(request):
+                log.debug('Client authentication failed, %r.', request)
+                raise InvalidClientError(request=request)
+        elif not self.request_validator.authenticate_client_id(request.client_id, request):
+            log.debug('Client authentication failed, %r.', request)
+            raise InvalidClientError(request=request)
+
+    def _raise_on_unsupported_token(self, request):
+        """Raise on unsupported tokens."""
+        if (request.token_type_hint and
+            request.token_type_hint in self.valid_token_types and
+            request.token_type_hint not in self.supported_token_types):
+            raise UnsupportedTokenTypeError(request=request)
+
+    def _raise_on_bad_method(self, request):
+        if self.valid_request_methods is None:
+            raise ValueError('Configure "valid_request_methods" property first')
+        if request.http_method.upper() not in self.valid_request_methods:
+            raise InvalidRequestError(request=request,
+                                      description=('Unsupported request method %s' % request.http_method.upper()))
+
+    def _raise_on_bad_post_request(self, request):
+        """Raise if invalid POST request received
+        """
+        if request.http_method.upper() == 'POST':
+            query_params = request.uri_query or ""
+            if query_params:
+                raise InvalidRequestError(request=request,
+                                          description=('URL query parameters are not allowed'))
 
 def catch_errors_and_unavailability(f):
     @functools.wraps(f)
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/introspect.py b/lib/oauthlib/oauth2/rfc6749/endpoints/introspect.py
new file mode 100644
index 00000000..63570d9c
--- /dev/null
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/introspect.py
@@ -0,0 +1,122 @@
+"""
+oauthlib.oauth2.rfc6749.endpoint.introspect
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An implementation of the OAuth 2.0 `Token Introspection`.
+
+.. _`Token Introspection`: https://tools.ietf.org/html/rfc7662
+"""
+import json
+import logging
+
+from oauthlib.common import Request
+
+from ..errors import OAuth2Error
+from .base import BaseEndpoint, catch_errors_and_unavailability
+
+log = logging.getLogger(__name__)
+
+
+class IntrospectEndpoint(BaseEndpoint):
+
+    """Introspect token endpoint.
+
+   This endpoint defines a method to query an OAuth 2.0 authorization
+   server to determine the active state of an OAuth 2.0 token and to
+   determine meta-information about this token. OAuth 2.0 deployments
+   can use this method to convey information about the authorization
+   context of the token from the authorization server to the protected
+   resource.
+
+   To prevent the values of access tokens from leaking into
+   server-side logs via query parameters, an authorization server
+   offering token introspection MAY disallow the use of HTTP GET on
+   the introspection endpoint and instead require the HTTP POST method
+   to be used at the introspection endpoint.
+   """
+
+    valid_token_types = ('access_token', 'refresh_token')
+    valid_request_methods = ('POST',)
+
+    def __init__(self, request_validator, supported_token_types=None):
+        BaseEndpoint.__init__(self)
+        self.request_validator = request_validator
+        self.supported_token_types = (
+            supported_token_types or self.valid_token_types)
+
+    @catch_errors_and_unavailability
+    def create_introspect_response(self, uri, http_method='POST', body=None,
+                                   headers=None):
+        """Create introspect valid or invalid response
+
+        If the authorization server is unable to determine the state
+        of the token without additional information, it SHOULD return
+        an introspection response indicating the token is not active
+        as described in Section 2.2.
+        """
+        resp_headers = {
+            'Content-Type': 'application/json',
+            'Cache-Control': 'no-store',
+            'Pragma': 'no-cache',
+        }
+        request = Request(uri, http_method, body, headers)
+        try:
+            self.validate_introspect_request(request)
+            log.debug('Token introspect valid for %r.', request)
+        except OAuth2Error as e:
+            log.debug('Client error during validation of %r. %r.', request, e)
+            resp_headers.update(e.headers)
+            return resp_headers, e.json, e.status_code
+
+        claims = self.request_validator.introspect_token(
+            request.token,
+            request.token_type_hint,
+            request
+        )
+        if claims is None:
+            return resp_headers, json.dumps(dict(active=False)), 200
+        if "active" in claims:
+            claims.pop("active")
+        return resp_headers, json.dumps(dict(active=True, **claims)), 200
+
+    def validate_introspect_request(self, request):
+        """Ensure the request is valid.
+
+        The protected resource calls the introspection endpoint using
+        an HTTP POST request with parameters sent as
+        "application/x-www-form-urlencoded".
+
+        token REQUIRED.  The string value of the token.
+
+        token_type_hint OPTIONAL.
+        A hint about the type of the token submitted for
+        introspection.  The protected resource MAY pass this parameter to
+        help the authorization server optimize the token lookup.  If the
+        server is unable to locate the token using the given hint, it MUST
+        extend its search across all of its supported token types.  An
+        authorization server MAY ignore this parameter, particularly if it
+        is able to detect the token type automatically.
+            *  access_token: An Access Token as defined in [`RFC6749`],
+                `section 1.4`_
+
+            *  refresh_token: A Refresh Token as defined in [`RFC6749`],
+                `section 1.5`_
+
+        The introspection endpoint MAY accept other OPTIONAL
+        parameters to provide further context to the query.  For
+        instance, an authorization server may desire to know the IP
+        address of the client accessing the protected resource to
+        determine if the correct client is likely to be presenting the
+        token.  The definition of this or any other parameters are
+        outside the scope of this specification, to be defined by
+        service documentation or extensions to this specification.
+
+        .. _`section 1.4`: http://tools.ietf.org/html/rfc6749#section-1.4
+        .. _`section 1.5`: http://tools.ietf.org/html/rfc6749#section-1.5
+        .. _`RFC6749`: http://tools.ietf.org/html/rfc6749
+        """
+        self._raise_on_bad_method(request)
+        self._raise_on_bad_post_request(request)
+        self._raise_on_missing_token(request)
+        self._raise_on_invalid_client(request)
+        self._raise_on_unsupported_token(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/metadata.py b/lib/oauthlib/oauth2/rfc6749/endpoints/metadata.py
new file mode 100644
index 00000000..81ee1def
--- /dev/null
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/metadata.py
@@ -0,0 +1,237 @@
+"""
+oauthlib.oauth2.rfc6749.endpoint.metadata
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An implementation of the `OAuth 2.0 Authorization Server Metadata`.
+
+.. _`OAuth 2.0 Authorization Server Metadata`: https://tools.ietf.org/html/rfc8414
+"""
+import copy
+import json
+import logging
+
+from .. import grant_types
+from .authorization import AuthorizationEndpoint
+from .base import BaseEndpoint, catch_errors_and_unavailability
+from .introspect import IntrospectEndpoint
+from .revocation import RevocationEndpoint
+from .token import TokenEndpoint
+
+log = logging.getLogger(__name__)
+
+
+class MetadataEndpoint(BaseEndpoint):
+
+    """OAuth2.0 Authorization Server Metadata endpoint.
+
+   This specification generalizes the metadata format defined by
+   `OpenID Connect Discovery 1.0` in a way that is compatible
+   with OpenID Connect Discovery while being applicable to a wider set
+   of OAuth 2.0 use cases.  This is intentionally parallel to the way
+   that OAuth 2.0 Dynamic Client Registration Protocol [`RFC7591`_]
+   generalized the dynamic client registration mechanisms defined by
+   OpenID Connect Dynamic Client Registration 1.0
+   in a way that is compatible with it.
+
+   .. _`OpenID Connect Discovery 1.0`: https://openid.net/specs/openid-connect-discovery-1_0.html
+   .. _`RFC7591`: https://tools.ietf.org/html/rfc7591
+   """
+
+    def __init__(self, endpoints, claims={}, raise_errors=True):
+        assert isinstance(claims, dict)
+        for endpoint in endpoints:
+            assert isinstance(endpoint, BaseEndpoint)
+
+        BaseEndpoint.__init__(self)
+        self.raise_errors = raise_errors
+        self.endpoints = endpoints
+        self.initial_claims = claims
+        self.claims = self.validate_metadata_server()
+
+    @catch_errors_and_unavailability
+    def create_metadata_response(self, uri, http_method='GET', body=None,
+                                 headers=None):
+        """Create metadata response
+        """
+        headers = {
+            'Content-Type': 'application/json'
+        }
+        return headers, json.dumps(self.claims), 200
+
+    def validate_metadata(self, array, key, is_required=False, is_list=False, is_url=False, is_issuer=False):
+        if not self.raise_errors:
+            return
+
+        if key not in array:
+            if is_required:
+                raise ValueError("key {} is a mandatory metadata.".format(key))
+
+        elif is_issuer:
+            if not array[key].startswith("https"):
+                raise ValueError("key {}: {} must be an HTTPS URL".format(key, array[key]))
+            if "?" in array[key] or "&" in array[key] or "#" in array[key]:
+                raise ValueError("key {}: {} must not contain query or fragment components".format(key, array[key]))
+
+        elif is_url:
+            if not array[key].startswith("http"):
+                raise ValueError("key {}: {} must be an URL".format(key, array[key]))
+
+        elif is_list:
+            if not isinstance(array[key], list):
+                raise ValueError("key {}: {} must be an Array".format(key, array[key]))
+            for elem in array[key]:
+                if not isinstance(elem, str):
+                    raise ValueError("array {}: {} must contains only string (not {})".format(key, array[key], elem))
+
+    def validate_metadata_token(self, claims, endpoint):
+        """
+        If the token endpoint is used in the grant type, the value of this
+        parameter MUST be the same as the value of the "grant_type"
+        parameter passed to the token endpoint defined in the grant type
+        definition.
+        """
+        self._grant_types.extend(endpoint._grant_types.keys())
+        claims.setdefault("token_endpoint_auth_methods_supported", ["client_secret_post", "client_secret_basic"])
+
+        self.validate_metadata(claims, "token_endpoint_auth_methods_supported", is_list=True)
+        self.validate_metadata(claims, "token_endpoint_auth_signing_alg_values_supported", is_list=True)
+        self.validate_metadata(claims, "token_endpoint", is_required=True, is_url=True)
+
+    def validate_metadata_authorization(self, claims, endpoint):
+        claims.setdefault("response_types_supported",
+                          list(filter(lambda x: x != "none", endpoint._response_types.keys())))
+        claims.setdefault("response_modes_supported", ["query", "fragment"])
+
+        # The OAuth2.0 Implicit flow is defined as a "grant type" but it is not
+        # using the "token" endpoint, as such, we have to add it explicitly to
+        # the list of "grant_types_supported" when enabled.
+        if "token" in claims["response_types_supported"]:
+            self._grant_types.append("implicit")
+
+        self.validate_metadata(claims, "response_types_supported", is_required=True, is_list=True)
+        self.validate_metadata(claims, "response_modes_supported", is_list=True)
+        if "code" in claims["response_types_supported"]:
+            code_grant = endpoint._response_types["code"]
+            if not isinstance(code_grant, grant_types.AuthorizationCodeGrant) and hasattr(code_grant, "default_grant"):
+                code_grant = code_grant.default_grant
+
+            claims.setdefault("code_challenge_methods_supported",
+                              list(code_grant._code_challenge_methods.keys()))
+            self.validate_metadata(claims, "code_challenge_methods_supported", is_list=True)
+        self.validate_metadata(claims, "authorization_endpoint", is_required=True, is_url=True)
+
+    def validate_metadata_revocation(self, claims, endpoint):
+        claims.setdefault("revocation_endpoint_auth_methods_supported",
+                          ["client_secret_post", "client_secret_basic"])
+
+        self.validate_metadata(claims, "revocation_endpoint_auth_methods_supported", is_list=True)
+        self.validate_metadata(claims, "revocation_endpoint_auth_signing_alg_values_supported", is_list=True)
+        self.validate_metadata(claims, "revocation_endpoint", is_required=True, is_url=True)
+
+    def validate_metadata_introspection(self, claims, endpoint):
+        claims.setdefault("introspection_endpoint_auth_methods_supported",
+                          ["client_secret_post", "client_secret_basic"])
+
+        self.validate_metadata(claims, "introspection_endpoint_auth_methods_supported", is_list=True)
+        self.validate_metadata(claims, "introspection_endpoint_auth_signing_alg_values_supported", is_list=True)
+        self.validate_metadata(claims, "introspection_endpoint", is_required=True, is_url=True)
+
+    def validate_metadata_server(self):
+        """
+        Authorization servers can have metadata describing their
+        configuration.  The following authorization server metadata values
+        are used by this specification. More details can be found in
+        `RFC8414 section 2`_ :
+
+       issuer
+          REQUIRED
+
+       authorization_endpoint
+          URL of the authorization server's authorization endpoint
+          [`RFC6749#Authorization`_].  This is REQUIRED unless no grant types are supported
+          that use the authorization endpoint.
+
+       token_endpoint
+          URL of the authorization server's token endpoint [`RFC6749#Token`_].  This
+          is REQUIRED unless only the implicit grant type is supported.
+
+       scopes_supported
+          RECOMMENDED.
+
+       response_types_supported
+          REQUIRED.
+
+       Other OPTIONAL fields:
+          jwks_uri,
+          registration_endpoint,
+          response_modes_supported
+
+       grant_types_supported
+          OPTIONAL.  JSON array containing a list of the OAuth 2.0 grant
+          type values that this authorization server supports.  The array
+          values used are the same as those used with the "grant_types"
+          parameter defined by "OAuth 2.0 Dynamic Client Registration
+          Protocol" [`RFC7591`_].  If omitted, the default value is
+          "["authorization_code", "implicit"]".
+
+       token_endpoint_auth_methods_supported
+
+       token_endpoint_auth_signing_alg_values_supported
+
+       service_documentation
+
+       ui_locales_supported
+
+       op_policy_uri
+
+       op_tos_uri
+
+       revocation_endpoint
+
+       revocation_endpoint_auth_methods_supported
+
+       revocation_endpoint_auth_signing_alg_values_supported
+
+       introspection_endpoint
+
+       introspection_endpoint_auth_methods_supported
+
+       introspection_endpoint_auth_signing_alg_values_supported
+
+       code_challenge_methods_supported
+
+       Additional authorization server metadata parameters MAY also be used.
+       Some are defined by other specifications, such as OpenID Connect
+       Discovery 1.0 [`OpenID.Discovery`_].
+
+        .. _`RFC8414 section 2`: https://tools.ietf.org/html/rfc8414#section-2
+        .. _`RFC6749#Authorization`: https://tools.ietf.org/html/rfc6749#section-3.1
+        .. _`RFC6749#Token`: https://tools.ietf.org/html/rfc6749#section-3.2
+        .. _`RFC7591`: https://tools.ietf.org/html/rfc7591
+        .. _`OpenID.Discovery`: https://openid.net/specs/openid-connect-discovery-1_0.html
+        """
+        claims = copy.deepcopy(self.initial_claims)
+        self.validate_metadata(claims, "issuer", is_required=True, is_issuer=True)
+        self.validate_metadata(claims, "jwks_uri", is_url=True)
+        self.validate_metadata(claims, "scopes_supported", is_list=True)
+        self.validate_metadata(claims, "service_documentation", is_url=True)
+        self.validate_metadata(claims, "ui_locales_supported", is_list=True)
+        self.validate_metadata(claims, "op_policy_uri", is_url=True)
+        self.validate_metadata(claims, "op_tos_uri", is_url=True)
+
+        self._grant_types = []
+        for endpoint in self.endpoints:
+            if isinstance(endpoint, TokenEndpoint):
+                self.validate_metadata_token(claims, endpoint)
+            if isinstance(endpoint, AuthorizationEndpoint):
+                self.validate_metadata_authorization(claims, endpoint)
+            if isinstance(endpoint, RevocationEndpoint):
+                self.validate_metadata_revocation(claims, endpoint)
+            if isinstance(endpoint, IntrospectEndpoint):
+                self.validate_metadata_introspection(claims, endpoint)
+
+        # "grant_types_supported" is a combination of all OAuth2 grant types
+        # allowed in the current provider implementation.
+        claims.setdefault("grant_types_supported", self._grant_types)
+        self.validate_metadata(claims, "grant_types_supported", is_list=True)
+        return claims
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/pre_configured.py b/lib/oauthlib/oauth2/rfc6749/endpoints/pre_configured.py
index 21ed2dd2..d64a1663 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/pre_configured.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/pre_configured.py
@@ -1,28 +1,24 @@
-# -*- coding: utf-8 -*-
 """
-oauthlib.oauth2.rfc6749
-~~~~~~~~~~~~~~~~~~~~~~~
+oauthlib.oauth2.rfc6749.endpoints.pre_configured
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-This module is an implementation of various logic needed
-for consuming and providing OAuth 2.0 RFC6749.
+This module is an implementation of various endpoints needed
+for providing OAuth 2.0 RFC6749 servers.
 """
-from __future__ import absolute_import, unicode_literals
-
+from ..grant_types import (
+    AuthorizationCodeGrant, ClientCredentialsGrant, ImplicitGrant,
+    RefreshTokenGrant, ResourceOwnerPasswordCredentialsGrant,
+)
 from ..tokens import BearerToken
-from ..grant_types import AuthorizationCodeGrant
-from ..grant_types import ImplicitGrant
-from ..grant_types import ResourceOwnerPasswordCredentialsGrant
-from ..grant_types import ClientCredentialsGrant
-from ..grant_types import RefreshTokenGrant
-
 from .authorization import AuthorizationEndpoint
-from .token import TokenEndpoint
+from .introspect import IntrospectEndpoint
 from .resource import ResourceEndpoint
 from .revocation import RevocationEndpoint
+from .token import TokenEndpoint
 
 
-class Server(AuthorizationEndpoint, TokenEndpoint, ResourceEndpoint,
-             RevocationEndpoint):
+class Server(AuthorizationEndpoint, IntrospectEndpoint, TokenEndpoint,
+             ResourceEndpoint, RevocationEndpoint):
 
     """An all-in-one endpoint featuring all four major grant types."""
 
@@ -42,35 +38,40 @@ class Server(AuthorizationEndpoint, TokenEndpoint, ResourceEndpoint,
         :param kwargs: Extra parameters to pass to authorization-,
                        token-, resource-, and revocation-endpoint constructors.
         """
-        auth_grant = AuthorizationCodeGrant(request_validator)
-        implicit_grant = ImplicitGrant(request_validator)
-        password_grant = ResourceOwnerPasswordCredentialsGrant(
+        self.auth_grant = AuthorizationCodeGrant(request_validator)
+        self.implicit_grant = ImplicitGrant(request_validator)
+        self.password_grant = ResourceOwnerPasswordCredentialsGrant(
             request_validator)
-        credentials_grant = ClientCredentialsGrant(request_validator)
-        refresh_grant = RefreshTokenGrant(request_validator)
-        bearer = BearerToken(request_validator, token_generator,
+        self.credentials_grant = ClientCredentialsGrant(request_validator)
+        self.refresh_grant = RefreshTokenGrant(request_validator)
+
+        self.bearer = BearerToken(request_validator, token_generator,
                              token_expires_in, refresh_token_generator)
+
         AuthorizationEndpoint.__init__(self, default_response_type='code',
                                        response_types={
-                                           'code': auth_grant,
-                                           'token': implicit_grant,
+                                           'code': self.auth_grant,
+                                           'token': self.implicit_grant,
+                                           'none': self.auth_grant
                                        },
-                                       default_token_type=bearer)
+                                       default_token_type=self.bearer)
+
         TokenEndpoint.__init__(self, default_grant_type='authorization_code',
                                grant_types={
-                                   'authorization_code': auth_grant,
-                                   'password': password_grant,
-                                   'client_credentials': credentials_grant,
-                                   'refresh_token': refresh_grant,
+                                   'authorization_code': self.auth_grant,
+                                   'password': self.password_grant,
+                                   'client_credentials': self.credentials_grant,
+                                   'refresh_token': self.refresh_grant,
                                },
-                               default_token_type=bearer)
+                               default_token_type=self.bearer)
         ResourceEndpoint.__init__(self, default_token='Bearer',
-                                  token_types={'Bearer': bearer})
+                                  token_types={'Bearer': self.bearer})
         RevocationEndpoint.__init__(self, request_validator)
+        IntrospectEndpoint.__init__(self, request_validator)
 
 
-class WebApplicationServer(AuthorizationEndpoint, TokenEndpoint, ResourceEndpoint,
-                           RevocationEndpoint):
+class WebApplicationServer(AuthorizationEndpoint, IntrospectEndpoint, TokenEndpoint,
+                           ResourceEndpoint, RevocationEndpoint):
 
     """An all-in-one endpoint featuring Authorization code grant and Bearer tokens."""
 
@@ -89,26 +90,27 @@ class WebApplicationServer(AuthorizationEndpoint, TokenEndpoint, ResourceEndpoin
         :param kwargs: Extra parameters to pass to authorization-,
                        token-, resource-, and revocation-endpoint constructors.
         """
-        auth_grant = AuthorizationCodeGrant(request_validator)
-        refresh_grant = RefreshTokenGrant(request_validator)
-        bearer = BearerToken(request_validator, token_generator,
+        self.auth_grant = AuthorizationCodeGrant(request_validator)
+        self.refresh_grant = RefreshTokenGrant(request_validator)
+        self.bearer = BearerToken(request_validator, token_generator,
                              token_expires_in, refresh_token_generator)
         AuthorizationEndpoint.__init__(self, default_response_type='code',
-                                       response_types={'code': auth_grant},
-                                       default_token_type=bearer)
+                                       response_types={'code': self.auth_grant},
+                                       default_token_type=self.bearer)
         TokenEndpoint.__init__(self, default_grant_type='authorization_code',
                                grant_types={
-                                   'authorization_code': auth_grant,
-                                   'refresh_token': refresh_grant,
+                                   'authorization_code': self.auth_grant,
+                                   'refresh_token': self.refresh_grant,
                                },
-                               default_token_type=bearer)
+                               default_token_type=self.bearer)
         ResourceEndpoint.__init__(self, default_token='Bearer',
-                                  token_types={'Bearer': bearer})
+                                  token_types={'Bearer': self.bearer})
         RevocationEndpoint.__init__(self, request_validator)
+        IntrospectEndpoint.__init__(self, request_validator)
 
 
-class MobileApplicationServer(AuthorizationEndpoint, ResourceEndpoint,
-                              RevocationEndpoint):
+class MobileApplicationServer(AuthorizationEndpoint, IntrospectEndpoint,
+                              ResourceEndpoint, RevocationEndpoint):
 
     """An all-in-one endpoint featuring Implicit code grant and Bearer tokens."""
 
@@ -127,21 +129,23 @@ class MobileApplicationServer(AuthorizationEndpoint, ResourceEndpoint,
         :param kwargs: Extra parameters to pass to authorization-,
                        token-, resource-, and revocation-endpoint constructors.
         """
-        implicit_grant = ImplicitGrant(request_validator)
-        bearer = BearerToken(request_validator, token_generator,
+        self.implicit_grant = ImplicitGrant(request_validator)
+        self.bearer = BearerToken(request_validator, token_generator,
                              token_expires_in, refresh_token_generator)
         AuthorizationEndpoint.__init__(self, default_response_type='token',
                                        response_types={
-                                           'token': implicit_grant},
-                                       default_token_type=bearer)
+                                           'token': self.implicit_grant},
+                                       default_token_type=self.bearer)
         ResourceEndpoint.__init__(self, default_token='Bearer',
-                                  token_types={'Bearer': bearer})
+                                  token_types={'Bearer': self.bearer})
         RevocationEndpoint.__init__(self, request_validator,
                                     supported_token_types=['access_token'])
+        IntrospectEndpoint.__init__(self, request_validator,
+                                    supported_token_types=['access_token'])
 
 
-class LegacyApplicationServer(TokenEndpoint, ResourceEndpoint,
-                              RevocationEndpoint):
+class LegacyApplicationServer(TokenEndpoint, IntrospectEndpoint,
+                              ResourceEndpoint, RevocationEndpoint):
 
     """An all-in-one endpoint featuring Resource Owner Password Credentials grant and Bearer tokens."""
 
@@ -160,24 +164,25 @@ class LegacyApplicationServer(TokenEndpoint, ResourceEndpoint,
         :param kwargs: Extra parameters to pass to authorization-,
                        token-, resource-, and revocation-endpoint constructors.
         """
-        password_grant = ResourceOwnerPasswordCredentialsGrant(
+        self.password_grant = ResourceOwnerPasswordCredentialsGrant(
             request_validator)
-        refresh_grant = RefreshTokenGrant(request_validator)
-        bearer = BearerToken(request_validator, token_generator,
+        self.refresh_grant = RefreshTokenGrant(request_validator)
+        self.bearer = BearerToken(request_validator, token_generator,
                              token_expires_in, refresh_token_generator)
         TokenEndpoint.__init__(self, default_grant_type='password',
                                grant_types={
-                                   'password': password_grant,
-                                   'refresh_token': refresh_grant,
+                                   'password': self.password_grant,
+                                   'refresh_token': self.refresh_grant,
                                },
-                               default_token_type=bearer)
+                               default_token_type=self.bearer)
         ResourceEndpoint.__init__(self, default_token='Bearer',
-                                  token_types={'Bearer': bearer})
+                                  token_types={'Bearer': self.bearer})
         RevocationEndpoint.__init__(self, request_validator)
+        IntrospectEndpoint.__init__(self, request_validator)
 
 
-class BackendApplicationServer(TokenEndpoint, ResourceEndpoint,
-                               RevocationEndpoint):
+class BackendApplicationServer(TokenEndpoint, IntrospectEndpoint,
+                               ResourceEndpoint, RevocationEndpoint):
 
     """An all-in-one endpoint featuring Client Credentials grant and Bearer tokens."""
 
@@ -196,14 +201,16 @@ class BackendApplicationServer(TokenEndpoint, ResourceEndpoint,
         :param kwargs: Extra parameters to pass to authorization-,
                        token-, resource-, and revocation-endpoint constructors.
         """
-        credentials_grant = ClientCredentialsGrant(request_validator)
-        bearer = BearerToken(request_validator, token_generator,
+        self.credentials_grant = ClientCredentialsGrant(request_validator)
+        self.bearer = BearerToken(request_validator, token_generator,
                              token_expires_in, refresh_token_generator)
         TokenEndpoint.__init__(self, default_grant_type='client_credentials',
                                grant_types={
-                                   'client_credentials': credentials_grant},
-                               default_token_type=bearer)
+                                   'client_credentials': self.credentials_grant},
+                               default_token_type=self.bearer)
         ResourceEndpoint.__init__(self, default_token='Bearer',
-                                  token_types={'Bearer': bearer})
+                                  token_types={'Bearer': self.bearer})
         RevocationEndpoint.__init__(self, request_validator,
                                     supported_token_types=['access_token'])
+        IntrospectEndpoint.__init__(self, request_validator,
+                                    supported_token_types=['access_token'])
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/resource.py b/lib/oauthlib/oauth2/rfc6749/endpoints/resource.py
index d03ed214..f7562255 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/resource.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/resource.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,8 +5,6 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
 from oauthlib.common import Request
@@ -83,5 +80,5 @@ class ResourceEndpoint(BaseEndpoint):
         to give an estimation based on the request.
         """
         estimates = sorted(((t.estimate_type(request), n)
-                            for n, t in self.tokens.items()))
+                            for n, t in self.tokens.items()), reverse=True)
         return estimates[0][1] if len(estimates) else None
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/revocation.py b/lib/oauthlib/oauth2/rfc6749/endpoints/revocation.py
index 662c7933..4aa5ec6e 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/revocation.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/revocation.py
@@ -1,21 +1,17 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.endpoint.revocation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 An implementation of the OAuth 2 `Token Revocation`_ spec (draft 11).
 
-.. _`Token Revocation`: http://tools.ietf.org/html/draft-ietf-oauth-revocation-11
+.. _`Token Revocation`: https://tools.ietf.org/html/draft-ietf-oauth-revocation-11
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
 from oauthlib.common import Request
 
+from ..errors import OAuth2Error
 from .base import BaseEndpoint, catch_errors_and_unavailability
-from ..errors import InvalidClientError, UnsupportedTokenTypeError
-from ..errors import InvalidRequestError, OAuth2Error
 
 log = logging.getLogger(__name__)
 
@@ -29,6 +25,7 @@ class RevocationEndpoint(BaseEndpoint):
     """
 
     valid_token_types = ('access_token', 'refresh_token')
+    valid_request_methods = ('POST',)
 
     def __init__(self, request_validator, supported_token_types=None,
             enable_jsonp=False):
@@ -59,6 +56,11 @@ class RevocationEndpoint(BaseEndpoint):
         An invalid token type hint value is ignored by the authorization server
         and does not influence the revocation response.
         """
+        resp_headers = {
+            'Content-Type': 'application/json',
+            'Cache-Control': 'no-store',
+            'Pragma': 'no-cache',
+        }
         request = Request(
             uri, http_method=http_method, body=body, headers=headers)
         try:
@@ -68,8 +70,9 @@ class RevocationEndpoint(BaseEndpoint):
             log.debug('Client error during validation of %r. %r.', request, e)
             response_body = e.json
             if self.enable_jsonp and request.callback:
-                response_body = '%s(%s);' % (request.callback, response_body)
-            return {}, response_body, e.status_code
+                response_body = '{}({});'.format(request.callback, response_body)
+            resp_headers.update(e.headers)
+            return resp_headers, response_body, e.status_code
 
         self.request_validator.revoke_token(request.token,
                                             request.token_type_hint, request)
@@ -110,21 +113,14 @@ class RevocationEndpoint(BaseEndpoint):
         The client also includes its authentication credentials as described in
         `Section 2.3`_. of [`RFC6749`_].
 
-        .. _`section 1.4`: http://tools.ietf.org/html/rfc6749#section-1.4
-        .. _`section 1.5`: http://tools.ietf.org/html/rfc6749#section-1.5
-        .. _`section 2.3`: http://tools.ietf.org/html/rfc6749#section-2.3
-        .. _`Section 4.1.2`: http://tools.ietf.org/html/draft-ietf-oauth-revocation-11#section-4.1.2
-        .. _`RFC6749`: http://tools.ietf.org/html/rfc6749
+        .. _`section 1.4`: https://tools.ietf.org/html/rfc6749#section-1.4
+        .. _`section 1.5`: https://tools.ietf.org/html/rfc6749#section-1.5
+        .. _`section 2.3`: https://tools.ietf.org/html/rfc6749#section-2.3
+        .. _`Section 4.1.2`: https://tools.ietf.org/html/draft-ietf-oauth-revocation-11#section-4.1.2
+        .. _`RFC6749`: https://tools.ietf.org/html/rfc6749
         """
-        if not request.token:
-            raise InvalidRequestError(request=request,
-                                      description='Missing token parameter.')
-
-        if self.request_validator.client_authentication_required(request):
-            if not self.request_validator.authenticate_client(request):
-                raise InvalidClientError(request=request)
-
-        if (request.token_type_hint and
-                request.token_type_hint in self.valid_token_types and
-                request.token_type_hint not in self.supported_token_types):
-            raise UnsupportedTokenTypeError(request=request)
+        self._raise_on_bad_method(request)
+        self._raise_on_bad_post_request(request)
+        self._raise_on_missing_token(request)
+        self._raise_on_invalid_client(request)
+        self._raise_on_unsupported_token(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/endpoints/token.py b/lib/oauthlib/oauth2/rfc6749/endpoints/token.py
index cda56ad0..ab9e0918 100644
--- a/lib/oauthlib/oauth2/rfc6749/endpoints/token.py
+++ b/lib/oauthlib/oauth2/rfc6749/endpoints/token.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749
 ~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,15 +5,13 @@ oauthlib.oauth2.rfc6749
 This module is an implementation of various logic needed
 for consuming and providing OAuth 2.0 RFC6749.
 """
-from __future__ import absolute_import, unicode_literals
-
 import logging
 
 from oauthlib.common import Request
+from oauthlib.oauth2.rfc6749 import utils
 
 from .base import BaseEndpoint, catch_errors_and_unavailability
 
-
 log = logging.getLogger(__name__)
 
 
@@ -39,7 +36,6 @@ class TokenEndpoint(BaseEndpoint):
         https://example.com/path?query=component             # OK
         https://example.com/path?query=component#fragment    # Not OK
 
-    Since requests to the authorization endpoint result in user
     Since requests to the token endpoint result in the transmission of
     clear-text credentials (in the HTTP request and response), the
     authorization server MUST require the use of TLS as described in
@@ -59,9 +55,11 @@ class TokenEndpoint(BaseEndpoint):
 
         # Delegated to each grant type.
 
-    .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
+    .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
     """
 
+    valid_request_methods = ('POST',)
+
     def __init__(self, default_grant_type, default_token_type, grant_types):
         BaseEndpoint.__init__(self)
         self._grant_types = grant_types
@@ -85,16 +83,37 @@ class TokenEndpoint(BaseEndpoint):
         return self._default_token_type
 
     @catch_errors_and_unavailability
-    def create_token_response(self, uri, http_method='GET', body=None,
-                              headers=None, credentials=None):
+    def create_token_response(self, uri, http_method='POST', body=None,
+                              headers=None, credentials=None, grant_type_for_scope=None,
+                              claims=None):
         """Extract grant_type and route to the designated handler."""
         request = Request(
             uri, http_method=http_method, body=body, headers=headers)
-        request.scopes = None
+        self.validate_token_request(request)
+        # 'scope' is an allowed Token Request param in both the "Resource Owner Password Credentials Grant"
+        # and "Client Credentials Grant" flows
+        # https://tools.ietf.org/html/rfc6749#section-4.3.2
+        # https://tools.ietf.org/html/rfc6749#section-4.4.2
+        request.scopes = utils.scope_to_list(request.scope)
+
         request.extra_credentials = credentials
+        if grant_type_for_scope:
+            request.grant_type = grant_type_for_scope
+
+        # OpenID Connect claims, if provided.  The server using oauthlib might choose
+        # to implement the claims parameter of the Authorization Request.  In this case
+        # it should retrieve those claims and pass them via the claims argument here,
+        # as a dict.
+        if claims:
+            request.claims = claims
+
         grant_type_handler = self.grant_types.get(request.grant_type,
                                                   self.default_grant_type_handler)
         log.debug('Dispatching grant_type %s request to %r.',
                   request.grant_type, grant_type_handler)
         return grant_type_handler.create_token_response(
             request, self.default_token_type)
+
+    def validate_token_request(self, request):
+        self._raise_on_bad_method(request)
+        self._raise_on_bad_post_request(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/errors.py b/lib/oauthlib/oauth2/rfc6749/errors.py
index 88f5375a..b01e247b 100644
--- a/lib/oauthlib/oauth2/rfc6749/errors.py
+++ b/lib/oauthlib/oauth2/rfc6749/errors.py
@@ -1,4 +1,3 @@
-# coding=utf-8
 """
 oauthlib.oauth2.rfc6749.errors
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -6,9 +5,9 @@ oauthlib.oauth2.rfc6749.errors
 Error used both by OAuth 2 clients and providers to represent the spec
 defined error responses for all four core grant types.
 """
-from __future__ import unicode_literals
 import json
-from oauthlib.common import urlencode, add_params_to_uri
+
+from oauthlib.common import add_params_to_uri, urlencode
 
 
 class OAuth2Error(Exception):
@@ -16,32 +15,37 @@ class OAuth2Error(Exception):
     status_code = 400
     description = ''
 
-    def __init__(self, description=None, uri=None, state=None, status_code=None,
-                 request=None):
+    def __init__(self, description=None, uri=None, state=None,
+                 status_code=None, request=None):
         """
-        description:    A human-readable ASCII [USASCII] text providing
-                        additional information, used to assist the client
-                        developer in understanding the error that occurred.
-                        Values for the "error_description" parameter MUST NOT
-                        include characters outside the set
-                        x20-21 / x23-5B / x5D-7E.
+        :param description: A human-readable ASCII [USASCII] text providing
+                            additional information, used to assist the client
+                            developer in understanding the error that occurred.
+                            Values for the "error_description" parameter
+                            MUST NOT include characters outside the set
+                            x20-21 / x23-5B / x5D-7E.
 
-        uri:    A URI identifying a human-readable web page with information
-                about the error, used to provide the client developer with
-                additional information about the error.  Values for the
-                "error_uri" parameter MUST conform to the URI- Reference
-                syntax, and thus MUST NOT include characters outside the set
-                x21 / x23-5B / x5D-7E.
+        :param uri: A URI identifying a human-readable web page with information
+                    about the error, used to provide the client developer with
+                    additional information about the error.  Values for the
+                    "error_uri" parameter MUST conform to the URI- Reference
+                    syntax, and thus MUST NOT include characters outside the set
+                    x21 / x23-5B / x5D-7E.
 
-        state:  A CSRF protection value received from the client.
+        :param state: A CSRF protection value received from the client.
 
-        request:  Oauthlib Request object
+        :param status_code:
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         """
-        self.description = description or self.description
-        message = '(%s) %s' % (self.error, self.description)
+        if description is not None:
+            self.description = description
+
+        message = '({}) {}'.format(self.error, self.description)
         if request:
             message += ' ' + repr(request)
-        super(OAuth2Error, self).__init__(message)
+        super().__init__(message)
 
         self.uri = uri
         self.state = state
@@ -54,12 +58,21 @@ class OAuth2Error(Exception):
             self.client_id = request.client_id
             self.scopes = request.scopes
             self.response_type = request.response_type
+            self.response_mode = request.response_mode
             self.grant_type = request.grant_type
             if not state:
                 self.state = request.state
+        else:
+            self.redirect_uri = None
+            self.client_id = None
+            self.scopes = None
+            self.response_type = None
+            self.response_mode = None
+            self.grant_type = None
 
     def in_uri(self, uri):
-        return add_params_to_uri(uri, self.twotuples)
+        fragment = self.response_mode == "fragment"
+        return add_params_to_uri(uri, self.twotuples, fragment)
 
     @property
     def twotuples(self):
@@ -80,6 +93,27 @@ class OAuth2Error(Exception):
     def json(self):
         return json.dumps(dict(self.twotuples))
 
+    @property
+    def headers(self):
+        if self.status_code == 401:
+            """
+            https://tools.ietf.org/html/rfc6750#section-3
+
+            All challenges defined by this specification MUST use the auth-scheme
+            value "Bearer".  This scheme MUST be followed by one or more
+            auth-param values.
+            """
+            authvalues = [
+                "Bearer",
+                'error="{}"'.format(self.error)
+            ]
+            if self.description:
+                authvalues.append('error_description="{}"'.format(self.description))
+            if self.uri:
+                authvalues.append('error_uri="{}"'.format(self.uri))
+            return {"WWW-Authenticate": ", ".join(authvalues)}
+        return {}
+
 
 class TokenExpiredError(OAuth2Error):
     error = 'token_expired'
@@ -108,8 +142,8 @@ class MissingTokenTypeError(OAuth2Error):
 
 
 class FatalClientError(OAuth2Error):
-
-    """Errors during authorization where user should not be redirected back.
+    """
+    Errors during authorization where user should not be redirected back.
 
     If the request fails due to a missing, invalid, or mismatching
     redirection URI, or if the client identifier is missing or invalid,
@@ -123,7 +157,8 @@ class FatalClientError(OAuth2Error):
 
 
 class InvalidRequestFatalError(FatalClientError):
-    """For fatal errors, the request is missing a required parameter, includes
+    """
+    For fatal errors, the request is missing a required parameter, includes
     an invalid parameter value, includes a parameter more than once, or is
     otherwise malformed.
     """
@@ -151,8 +186,8 @@ class MissingClientIdError(InvalidRequestFatalError):
 
 
 class InvalidRequestError(OAuth2Error):
-
-    """The request is missing a required parameter, includes an invalid
+    """
+    The request is missing a required parameter, includes an invalid
     parameter value, includes a parameter more than once, or is
     otherwise malformed.
     """
@@ -163,31 +198,66 @@ class MissingResponseTypeError(InvalidRequestError):
     description = 'Missing response_type parameter.'
 
 
-class AccessDeniedError(OAuth2Error):
+class MissingCodeChallengeError(InvalidRequestError):
+    """
+    If the server requires Proof Key for Code Exchange (PKCE) by OAuth
+    public clients and the client does not send the "code_challenge" in
+    the request, the authorization endpoint MUST return the authorization
+    error response with the "error" value set to "invalid_request".  The
+    "error_description" or the response of "error_uri" SHOULD explain the
+    nature of error, e.g., code challenge required.
+    """
+    description = 'Code challenge required.'
 
-    """The resource owner or authorization server denied the request."""
+
+class MissingCodeVerifierError(InvalidRequestError):
+    """
+    The request to the token endpoint, when PKCE is enabled, has
+    the parameter `code_verifier` REQUIRED.
+    """
+    description = 'Code verifier required.'
+
+
+class AccessDeniedError(OAuth2Error):
+    """
+    The resource owner or authorization server denied the request.
+    """
     error = 'access_denied'
-    status_code = 401
 
 
 class UnsupportedResponseTypeError(OAuth2Error):
-
-    """The authorization server does not support obtaining an authorization
+    """
+    The authorization server does not support obtaining an authorization
     code using this method.
     """
     error = 'unsupported_response_type'
 
 
-class InvalidScopeError(OAuth2Error):
+class UnsupportedCodeChallengeMethodError(InvalidRequestError):
+    """
+    If the server supporting PKCE does not support the requested
+    transformation, the authorization endpoint MUST return the
+    authorization error response with "error" value set to
+    "invalid_request".  The "error_description" or the response of
+    "error_uri" SHOULD explain the nature of error, e.g., transform
+    algorithm not supported.
+    """
+    description = 'Transform algorithm not supported.'
 
-    """The requested scope is invalid, unknown, or malformed."""
+
+class InvalidScopeError(OAuth2Error):
+    """
+    The requested scope is invalid, unknown, or malformed, or
+    exceeds the scope granted by the resource owner.
+
+    https://tools.ietf.org/html/rfc6749#section-5.2
+    """
     error = 'invalid_scope'
-    status_code = 401
 
 
 class ServerError(OAuth2Error):
-
-    """The authorization server encountered an unexpected condition that
+    """
+    The authorization server encountered an unexpected condition that
     prevented it from fulfilling the request.  (This error code is needed
     because a 500 Internal Server Error HTTP status code cannot be returned
     to the client via a HTTP redirect.)
@@ -196,8 +266,8 @@ class ServerError(OAuth2Error):
 
 
 class TemporarilyUnavailableError(OAuth2Error):
-
-    """The authorization server is currently unable to handle the request
+    """
+    The authorization server is currently unable to handle the request
     due to a temporary overloading or maintenance of the server.
     (This error code is needed because a 503 Service Unavailable HTTP
     status code cannot be returned to the client via a HTTP redirect.)
@@ -205,9 +275,9 @@ class TemporarilyUnavailableError(OAuth2Error):
     error = 'temporarily_unavailable'
 
 
-class InvalidClientError(OAuth2Error):
-
-    """Client authentication failed (e.g. unknown client, no client
+class InvalidClientError(FatalClientError):
+    """
+    Client authentication failed (e.g. unknown client, no client
     authentication included, or unsupported authentication method).
     The authorization server MAY return an HTTP 401 (Unauthorized) status
     code to indicate which HTTP authentication schemes are supported.
@@ -222,42 +292,103 @@ class InvalidClientError(OAuth2Error):
 
 
 class InvalidGrantError(OAuth2Error):
-
-    """The provided authorization grant (e.g. authorization code, resource
+    """
+    The provided authorization grant (e.g. authorization code, resource
     owner credentials) or refresh token is invalid, expired, revoked, does
     not match the redirection URI used in the authorization request, or was
     issued to another client.
+
+    https://tools.ietf.org/html/rfc6749#section-5.2
     """
     error = 'invalid_grant'
-    status_code = 401
+    status_code = 400
 
 
 class UnauthorizedClientError(OAuth2Error):
-
-    """The authenticated client is not authorized to use this authorization
+    """
+    The authenticated client is not authorized to use this authorization
     grant type.
     """
     error = 'unauthorized_client'
-    status_code = 401
 
 
 class UnsupportedGrantTypeError(OAuth2Error):
-
-    """The authorization grant type is not supported by the authorization
+    """
+    The authorization grant type is not supported by the authorization
     server.
     """
     error = 'unsupported_grant_type'
 
 
 class UnsupportedTokenTypeError(OAuth2Error):
-
-    """The authorization server does not support the revocation of the
+    """
+    The authorization server does not support the hint of the
     presented token type.  I.e. the client tried to revoke an access token
     on a server not supporting this feature.
     """
     error = 'unsupported_token_type'
 
 
+class InvalidTokenError(OAuth2Error):
+    """
+    The access token provided is expired, revoked, malformed, or
+    invalid for other reasons.  The resource SHOULD respond with
+    the HTTP 401 (Unauthorized) status code.  The client MAY
+    request a new access token and retry the protected resource
+    request.
+    """
+    error = 'invalid_token'
+    status_code = 401
+    description = ("The access token provided is expired, revoked, malformed, "
+                   "or invalid for other reasons.")
+
+
+class InsufficientScopeError(OAuth2Error):
+    """
+    The request requires higher privileges than provided by the
+    access token.  The resource server SHOULD respond with the HTTP
+    403 (Forbidden) status code and MAY include the "scope"
+    attribute with the scope necessary to access the protected
+    resource.
+    """
+    error = 'insufficient_scope'
+    status_code = 403
+    description = ("The request requires higher privileges than provided by "
+                   "the access token.")
+
+
+class ConsentRequired(OAuth2Error):
+    """
+    The Authorization Server requires End-User consent.
+
+    This error MAY be returned when the prompt parameter value in the
+    Authentication Request is none, but the Authentication Request cannot be
+    completed without displaying a user interface for End-User consent.
+    """
+    error = 'consent_required'
+
+
+class LoginRequired(OAuth2Error):
+    """
+    The Authorization Server requires End-User authentication.
+
+    This error MAY be returned when the prompt parameter value in the
+    Authentication Request is none, but the Authentication Request cannot be
+    completed without displaying a user interface for End-User authentication.
+    """
+    error = 'login_required'
+
+
+class CustomOAuth2Error(OAuth2Error):
+    """
+    This error is a placeholder for all custom errors not described by the RFC.
+    Some of the popular OAuth2 providers are using custom errors.
+    """
+    def __init__(self, error, *args, **kwargs):
+        self.error = error
+        super().__init__(*args, **kwargs)
+
+
 def raise_from_error(error, params=None):
     import inspect
     import sys
@@ -269,3 +400,4 @@ def raise_from_error(error, params=None):
     for _, cls in inspect.getmembers(sys.modules[__name__], inspect.isclass):
         if cls.error == error:
             raise cls(**kwargs)
+    raise CustomOAuth2Error(error=error, **kwargs)
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/__init__.py b/lib/oauthlib/oauth2/rfc6749/grant_types/__init__.py
index 2ec8e4fa..eb88cfc2 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/__init__.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/__init__.py
@@ -1,12 +1,11 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 from .authorization_code import AuthorizationCodeGrant
-from .implicit import ImplicitGrant
-from .resource_owner_password_credentials import ResourceOwnerPasswordCredentialsGrant
 from .client_credentials import ClientCredentialsGrant
+from .implicit import ImplicitGrant
 from .refresh_token import RefreshTokenGrant
+from .resource_owner_password_credentials import (
+    ResourceOwnerPasswordCredentialsGrant,
+)
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/authorization_code.py b/lib/oauthlib/oauth2/rfc6749/grant_types/authorization_code.py
index 31f06fcd..bf42d889 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/authorization_code.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/authorization_code.py
@@ -1,23 +1,66 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
+import base64
+import hashlib
 import json
 import logging
 
 from oauthlib import common
-from oauthlib.uri_validate import is_absolute_uri
 
-from .base import GrantTypeBase
 from .. import errors
-from ..request_validator import RequestValidator
+from .base import GrantTypeBase
 
 log = logging.getLogger(__name__)
 
 
+def code_challenge_method_s256(verifier, challenge):
+    """
+    If the "code_challenge_method" from `Section 4.3`_ was "S256", the
+    received "code_verifier" is hashed by SHA-256, base64url-encoded, and
+    then compared to the "code_challenge", i.e.:
+
+    BASE64URL-ENCODE(SHA256(ASCII(code_verifier))) == code_challenge
+
+    How to implement a base64url-encoding
+    function without padding, based upon the standard base64-encoding
+    function that uses padding.
+
+    To be concrete, example C# code implementing these functions is shown
+    below.  Similar code could be used in other languages.
+
+    static string base64urlencode(byte [] arg)
+    {
+        string s = Convert.ToBase64String(arg); // Regular base64 encoder
+        s = s.Split('=')[0]; // Remove any trailing '='s
+        s = s.Replace('+', '-'); // 62nd char of encoding
+        s = s.Replace('/', '_'); // 63rd char of encoding
+        return s;
+    }
+
+    In python urlsafe_b64encode is already replacing '+' and '/', but preserve
+    the trailing '='. So we have to remove it.
+
+    .. _`Section 4.3`: https://tools.ietf.org/html/rfc7636#section-4.3
+    """
+    return base64.urlsafe_b64encode(
+        hashlib.sha256(verifier.encode()).digest()
+    ).decode().rstrip('=') == challenge
+
+
+def code_challenge_method_plain(verifier, challenge):
+    """
+    If the "code_challenge_method" from `Section 4.3`_ was "plain", they are
+    compared directly, i.e.:
+
+    code_verifier == code_challenge.
+
+    .. _`Section 4.3`: https://tools.ietf.org/html/rfc7636#section-4.3
+    """
+    return verifier == challenge
+
+
 class AuthorizationCodeGrant(GrantTypeBase):
 
     """`Authorization Code Grant`_
@@ -92,15 +135,35 @@ class AuthorizationCodeGrant(GrantTypeBase):
          step (C).  If valid, the authorization server responds back with
          an access token and, optionally, a refresh token.
 
-    .. _`Authorization Code Grant`: http://tools.ietf.org/html/rfc6749#section-4.1
+    OAuth 2.0 public clients utilizing the Authorization Code Grant are
+    susceptible to the authorization code interception attack.
+
+    A technique to mitigate against the threat through the use of Proof Key for Code
+    Exchange (PKCE, pronounced "pixy") is implemented in the current oauthlib
+    implementation.
+
+    .. _`Authorization Code Grant`: https://tools.ietf.org/html/rfc6749#section-4.1
+    .. _`PKCE`: https://tools.ietf.org/html/rfc7636
     """
 
-    def __init__(self, request_validator=None, refresh_token=True):
-        self.request_validator = request_validator or RequestValidator()
-        self.refresh_token = refresh_token
+    default_response_mode = 'query'
+    response_types = ['code']
+
+    # This dict below is private because as RFC mention it:
+    # "S256" is Mandatory To Implement (MTI) on the server.
+    #
+    _code_challenge_methods = {
+        'plain': code_challenge_method_plain,
+        'S256': code_challenge_method_s256
+    }
 
     def create_authorization_code(self, request):
-        """Generates an authorization grant represented as a dictionary."""
+        """
+        Generates an authorization grant represented as a dictionary.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         grant = {'code': common.generate_token()}
         if hasattr(request, 'state') and request.state:
             grant['state'] = request.state
@@ -115,7 +178,10 @@ class AuthorizationCodeGrant(GrantTypeBase):
         using the "application/x-www-form-urlencoded" format, per `Appendix B`_:
 
         response_type
-                REQUIRED.  Value MUST be set to "code".
+                REQUIRED.  Value MUST be set to "code" for standard OAuth2
+                authorization flow.  For OpenID Connect it must be one of
+                "code token", "code id_token", or "code token id_token" - we
+                essentially test that "code" appears in the response_type.
         client_id
                 REQUIRED.  The client identifier as described in `Section 2.2`_.
         redirect_uri
@@ -134,12 +200,12 @@ class AuthorizationCodeGrant(GrantTypeBase):
         HTTP redirection response, or by other means available to it via the
         user-agent.
 
-        :param request: oauthlib.commong.Request
-        :param token_handler: A token handler instace, for example of type
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
                               oauthlib.oauth2.BearerToken.
         :returns: headers, body, status
         :raises: FatalClientError on invalid redirect URI or client id.
-                 ValueError if scopes are not set on the request object.
 
         A few examples::
 
@@ -150,12 +216,6 @@ class AuthorizationCodeGrant(GrantTypeBase):
             >>> from oauthlib.oauth2 import AuthorizationCodeGrant, BearerToken
             >>> token = BearerToken(your_validator)
             >>> grant = AuthorizationCodeGrant(your_validator)
-            >>> grant.create_authorization_response(request, token)
-            Traceback (most recent call last):
-                File "<stdin>", line 1, in <module>
-                File "oauthlib/oauth2/rfc6749/grant_types.py", line 513, in create_authorization_response
-                    raise ValueError('Scopes must be set on post auth.')
-            ValueError: Scopes must be set on post auth.
             >>> request.scopes = ['authorized', 'in', 'some', 'form']
             >>> grant.create_authorization_response(request, token)
             (u'http://client.com/?error=invalid_request&error_description=Missing+response_type+parameter.', None, None, 400)
@@ -174,18 +234,13 @@ class AuthorizationCodeGrant(GrantTypeBase):
                 File "oauthlib/oauth2/rfc6749/grant_types.py", line 591, in validate_authorization_request
             oauthlib.oauth2.rfc6749.errors.InvalidClientIdError
 
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
-        .. _`Section 2.2`: http://tools.ietf.org/html/rfc6749#section-2.2
-        .. _`Section 3.1.2`: http://tools.ietf.org/html/rfc6749#section-3.1.2
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 10.12`: http://tools.ietf.org/html/rfc6749#section-10.12
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 2.2`: https://tools.ietf.org/html/rfc6749#section-2.2
+        .. _`Section 3.1.2`: https://tools.ietf.org/html/rfc6749#section-3.1.2
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 10.12`: https://tools.ietf.org/html/rfc6749#section-10.12
         """
         try:
-            # request.scopes is only mandated in post auth and both pre and
-            # post auth use validate_authorization_request
-            if not request.scopes:
-                raise ValueError('Scopes must be set on post auth.')
-
             self.validate_authorization_request(request)
             log.debug('Pre resource owner authorization validation ok for %r.',
                       request)
@@ -205,17 +260,23 @@ class AuthorizationCodeGrant(GrantTypeBase):
         # the authorization server informs the client by adding the following
         # parameters to the query component of the redirection URI using the
         # "application/x-www-form-urlencoded" format, per Appendix B:
-        # http://tools.ietf.org/html/rfc6749#appendix-B
+        # https://tools.ietf.org/html/rfc6749#appendix-B
         except errors.OAuth2Error as e:
             log.debug('Client error during validation of %r. %r.', request, e)
             request.redirect_uri = request.redirect_uri or self.error_uri
-            return {'Location': common.add_params_to_uri(request.redirect_uri, e.twotuples)}, None, 302
+            redirect_uri = common.add_params_to_uri(
+                request.redirect_uri, e.twotuples,
+                fragment=request.response_mode == "fragment")
+            return {'Location': redirect_uri}, None, 302
 
         grant = self.create_authorization_code(request)
+        for modifier in self._code_modifiers:
+            grant = modifier(grant, token_handler, request)
         log.debug('Saving grant %r for %r.', grant, request)
         self.request_validator.save_authorization_code(
             request.client_id, grant, request)
-        return {'Location': common.add_params_to_uri(request.redirect_uri, grant.items())}, None, 302
+        return self.prepare_authorization_response(
+            request, grant, {}, None, 302)
 
     def create_token_response(self, request, token_handler):
         """Validate the authorization code.
@@ -225,20 +286,28 @@ class AuthorizationCodeGrant(GrantTypeBase):
         MUST deny the request and SHOULD revoke (when possible) all tokens
         previously issued based on that authorization code. The authorization
         code is bound to the client identifier and redirection URI.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+
         """
-        headers = {
-            'Content-Type': 'application/json',
-            'Cache-Control': 'no-store',
-            'Pragma': 'no-cache',
-        }
+        headers = self._get_default_headers()
         try:
             self.validate_token_request(request)
             log.debug('Token request validation ok for %r.', request)
         except errors.OAuth2Error as e:
             log.debug('Client error during validation of %r. %r.', request, e)
+            headers.update(e.headers)
             return headers, e.json, e.status_code
 
         token = token_handler.create_token(request, refresh_token=self.refresh_token)
+
+        for modifier in self._token_modifiers:
+            token = modifier(token, token_handler, request)
+
+        self.request_validator.save_token(token, request)
         self.request_validator.invalidate_authorization_code(
             request.client_id, request.code, request)
         return headers, json.dumps(token), 200
@@ -255,6 +324,9 @@ class AuthorizationCodeGrant(GrantTypeBase):
         missing. These must be caught by the provider and handled, how this
         is done is outside of the scope of OAuthLib but showing an error
         page describing the issue is a good idea.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         """
 
         # First check for fatal errors
@@ -275,7 +347,7 @@ class AuthorizationCodeGrant(GrantTypeBase):
                 raise errors.InvalidRequestFatalError(description='Duplicate %s parameter.' % param, request=request)
 
         # REQUIRED. The client identifier as described in Section 2.2.
-        # http://tools.ietf.org/html/rfc6749#section-2.2
+        # https://tools.ietf.org/html/rfc6749#section-2.2
         if not request.client_id:
             raise errors.MissingClientIdError(request=request)
 
@@ -283,25 +355,13 @@ class AuthorizationCodeGrant(GrantTypeBase):
             raise errors.InvalidClientIdError(request=request)
 
         # OPTIONAL. As described in Section 3.1.2.
-        # http://tools.ietf.org/html/rfc6749#section-3.1.2
+        # https://tools.ietf.org/html/rfc6749#section-3.1.2
         log.debug('Validating redirection uri %s for client %s.',
                   request.redirect_uri, request.client_id)
-        if request.redirect_uri is not None:
-            request.using_default_redirect_uri = False
-            log.debug('Using provided redirect_uri %s', request.redirect_uri)
-            if not is_absolute_uri(request.redirect_uri):
-                raise errors.InvalidRedirectURIError(request=request)
 
-            if not self.request_validator.validate_redirect_uri(
-                    request.client_id, request.redirect_uri, request):
-                raise errors.MismatchingRedirectURIError(request=request)
-        else:
-            request.redirect_uri = self.request_validator.get_default_redirect_uri(
-                request.client_id, request)
-            request.using_default_redirect_uri = True
-            log.debug('Using default redirect_uri %s.', request.redirect_uri)
-            if not request.redirect_uri:
-                raise errors.MissingRedirectURIError(request=request)
+        # OPTIONAL. As described in Section 3.1.2.
+        # https://tools.ietf.org/html/rfc6749#section-3.1.2
+        self._handle_redirects(request)
 
         # Then check for normal errors.
 
@@ -310,16 +370,21 @@ class AuthorizationCodeGrant(GrantTypeBase):
         # the authorization server informs the client by adding the following
         # parameters to the query component of the redirection URI using the
         # "application/x-www-form-urlencoded" format, per Appendix B.
-        # http://tools.ietf.org/html/rfc6749#appendix-B
+        # https://tools.ietf.org/html/rfc6749#appendix-B
 
         # Note that the correct parameters to be added are automatically
         # populated through the use of specific exceptions.
 
+        request_info = {}
+        for validator in self.custom_validators.pre_auth:
+            request_info.update(validator(request))
+
         # REQUIRED.
         if request.response_type is None:
             raise errors.MissingResponseTypeError(request=request)
-        # Value MUST be set to "code".
-        elif request.response_type != 'code':
+        # Value MUST be set to "code" or one of the OpenID authorization code including
+        # response_types "code token", "code id_token", "code token id_token"
+        elif not 'code' in request.response_type and request.response_type != 'none':
             raise errors.UnsupportedResponseTypeError(request=request)
 
         if not self.request_validator.validate_response_type(request.client_id,
@@ -330,23 +395,52 @@ class AuthorizationCodeGrant(GrantTypeBase):
                       request.client_id, request.response_type)
             raise errors.UnauthorizedClientError(request=request)
 
+        # OPTIONAL. Validate PKCE request or reply with "error"/"invalid_request"
+        # https://tools.ietf.org/html/rfc6749#section-4.4.1
+        if self.request_validator.is_pkce_required(request.client_id, request) is True:
+            if request.code_challenge is None:
+                raise errors.MissingCodeChallengeError(request=request)
+
+        if request.code_challenge is not None:
+            request_info["code_challenge"] = request.code_challenge
+
+            # OPTIONAL, defaults to "plain" if not present in the request.
+            if request.code_challenge_method is None:
+                request.code_challenge_method = "plain"
+
+            if request.code_challenge_method not in self._code_challenge_methods:
+                raise errors.UnsupportedCodeChallengeMethodError(request=request)
+            request_info["code_challenge_method"] = request.code_challenge_method
+
         # OPTIONAL. The scope of the access request as described by Section 3.3
-        # http://tools.ietf.org/html/rfc6749#section-3.3
+        # https://tools.ietf.org/html/rfc6749#section-3.3
         self.validate_scopes(request)
 
-        return request.scopes, {
+        request_info.update({
             'client_id': request.client_id,
             'redirect_uri': request.redirect_uri,
             'response_type': request.response_type,
             'state': request.state,
-            'request': request,
-        }
+            'request': request
+        })
+
+        for validator in self.custom_validators.post_auth:
+            request_info.update(validator(request))
+
+        return request.scopes, request_info
 
     def validate_token_request(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         # REQUIRED. Value MUST be set to "authorization_code".
-        if request.grant_type != 'authorization_code':
+        if request.grant_type not in ('authorization_code', 'openid'):
             raise errors.UnsupportedGrantTypeError(request=request)
 
+        for validator in self.custom_validators.pre_token:
+            validator(request)
+
         if request.code is None:
             raise errors.InvalidRequestError(
                 description='Missing code parameter.', request=request)
@@ -361,14 +455,14 @@ class AuthorizationCodeGrant(GrantTypeBase):
             # credentials (or assigned other authentication requirements), the
             # client MUST authenticate with the authorization server as described
             # in Section 3.2.1.
-            # http://tools.ietf.org/html/rfc6749#section-3.2.1
+            # https://tools.ietf.org/html/rfc6749#section-3.2.1
             if not self.request_validator.authenticate_client(request):
                 log.debug('Client authentication failed, %r.', request)
                 raise errors.InvalidClientError(request=request)
         elif not self.request_validator.authenticate_client_id(request.client_id, request):
             # REQUIRED, if the client is not authenticating with the
             # authorization server as described in Section 3.2.1.
-            # http://tools.ietf.org/html/rfc6749#section-3.2.1
+            # https://tools.ietf.org/html/rfc6749#section-3.2.1
             log.debug('Client authentication failed, %r.', request)
             raise errors.InvalidClientError(request=request)
 
@@ -377,6 +471,8 @@ class AuthorizationCodeGrant(GrantTypeBase):
                                       'request.client.client_id attribute '
                                       'in authenticate_client.')
 
+        request.client_id = request.client_id or request.client.client_id
+
         # Ensure client is authorized use of this grant type
         self.validate_grant_type(request)
 
@@ -388,6 +484,33 @@ class AuthorizationCodeGrant(GrantTypeBase):
                       request.client_id, request.client, request.scopes)
             raise errors.InvalidGrantError(request=request)
 
+        # OPTIONAL. Validate PKCE code_verifier
+        challenge = self.request_validator.get_code_challenge(request.code, request)
+
+        if challenge is not None:
+            if request.code_verifier is None:
+                raise errors.MissingCodeVerifierError(request=request)
+
+            challenge_method = self.request_validator.get_code_challenge_method(request.code, request)
+            if challenge_method is None:
+                raise errors.InvalidGrantError(request=request, description="Challenge method not found")
+
+            if challenge_method not in self._code_challenge_methods:
+                raise errors.ServerError(
+                    description="code_challenge_method {} is not supported.".format(challenge_method),
+                    request=request
+                )
+
+            if not self.validate_code_challenge(challenge,
+                                                challenge_method,
+                                                request.code_verifier):
+                log.debug('request provided a invalid code_verifier.')
+                raise errors.InvalidGrantError(request=request)
+        elif self.request_validator.is_pkce_required(request.client_id, request) is True:
+            if request.code_verifier is None:
+                raise errors.MissingCodeVerifierError(request=request)
+            raise errors.InvalidGrantError(request=request, description="Challenge not found")
+
         for attr in ('user', 'scopes'):
             if getattr(request, attr, None) is None:
                 log.debug('request.%s was not set on code validation.', attr)
@@ -395,8 +518,28 @@ class AuthorizationCodeGrant(GrantTypeBase):
         # REQUIRED, if the "redirect_uri" parameter was included in the
         # authorization request as described in Section 4.1.1, and their
         # values MUST be identical.
+        if request.redirect_uri is None:
+            request.using_default_redirect_uri = True
+            request.redirect_uri = self.request_validator.get_default_redirect_uri(
+                request.client_id, request)
+            log.debug('Using default redirect_uri %s.', request.redirect_uri)
+            if not request.redirect_uri:
+                raise errors.MissingRedirectURIError(request=request)
+        else:
+            request.using_default_redirect_uri = False
+            log.debug('Using provided redirect_uri %s', request.redirect_uri)
+
         if not self.request_validator.confirm_redirect_uri(request.client_id, request.code,
-                                                           request.redirect_uri, request.client):
+                                                           request.redirect_uri, request.client,
+                                                           request):
             log.debug('Redirect_uri (%r) invalid for client %r (%r).',
                       request.redirect_uri, request.client_id, request.client)
-            raise errors.AccessDeniedError(request=request)
+            raise errors.MismatchingRedirectURIError(request=request)
+
+        for validator in self.custom_validators.post_token:
+            validator(request)
+
+    def validate_code_challenge(self, challenge, challenge_method, verifier):
+        if challenge_method in self._code_challenge_methods:
+            return self._code_challenge_methods[challenge_method](verifier, challenge)
+        raise NotImplementedError('Unknown challenge_method %s' % challenge_method)
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/base.py b/lib/oauthlib/oauth2/rfc6749/grant_types/base.py
index 9fc632f0..a64f168c 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/base.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/base.py
@@ -1,28 +1,158 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 import logging
+from itertools import chain
 
+from oauthlib.common import add_params_to_uri
 from oauthlib.oauth2.rfc6749 import errors, utils
+from oauthlib.uri_validate import is_absolute_uri
+
+from ..request_validator import RequestValidator
 
 log = logging.getLogger(__name__)
 
 
-class GrantTypeBase(object):
+class ValidatorsContainer:
+    """
+    Container object for holding custom validator callables to be invoked
+    as part of the grant type `validate_authorization_request()` or
+    `validate_authorization_request()` methods on the various grant types.
+
+    Authorization validators must be callables that take a request object and
+    return a dict, which may contain items to be added to the `request_info`
+    returned from the grant_type after validation.
+
+    Token validators must be callables that take a request object and
+    return None.
+
+    Both authorization validators and token validators may raise OAuth2
+    exceptions if validation conditions fail.
+
+    Authorization validators added to `pre_auth` will be run BEFORE
+    the standard validations (but after the critical ones that raise
+    fatal errors) as part of `validate_authorization_request()`
+
+    Authorization validators added to `post_auth` will be run AFTER
+    the standard validations as part of `validate_authorization_request()`
+
+    Token validators added to `pre_token` will be run BEFORE
+    the standard validations as part of `validate_token_request()`
+
+    Token validators added to `post_token` will be run AFTER
+    the standard validations as part of `validate_token_request()`
+
+    For example:
+
+    >>> def my_auth_validator(request):
+    ...    return {'myval': True}
+    >>> auth_code_grant = AuthorizationCodeGrant(request_validator)
+    >>> auth_code_grant.custom_validators.pre_auth.append(my_auth_validator)
+    >>> def my_token_validator(request):
+    ...     if not request.everything_okay:
+    ...         raise errors.OAuth2Error("uh-oh")
+    >>> auth_code_grant.custom_validators.post_token.append(my_token_validator)
+    """
+
+    def __init__(self, post_auth, post_token,
+                 pre_auth, pre_token):
+        self.pre_auth = pre_auth
+        self.post_auth = post_auth
+        self.pre_token = pre_token
+        self.post_token = post_token
+
+    @property
+    def all_pre(self):
+        return chain(self.pre_auth, self.pre_token)
+
+    @property
+    def all_post(self):
+        return chain(self.post_auth, self.post_token)
+
+
+class GrantTypeBase:
     error_uri = None
     request_validator = None
+    default_response_mode = 'fragment'
+    refresh_token = True
+    response_types = ['code']
+
+    def __init__(self, request_validator=None, **kwargs):
+        self.request_validator = request_validator or RequestValidator()
+
+        # Transforms class variables into instance variables:
+        self.response_types = self.response_types
+        self.refresh_token = self.refresh_token
+        self._setup_custom_validators(kwargs)
+        self._code_modifiers = []
+        self._token_modifiers = []
+
+        for kw, val in kwargs.items():
+            setattr(self, kw, val)
+
+    def _setup_custom_validators(self, kwargs):
+        post_auth = kwargs.get('post_auth', [])
+        post_token = kwargs.get('post_token', [])
+        pre_auth = kwargs.get('pre_auth', [])
+        pre_token = kwargs.get('pre_token', [])
+        if not hasattr(self, 'validate_authorization_request'):
+            if post_auth or pre_auth:
+                msg = ("{} does not support authorization validators. Use "
+                       "token validators instead.").format(self.__class__.__name__)
+                raise ValueError(msg)
+            # Using tuples here because they can't be appended to:
+            post_auth, pre_auth = (), ()
+        self.custom_validators = ValidatorsContainer(post_auth, post_token,
+                                                     pre_auth, pre_token)
+
+    def register_response_type(self, response_type):
+        self.response_types.append(response_type)
+
+    def register_code_modifier(self, modifier):
+        self._code_modifiers.append(modifier)
+
+    def register_token_modifier(self, modifier):
+        self._token_modifiers.append(modifier)
 
     def create_authorization_response(self, request, token_handler):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+        """
         raise NotImplementedError('Subclasses must implement this method.')
 
     def create_token_response(self, request, token_handler):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+        """
         raise NotImplementedError('Subclasses must implement this method.')
 
+    def add_token(self, token, token_handler, request):
+        """
+        :param token:
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
+        # Only add a hybrid access token on auth step if asked for
+        if not request.response_type in ["token", "code token", "id_token token", "code id_token token"]:
+            return token
+
+        token.update(token_handler.create_token(request, refresh_token=False))
+        return token
+
     def validate_grant_type(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         client_id = getattr(request, 'client_id', None)
         if not self.request_validator.validate_grant_type(client_id,
                                                           request.grant_type, request.client, request):
@@ -31,6 +161,10 @@ class GrantTypeBase(object):
             raise errors.UnauthorizedClientError(request=request)
 
     def validate_scopes(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         if not request.scopes:
             request.scopes = utils.scope_to_list(request.scope) or utils.scope_to_list(
                 self.request_validator.get_default_scopes(request.client_id, request))
@@ -39,3 +173,78 @@ class GrantTypeBase(object):
         if not self.request_validator.validate_scopes(request.client_id,
                                                       request.scopes, request.client, request):
             raise errors.InvalidScopeError(request=request)
+
+    def prepare_authorization_response(self, request, token, headers, body, status):
+        """Place token according to response mode.
+
+        Base classes can define a default response mode for their authorization
+        response by overriding the static `default_response_mode` member.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token:
+        :param headers:
+        :param body:
+        :param status:
+        """
+        request.response_mode = request.response_mode or self.default_response_mode
+
+        if request.response_mode not in ('query', 'fragment'):
+            log.debug('Overriding invalid response mode %s with %s',
+                      request.response_mode, self.default_response_mode)
+            request.response_mode = self.default_response_mode
+
+        token_items = token.items()
+
+        if request.response_type == 'none':
+            state = token.get('state', None)
+            if state:
+                token_items = [('state', state)]
+            else:
+                token_items = []
+
+        if request.response_mode == 'query':
+            headers['Location'] = add_params_to_uri(
+                request.redirect_uri, token_items, fragment=False)
+            return headers, body, status
+
+        if request.response_mode == 'fragment':
+            headers['Location'] = add_params_to_uri(
+                request.redirect_uri, token_items, fragment=True)
+            return headers, body, status
+
+        raise NotImplementedError(
+            'Subclasses must set a valid default_response_mode')
+
+    def _get_default_headers(self):
+        """Create default headers for grant responses."""
+        return {
+            'Content-Type': 'application/json',
+            'Cache-Control': 'no-store',
+            'Pragma': 'no-cache',
+        }
+
+    def _handle_redirects(self, request):
+        if request.redirect_uri is not None:
+            request.using_default_redirect_uri = False
+            log.debug('Using provided redirect_uri %s', request.redirect_uri)
+            if not is_absolute_uri(request.redirect_uri):
+                raise errors.InvalidRedirectURIError(request=request)
+
+            # The authorization server MUST verify that the redirection URI
+            # to which it will redirect the access token matches a
+            # redirection URI registered by the client as described in
+            # Section 3.1.2.
+            # https://tools.ietf.org/html/rfc6749#section-3.1.2
+            if not self.request_validator.validate_redirect_uri(
+                    request.client_id, request.redirect_uri, request):
+                raise errors.MismatchingRedirectURIError(request=request)
+        else:
+            request.redirect_uri = self.request_validator.get_default_redirect_uri(
+                request.client_id, request)
+            request.using_default_redirect_uri = True
+            log.debug('Using default redirect_uri %s.', request.redirect_uri)
+            if not request.redirect_uri:
+                raise errors.MissingRedirectURIError(request=request)
+            if not is_absolute_uri(request.redirect_uri):
+                raise errors.InvalidRedirectURIError(request=request)
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/client_credentials.py b/lib/oauthlib/oauth2/rfc6749/grant_types/client_credentials.py
index 49173cca..e7b46189 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/client_credentials.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/client_credentials.py
@@ -1,16 +1,12 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 import json
 import logging
 
-from .base import GrantTypeBase
 from .. import errors
-from ..request_validator import RequestValidator
+from .base import GrantTypeBase
 
 log = logging.getLogger(__name__)
 
@@ -47,42 +43,54 @@ class ClientCredentialsGrant(GrantTypeBase):
     (B)  The authorization server authenticates the client, and if valid,
             issues an access token.
 
-    .. _`Client Credentials Grant`: http://tools.ietf.org/html/rfc6749#section-4.4
+    .. _`Client Credentials Grant`: https://tools.ietf.org/html/rfc6749#section-4.4
     """
 
-    def __init__(self, request_validator=None):
-        self.request_validator = request_validator or RequestValidator()
-
     def create_token_response(self, request, token_handler):
         """Return token or error in JSON format.
 
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+
         If the access token request is valid and authorized, the
         authorization server issues an access token as described in
         `Section 5.1`_.  A refresh token SHOULD NOT be included.  If the request
         failed client authentication or is invalid, the authorization server
         returns an error response as described in `Section 5.2`_.
 
-        .. _`Section 5.1`: http://tools.ietf.org/html/rfc6749#section-5.1
-        .. _`Section 5.2`: http://tools.ietf.org/html/rfc6749#section-5.2
+        .. _`Section 5.1`: https://tools.ietf.org/html/rfc6749#section-5.1
+        .. _`Section 5.2`: https://tools.ietf.org/html/rfc6749#section-5.2
         """
-        headers = {
-            'Content-Type': 'application/json',
-            'Cache-Control': 'no-store',
-            'Pragma': 'no-cache',
-        }
+        headers = self._get_default_headers()
         try:
             log.debug('Validating access token request, %r.', request)
             self.validate_token_request(request)
         except errors.OAuth2Error as e:
             log.debug('Client error in token request. %s.', e)
+            headers.update(e.headers)
             return headers, e.json, e.status_code
 
         token = token_handler.create_token(request, refresh_token=False)
+
+        for modifier in self._token_modifiers:
+            token = modifier(token)
+
+        self.request_validator.save_token(token, request)
+
         log.debug('Issuing token to client id %r (%r), %r.',
                   request.client_id, request.client, token)
         return headers, json.dumps(token), 200
 
     def validate_token_request(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
+        for validator in self.custom_validators.pre_token:
+            validator(request)
+
         if not getattr(request, 'grant_type', None):
             raise errors.InvalidRequestError('Request is missing grant type.',
                                              request=request)
@@ -107,6 +115,9 @@ class ClientCredentialsGrant(GrantTypeBase):
         # Ensure client is authorized use of this grant type
         self.validate_grant_type(request)
 
-        log.debug('Authorizing access to user %r.', request.user)
         request.client_id = request.client_id or request.client.client_id
+        log.debug('Authorizing access to client %r.', request.client_id)
         self.validate_scopes(request)
+
+        for validator in self.custom_validators.post_token:
+            validator(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/implicit.py b/lib/oauthlib/oauth2/rfc6749/grant_types/implicit.py
index 2a92a026..6110b6f3 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/implicit.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/implicit.py
@@ -1,18 +1,13 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 import logging
 
 from oauthlib import common
-from oauthlib.uri_validate import is_absolute_uri
 
-from .base import GrantTypeBase
 from .. import errors
-from ..request_validator import RequestValidator
+from .base import GrantTypeBase
 
 log = logging.getLogger(__name__)
 
@@ -112,22 +107,29 @@ class ImplicitGrant(GrantTypeBase):
     See `Section 10.3`_ and `Section 10.16`_ for important security considerations
     when using the implicit grant.
 
-    .. _`Implicit Grant`: http://tools.ietf.org/html/rfc6749#section-4.2
-    .. _`Section 10.3`: http://tools.ietf.org/html/rfc6749#section-10.3
-    .. _`Section 10.16`: http://tools.ietf.org/html/rfc6749#section-10.16
+    .. _`Implicit Grant`: https://tools.ietf.org/html/rfc6749#section-4.2
+    .. _`Section 10.3`: https://tools.ietf.org/html/rfc6749#section-10.3
+    .. _`Section 10.16`: https://tools.ietf.org/html/rfc6749#section-10.16
     """
 
-    def __init__(self, request_validator=None):
-        self.request_validator = request_validator or RequestValidator()
+    response_types = ['token']
+    grant_allows_refresh_token = False
 
     def create_authorization_response(self, request, token_handler):
         """Create an authorization response.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+
         The client constructs the request URI by adding the following
         parameters to the query component of the authorization endpoint URI
         using the "application/x-www-form-urlencoded" format, per `Appendix B`_:
 
         response_type
-                REQUIRED.  Value MUST be set to "token".
+                REQUIRED.  Value MUST be set to "token" for standard OAuth2 implicit flow
+                           or "id_token token" or just "id_token" for OIDC implicit flow
 
         client_id
                 REQUIRED.  The client identifier as described in `Section 2.2`_.
@@ -152,17 +154,22 @@ class ImplicitGrant(GrantTypeBase):
         access token matches a redirection URI registered by the client as
         described in `Section 3.1.2`_.
 
-        .. _`Section 2.2`: http://tools.ietf.org/html/rfc6749#section-2.2
-        .. _`Section 3.1.2`: http://tools.ietf.org/html/rfc6749#section-3.1.2
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 10.12`: http://tools.ietf.org/html/rfc6749#section-10.12
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 2.2`: https://tools.ietf.org/html/rfc6749#section-2.2
+        .. _`Section 3.1.2`: https://tools.ietf.org/html/rfc6749#section-3.1.2
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 10.12`: https://tools.ietf.org/html/rfc6749#section-10.12
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
         """
         return self.create_token_response(request, token_handler)
 
     def create_token_response(self, request, token_handler):
         """Return token or error embedded in the URI fragment.
 
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+
         If the resource owner grants the access request, the authorization
         server issues an access token and delivers it to the client by adding
         the following parameters to the fragment component of the redirection
@@ -195,16 +202,11 @@ class ImplicitGrant(GrantTypeBase):
 
         The authorization server MUST NOT issue a refresh token.
 
-        .. _`Appendix B`: http://tools.ietf.org/html/rfc6749#appendix-B
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 7.1`: http://tools.ietf.org/html/rfc6749#section-7.1
+        .. _`Appendix B`: https://tools.ietf.org/html/rfc6749#appendix-B
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 7.1`: https://tools.ietf.org/html/rfc6749#section-7.1
         """
         try:
-            # request.scopes is only mandated in post auth and both pre and
-            # post auth use validate_authorization_request
-            if not request.scopes:
-                raise ValueError('Scopes must be set on post auth.')
-
             self.validate_token_request(request)
 
         # If the request fails due to a missing, invalid, or mismatching
@@ -222,22 +224,47 @@ class ImplicitGrant(GrantTypeBase):
         # the authorization server informs the client by adding the following
         # parameters to the fragment component of the redirection URI using the
         # "application/x-www-form-urlencoded" format, per Appendix B:
-        # http://tools.ietf.org/html/rfc6749#appendix-B
+        # https://tools.ietf.org/html/rfc6749#appendix-B
         except errors.OAuth2Error as e:
             log.debug('Client error during validation of %r. %r.', request, e)
             return {'Location': common.add_params_to_uri(request.redirect_uri, e.twotuples,
                                                          fragment=True)}, None, 302
 
-        token = token_handler.create_token(request, refresh_token=False)
-        return {'Location': common.add_params_to_uri(request.redirect_uri, token.items(),
-                                                     fragment=True)}, None, 302
+        # In OIDC implicit flow it is possible to have a request_type that does not include the access_token!
+        # "id_token token" - return the access token and the id token
+        # "id_token" - don't return the access token
+        if "token" in request.response_type.split():
+            token = token_handler.create_token(request, refresh_token=False)
+        else:
+            token = {}
+
+        if request.state is not None:
+            token['state'] = request.state
+
+        for modifier in self._token_modifiers:
+            token = modifier(token, token_handler, request)
+
+        # In OIDC implicit flow it is possible to have a request_type that does
+        # not include the access_token! In this case there is no need to save a token.
+        if "token" in request.response_type.split():
+            self.request_validator.save_token(token, request)
+
+        return self.prepare_authorization_response(
+            request, token, {}, None, 302)
 
     def validate_authorization_request(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         return self.validate_token_request(request)
 
     def validate_token_request(self, request):
         """Check the token request for normal and fatal errors.
 
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+
         This method is very similar to validate_authorization_request in
         the AuthorizationCodeGrant but differ in a few subtle areas.
 
@@ -270,7 +297,7 @@ class ImplicitGrant(GrantTypeBase):
                 raise errors.InvalidRequestFatalError(description='Duplicate %s parameter.' % param, request=request)
 
         # REQUIRED. The client identifier as described in Section 2.2.
-        # http://tools.ietf.org/html/rfc6749#section-2.2
+        # https://tools.ietf.org/html/rfc6749#section-2.2
         if not request.client_id:
             raise errors.MissingClientIdError(request=request)
 
@@ -278,39 +305,20 @@ class ImplicitGrant(GrantTypeBase):
             raise errors.InvalidClientIdError(request=request)
 
         # OPTIONAL. As described in Section 3.1.2.
-        # http://tools.ietf.org/html/rfc6749#section-3.1.2
-        if request.redirect_uri is not None:
-            request.using_default_redirect_uri = False
-            log.debug('Using provided redirect_uri %s', request.redirect_uri)
-            if not is_absolute_uri(request.redirect_uri):
-                raise errors.InvalidRedirectURIError(request=request)
-
-            # The authorization server MUST verify that the redirection URI
-            # to which it will redirect the access token matches a
-            # redirection URI registered by the client as described in
-            # Section 3.1.2.
-            # http://tools.ietf.org/html/rfc6749#section-3.1.2
-            if not self.request_validator.validate_redirect_uri(
-                    request.client_id, request.redirect_uri, request):
-                raise errors.MismatchingRedirectURIError(request=request)
-        else:
-            request.redirect_uri = self.request_validator.get_default_redirect_uri(
-                request.client_id, request)
-            request.using_default_redirect_uri = True
-            log.debug('Using default redirect_uri %s.', request.redirect_uri)
-            if not request.redirect_uri:
-                raise errors.MissingRedirectURIError(request=request)
-            if not is_absolute_uri(request.redirect_uri):
-                raise errors.InvalidRedirectURIError(request=request)
+        # https://tools.ietf.org/html/rfc6749#section-3.1.2
+        self._handle_redirects(request)
 
         # Then check for normal errors.
 
+        request_info = self._run_custom_validators(request,
+                                                   self.custom_validators.all_pre)
+
         # If the resource owner denies the access request or if the request
         # fails for reasons other than a missing or invalid redirection URI,
         # the authorization server informs the client by adding the following
         # parameters to the fragment component of the redirection URI using the
         # "application/x-www-form-urlencoded" format, per Appendix B.
-        # http://tools.ietf.org/html/rfc6749#appendix-B
+        # https://tools.ietf.org/html/rfc6749#appendix-B
 
         # Note that the correct parameters to be added are automatically
         # populated through the use of specific exceptions
@@ -318,8 +326,8 @@ class ImplicitGrant(GrantTypeBase):
         # REQUIRED.
         if request.response_type is None:
             raise errors.MissingResponseTypeError(request=request)
-        # Value MUST be set to "token".
-        elif request.response_type != 'token':
+        # Value MUST be one of our registered types: "token" by default or if using OIDC "id_token" or "id_token token"
+        elif not set(request.response_type.split()).issubset(self.response_types):
             raise errors.UnsupportedResponseTypeError(request=request)
 
         log.debug('Validating use of response_type token for client %r (%r).',
@@ -333,13 +341,36 @@ class ImplicitGrant(GrantTypeBase):
             raise errors.UnauthorizedClientError(request=request)
 
         # OPTIONAL. The scope of the access request as described by Section 3.3
-        # http://tools.ietf.org/html/rfc6749#section-3.3
+        # https://tools.ietf.org/html/rfc6749#section-3.3
         self.validate_scopes(request)
 
-        return request.scopes, {
+        request_info.update({
             'client_id': request.client_id,
             'redirect_uri': request.redirect_uri,
             'response_type': request.response_type,
             'state': request.state,
             'request': request,
-        }
+        })
+
+        request_info = self._run_custom_validators(
+            request,
+            self.custom_validators.all_post,
+            request_info
+        )
+
+        return request.scopes, request_info
+
+    def _run_custom_validators(self,
+                               request,
+                               validations,
+                               request_info=None):
+        # Make a copy so we don't modify the existing request_info dict
+        request_info = {} if request_info is None else request_info.copy()
+        # For implicit grant, auth_validators and token_validators are
+        # basically equivalent since the token is returned from the
+        # authorization endpoint.
+        for validator in validations:
+            result = validator(request)
+            if result is not None:
+                request_info.update(result)
+        return request_info
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/refresh_token.py b/lib/oauthlib/oauth2/rfc6749/grant_types/refresh_token.py
index 9ecfe633..8698a3d5 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/refresh_token.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/refresh_token.py
@@ -1,16 +1,12 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 import json
 import logging
 
-from .base import GrantTypeBase
 from .. import errors, utils
-from ..request_validator import RequestValidator
+from .base import GrantTypeBase
 
 log = logging.getLogger(__name__)
 
@@ -19,16 +15,25 @@ class RefreshTokenGrant(GrantTypeBase):
 
     """`Refresh token grant`_
 
-    .. _`Refresh token grant`: http://tools.ietf.org/html/rfc6749#section-6
+    .. _`Refresh token grant`: https://tools.ietf.org/html/rfc6749#section-6
     """
 
-    def __init__(self, request_validator=None, issue_new_refresh_tokens=True):
-        self.request_validator = request_validator or RequestValidator()
-        self.issue_new_refresh_tokens = issue_new_refresh_tokens
+    def __init__(self, request_validator=None,
+                 issue_new_refresh_tokens=True,
+                 **kwargs):
+        super().__init__(
+            request_validator,
+            issue_new_refresh_tokens=issue_new_refresh_tokens,
+            **kwargs)
 
     def create_token_response(self, request, token_handler):
         """Create a new access token from a refresh_token.
 
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+
         If valid and authorized, the authorization server issues an access
         token as described in `Section 5.1`_. If the request failed
         verification or is invalid, the authorization server returns an error
@@ -42,31 +47,42 @@ class RefreshTokenGrant(GrantTypeBase):
         identical to that of the refresh token included by the client in the
         request.
 
-        .. _`Section 5.1`: http://tools.ietf.org/html/rfc6749#section-5.1
-        .. _`Section 5.2`: http://tools.ietf.org/html/rfc6749#section-5.2
+        .. _`Section 5.1`: https://tools.ietf.org/html/rfc6749#section-5.1
+        .. _`Section 5.2`: https://tools.ietf.org/html/rfc6749#section-5.2
         """
-        headers = {
-            'Content-Type': 'application/json',
-            'Cache-Control': 'no-store',
-            'Pragma': 'no-cache',
-        }
+        headers = self._get_default_headers()
         try:
             log.debug('Validating refresh token request, %r.', request)
             self.validate_token_request(request)
         except errors.OAuth2Error as e:
+            log.debug('Client error in token request, %s.', e)
+            headers.update(e.headers)
             return headers, e.json, e.status_code
 
         token = token_handler.create_token(request,
                                            refresh_token=self.issue_new_refresh_tokens)
+
+        for modifier in self._token_modifiers:
+            token = modifier(token)
+
+        self.request_validator.save_token(token, request)
+
         log.debug('Issuing new token to client id %r (%r), %r.',
                   request.client_id, request.client, token)
         return headers, json.dumps(token), 200
 
     def validate_token_request(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         # REQUIRED. Value MUST be set to "refresh_token".
         if request.grant_type != 'refresh_token':
             raise errors.UnsupportedGrantTypeError(request=request)
 
+        for validator in self.custom_validators.pre_token:
+            validator(request)
+
         if request.refresh_token is None:
             raise errors.InvalidRequestError(
                 description='Missing refresh token parameter.',
@@ -78,7 +94,7 @@ class RefreshTokenGrant(GrantTypeBase):
         # the client was issued client credentials (or assigned other
         # authentication requirements), the client MUST authenticate with the
         # authorization server as described in Section 3.2.1.
-        # http://tools.ietf.org/html/rfc6749#section-3.2.1
+        # https://tools.ietf.org/html/rfc6749#section-3.2.1
         if self.request_validator.client_authentication_required(request):
             log.debug('Authenticating client, %r.', request)
             if not self.request_validator.authenticate_client(request):
@@ -106,7 +122,7 @@ class RefreshTokenGrant(GrantTypeBase):
 
         if request.scope:
             request.scopes = utils.scope_to_list(request.scope)
-            if (not all((s in original_scopes for s in request.scopes))
+            if (not all(s in original_scopes for s in request.scopes)
                 and not self.request_validator.is_within_original_scope(
                     request.scopes, request.refresh_token, request)):
                 log.debug('Refresh token %s lack requested scopes, %r.',
@@ -114,3 +130,6 @@ class RefreshTokenGrant(GrantTypeBase):
                 raise errors.InvalidScopeError(request=request)
         else:
             request.scopes = original_scopes
+
+        for validator in self.custom_validators.post_token:
+            validator(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/grant_types/resource_owner_password_credentials.py b/lib/oauthlib/oauth2/rfc6749/grant_types/resource_owner_password_credentials.py
index 51b73741..4b0de5bf 100644
--- a/lib/oauthlib/oauth2/rfc6749/grant_types/resource_owner_password_credentials.py
+++ b/lib/oauthlib/oauth2/rfc6749/grant_types/resource_owner_password_credentials.py
@@ -1,16 +1,12 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.grant_types
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 import json
 import logging
 
-from .base import GrantTypeBase
 from .. import errors
-from ..request_validator import RequestValidator
+from .base import GrantTypeBase
 
 log = logging.getLogger(__name__)
 
@@ -67,34 +63,27 @@ class ResourceOwnerPasswordCredentialsGrant(GrantTypeBase):
             the resource owner credentials, and if valid, issues an access
             token.
 
-    .. _`Resource Owner Password Credentials Grant`: http://tools.ietf.org/html/rfc6749#section-4.3
+    .. _`Resource Owner Password Credentials Grant`: https://tools.ietf.org/html/rfc6749#section-4.3
     """
 
-    def __init__(self, request_validator=None, refresh_token=True):
-        """
-        If the refresh_token keyword argument is False, do not return
-        a refresh token in the response.
-        """
-        self.request_validator = request_validator or RequestValidator()
-        self.refresh_token = refresh_token
-
     def create_token_response(self, request, token_handler):
         """Return token or error in json format.
 
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param token_handler: A token handler instance, for example of type
+                              oauthlib.oauth2.BearerToken.
+
         If the access token request is valid and authorized, the
         authorization server issues an access token and optional refresh
         token as described in `Section 5.1`_.  If the request failed client
         authentication or is invalid, the authorization server returns an
         error response as described in `Section 5.2`_.
 
-        .. _`Section 5.1`: http://tools.ietf.org/html/rfc6749#section-5.1
-        .. _`Section 5.2`: http://tools.ietf.org/html/rfc6749#section-5.2
+        .. _`Section 5.1`: https://tools.ietf.org/html/rfc6749#section-5.1
+        .. _`Section 5.2`: https://tools.ietf.org/html/rfc6749#section-5.2
         """
-        headers = {
-            'Content-Type': 'application/json',
-            'Cache-Control': 'no-store',
-            'Pragma': 'no-cache',
-        }
+        headers = self._get_default_headers()
         try:
             if self.request_validator.client_authentication_required(request):
                 log.debug('Authenticating client, %r.', request)
@@ -108,15 +97,25 @@ class ResourceOwnerPasswordCredentialsGrant(GrantTypeBase):
             self.validate_token_request(request)
         except errors.OAuth2Error as e:
             log.debug('Client error in token request, %s.', e)
+            headers.update(e.headers)
             return headers, e.json, e.status_code
 
         token = token_handler.create_token(request, self.refresh_token)
+
+        for modifier in self._token_modifiers:
+            token = modifier(token)
+
+        self.request_validator.save_token(token, request)
+
         log.debug('Issuing token %r to client id %r (%r) and username %s.',
                   token, request.client_id, request.client, request.username)
         return headers, json.dumps(token), 200
 
     def validate_token_request(self, request):
         """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+
         The client makes a request to the token endpoint by adding the
         following parameters using the "application/x-www-form-urlencoded"
         format per Appendix B with a character encoding of UTF-8 in the HTTP
@@ -156,9 +155,12 @@ class ResourceOwnerPasswordCredentialsGrant(GrantTypeBase):
         brute force attacks (e.g., using rate-limitation or generating
         alerts).
 
-        .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-        .. _`Section 3.2.1`: http://tools.ietf.org/html/rfc6749#section-3.2.1
+        .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+        .. _`Section 3.2.1`: https://tools.ietf.org/html/rfc6749#section-3.2.1
         """
+        for validator in self.custom_validators.pre_token:
+            validator(request)
+
         for param in ('grant_type', 'username', 'password'):
             if not getattr(request, param, None):
                 raise errors.InvalidRequestError(
@@ -192,3 +194,6 @@ class ResourceOwnerPasswordCredentialsGrant(GrantTypeBase):
         if request.client:
             request.client_id = request.client_id or request.client.client_id
         self.validate_scopes(request)
+
+        for validator in self.custom_validators.post_token:
+            validator(request)
diff --git a/lib/oauthlib/oauth2/rfc6749/parameters.py b/lib/oauthlib/oauth2/rfc6749/parameters.py
index b46889ce..f07b8bd2 100644
--- a/lib/oauthlib/oauth2/rfc6749/parameters.py
+++ b/lib/oauthlib/oauth2/rfc6749/parameters.py
@@ -1,28 +1,25 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.oauth2.rfc6749.parameters
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 This module contains methods related to `Section 4`_ of the OAuth 2 RFC.
 
-.. _`Section 4`: http://tools.ietf.org/html/rfc6749#section-4
+.. _`Section 4`: https://tools.ietf.org/html/rfc6749#section-4
 """
-from __future__ import absolute_import, unicode_literals
-
 import json
 import os
 import time
-try:
-    import urlparse
-except ImportError:
-    import urllib.parse as urlparse
-from oauthlib.common import add_params_to_uri, add_params_to_qs, unicode_type
+import urllib.parse as urlparse
+
+from oauthlib.common import add_params_to_qs, add_params_to_uri
 from oauthlib.signals import scope_changed
-from .errors import raise_from_error, MissingTokenError, MissingTokenTypeError
-from .errors import MismatchingStateError, MissingCodeError
-from .errors import InsecureTransportError
+
+from .errors import (
+    InsecureTransportError, MismatchingStateError, MissingCodeError,
+    MissingTokenError, MissingTokenTypeError, raise_from_error,
+)
 from .tokens import OAuth2Token
-from .utils import list_to_scope, scope_to_list, is_secure_transport
+from .utils import is_secure_transport, list_to_scope, scope_to_list
 
 
 def prepare_grant_uri(uri, client_id, response_type, redirect_uri=None,
@@ -34,14 +31,14 @@ def prepare_grant_uri(uri, client_id, response_type, redirect_uri=None,
     using the ``application/x-www-form-urlencoded`` format as defined by
     [`W3C.REC-html401-19991224`_]:
 
+    :param uri:
+    :param client_id: The client identifier as described in `Section 2.2`_.
     :param response_type: To indicate which OAuth 2 grant/flow is required,
                           "code" and "token".
-    :param client_id: The client identifier as described in `Section 2.2`_.
     :param redirect_uri: The client provided URI to redirect back to after
                          authorization as described in `Section 3.1.2`_.
     :param scope: The scope of the access request as described by
                   `Section 3.3`_.
-
     :param state: An opaque value used by the client to maintain
                   state between the request and callback.  The authorization
                   server includes this value when redirecting the user-agent
@@ -58,11 +55,11 @@ def prepare_grant_uri(uri, client_id, response_type, redirect_uri=None,
             &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
         Host: server.example.com
 
-    .. _`W3C.REC-html401-19991224`: http://tools.ietf.org/html/rfc6749#ref-W3C.REC-html401-19991224
-    .. _`Section 2.2`: http://tools.ietf.org/html/rfc6749#section-2.2
-    .. _`Section 3.1.2`: http://tools.ietf.org/html/rfc6749#section-3.1.2
-    .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-    .. _`section 10.12`: http://tools.ietf.org/html/rfc6749#section-10.12
+    .. _`W3C.REC-html401-19991224`: https://tools.ietf.org/html/rfc6749#ref-W3C.REC-html401-19991224
+    .. _`Section 2.2`: https://tools.ietf.org/html/rfc6749#section-2.2
+    .. _`Section 3.1.2`: https://tools.ietf.org/html/rfc6749#section-3.1.2
+    .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+    .. _`section 10.12`: https://tools.ietf.org/html/rfc6749#section-10.12
     """
     if not is_secure_transport(uri):
         raise InsecureTransportError()
@@ -79,12 +76,12 @@ def prepare_grant_uri(uri, client_id, response_type, redirect_uri=None,
 
     for k in kwargs:
         if kwargs[k]:
-            params.append((unicode_type(k), kwargs[k]))
+            params.append((str(k), kwargs[k]))
 
     return add_params_to_uri(uri, params)
 
 
-def prepare_token_request(grant_type, body='', **kwargs):
+def prepare_token_request(grant_type, body='', include_client_id=True, **kwargs):
     """Prepare the access token request.
 
     The client makes a request to the token endpoint by adding the
@@ -92,15 +89,39 @@ def prepare_token_request(grant_type, body='', **kwargs):
     format in the HTTP request entity-body:
 
     :param grant_type: To indicate grant type being used, i.e. "password",
-            "authorization_code" or "client_credentials".
-    :param body: Existing request body to embed parameters in.
-    :param code: If using authorization code grant, pass the previously
-                 obtained authorization code as the ``code`` argument.
+                       "authorization_code" or "client_credentials".
+
+    :param body: Existing request body (URL encoded string) to embed parameters
+                 into. This may contain extra parameters. Default ''.
+
+    :param include_client_id: `True` (default) to send the `client_id` in the
+                              body of the upstream request. This is required
+                              if the client is not authenticating with the
+                              authorization server as described in
+                              `Section 3.2.1`_.
+    :type include_client_id: Boolean
+
+    :param client_id: Unicode client identifier. Will only appear if
+                      `include_client_id` is True. *
+
+    :param client_secret: Unicode client secret. Will only appear if set to a
+                          value that is not `None`. Invoking this function with
+                          an empty string will send an empty `client_secret`
+                          value to the server. *
+
+    :param code: If using authorization_code grant, pass the previously
+                 obtained authorization code as the ``code`` argument. *
+
     :param redirect_uri: If the "redirect_uri" parameter was included in the
                          authorization request as described in
-                         `Section 4.1.1`_, and their values MUST be identical.
+                         `Section 4.1.1`_, and their values MUST be identical. *
+
     :param kwargs: Extra arguments to embed in the request body.
 
+    Parameters marked with a `*` above are not explicit arguments in the
+    function signature, but are specially documented arguments for items
+    appearing in the generic `**kwargs` keyworded input.
+
     An example of an authorization code token request body:
 
     .. code-block:: http
@@ -108,16 +129,29 @@ def prepare_token_request(grant_type, body='', **kwargs):
         grant_type=authorization_code&code=SplxlOBeZQQYbYS6WxSbIA
         &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
 
-    .. _`Section 4.1.1`: http://tools.ietf.org/html/rfc6749#section-4.1.1
+    .. _`Section 4.1.1`: https://tools.ietf.org/html/rfc6749#section-4.1.1
     """
     params = [('grant_type', grant_type)]
 
     if 'scope' in kwargs:
         kwargs['scope'] = list_to_scope(kwargs['scope'])
 
+    # pull the `client_id` out of the kwargs.
+    client_id = kwargs.pop('client_id', None)
+    if include_client_id:
+        if client_id is not None:
+            params.append(('client_id', client_id))
+
+    # the kwargs iteration below only supports including boolean truth (truthy)
+    # values, but some servers may require an empty string for `client_secret`
+    client_secret = kwargs.pop('client_secret', None)
+    if client_secret is not None:
+        params.append(('client_secret', client_secret))
+
+    # this handles: `code`, `redirect_uri`, and other undocumented params
     for k in kwargs:
         if kwargs[k]:
-            params.append((unicode_type(k), kwargs[k]))
+            params.append((str(k), kwargs[k]))
 
     return add_params_to_qs(body, params)
 
@@ -127,18 +161,22 @@ def prepare_token_revocation_request(url, token, token_type_hint="access_token",
     """Prepare a token revocation request.
 
     The client constructs the request by including the following parameters
-    using the "application/x-www-form-urlencoded" format in the HTTP request
+    using the ``application/x-www-form-urlencoded`` format in the HTTP request
     entity-body:
 
-    token   REQUIRED.  The token that the client wants to get revoked.
+    :param token: REQUIRED.  The token that the client wants to get revoked.
 
-    token_type_hint  OPTIONAL.  A hint about the type of the token submitted
-    for revocation.  Clients MAY pass this parameter in order to help the
-    authorization server to optimize the token lookup.  If the server is unable
-    to locate the token using the given hint, it MUST extend its search across
-    all of its supported token types.  An authorization server MAY ignore this
-    parameter, particularly if it is able to detect the token type
-    automatically.  This specification defines two such values:
+    :param token_type_hint: OPTIONAL.  A hint about the type of the token
+                            submitted for revocation. Clients MAY pass this
+                            parameter in order to help the authorization server
+                            to optimize the token lookup.  If the server is
+                            unable to locate the token using the given hint, it
+                            MUST extend its search across all of its supported
+                            token types.  An authorization server MAY ignore
+                            this parameter, particularly if it is able to detect
+                            the token type automatically.
+
+    This specification defines two values for `token_type_hint`:
 
         * access_token: An access token as defined in [RFC6749],
              `Section 1.4`_
@@ -150,9 +188,9 @@ def prepare_token_revocation_request(url, token, token_type_hint="access_token",
         specification MAY define other values for this parameter using the
         registry defined in `Section 4.1.2`_.
 
-    .. _`Section 1.4`: http://tools.ietf.org/html/rfc6749#section-1.4
-    .. _`Section 1.5`: http://tools.ietf.org/html/rfc6749#section-1.5
-    .. _`Section 4.1.2`: http://tools.ietf.org/html/rfc7009#section-4.1.2
+    .. _`Section 1.4`: https://tools.ietf.org/html/rfc6749#section-1.4
+    .. _`Section 1.5`: https://tools.ietf.org/html/rfc6749#section-1.5
+    .. _`Section 4.1.2`: https://tools.ietf.org/html/rfc7009#section-4.1.2
 
     """
     if not is_secure_transport(url):
@@ -165,7 +203,7 @@ def prepare_token_revocation_request(url, token, token_type_hint="access_token",
 
     for k in kwargs:
         if kwargs[k]:
-            params.append((unicode_type(k), kwargs[k]))
+            params.append((str(k), kwargs[k]))
 
     headers = {'Content-Type': 'application/x-www-form-urlencoded'}
 
@@ -220,12 +258,15 @@ def parse_authorization_code_response(uri, state=None):
     query = urlparse.urlparse(uri).query
     params = dict(urlparse.parse_qsl(query))
 
-    if not 'code' in params:
-        raise MissingCodeError("Missing code parameter in response.")
-
     if state and params.get('state', None) != state:
         raise MismatchingStateError()
 
+    if 'error' in params:
+        raise_from_error(params.get('error'), params)
+
+    if not 'code' in params:
+        raise MissingCodeError("Missing code parameter in response.")
+
     return params
 
 
@@ -261,6 +302,10 @@ def parse_implicit_response(uri, state=None, scope=None):
             authorization request.  The exact value received from the
             client.
 
+    :param uri:
+    :param state:
+    :param scope:
+
     Similar to the authorization code response, but with a full token provided
     in the URL fragment:
 
@@ -276,6 +321,10 @@ def parse_implicit_response(uri, state=None, scope=None):
     fragment = urlparse.urlparse(uri).fragment
     params = dict(urlparse.parse_qsl(fragment, keep_blank_values=True))
 
+    for key in ('expires_in',):
+        if key in params:  # cast things to int
+            params[key] = int(params[key])
+
     if 'scope' in params:
         params['scope'] = scope_to_list(params['scope'])
 
@@ -345,10 +394,10 @@ def parse_token_response(body, scope=None):
             "example_parameter":"example_value"
         }
 
-    .. _`Section 7.1`: http://tools.ietf.org/html/rfc6749#section-7.1
-    .. _`Section 6`: http://tools.ietf.org/html/rfc6749#section-6
-    .. _`Section 3.3`: http://tools.ietf.org/html/rfc6749#section-3.3
-    .. _`RFC4627`: http://tools.ietf.org/html/rfc4627
+    .. _`Section 7.1`: https://tools.ietf.org/html/rfc6749#section-7.1
+    .. _`Section 6`: https://tools.ietf.org/html/rfc6749#section-6
+    .. _`Section 3.3`: https://tools.ietf.org/html/rfc6749#section-3.3
+    .. _`RFC4627`: https://tools.ietf.org/html/rfc4627
     """
     try:
         params = json.loads(body)
@@ -356,21 +405,21 @@ def parse_token_response(body, scope=None):
 
         # Fall back to URL-encoded string, to support old implementations,
         # including (at time of writing) Facebook. See:
-        #   https://github.com/idan/oauthlib/issues/267
+        #   https://github.com/oauthlib/oauthlib/issues/267
 
         params = dict(urlparse.parse_qsl(body))
-        for key in ('expires_in', 'expires'):
-            if key in params:  # cast a couple things to int
+        for key in ('expires_in',):
+            if key in params:  # cast things to int
                 params[key] = int(params[key])
 
     if 'scope' in params:
         params['scope'] = scope_to_list(params['scope'])
 
-    if 'expires' in params:
-        params['expires_in'] = params.pop('expires')
-
     if 'expires_in' in params:
-        params['expires_at'] = time.time() + int(params['expires_in'])
+        if params['expires_in'] is None:
+            params.pop('expires_in')
+        else:
+            params['expires_at'] = time.time() + int(params['expires_in'])
 
     params = OAuth2Token(params, old_scope=scope)
     validate_token_parameters(params)
@@ -378,7 +427,7 @@ def parse_token_response(body, scope=None):
 
 
 def validate_token_parameters(params):
-    """Ensures token precence, token type, expiration and scope in params."""
+    """Ensures token presence, token type, expiration and scope in params."""
     if 'error' in params:
         raise_from_error(params.get('error'), params)
 
@@ -392,7 +441,7 @@ def validate_token_parameters(params):
     # If the issued access token scope is different from the one requested by
     # the client, the authorization server MUST include the "scope" response
     # parameter to inform the client of the actual scope granted.
-    # http://tools.ietf.org/html/rfc6749#section-3.3
+    # https://tools.ietf.org/html/rfc6749#section-3.3
     if params.scope_changed:
         message = 'Scope has changed from "{old}" to "{new}".'.format(
             old=params.old_scope, new=params.scope,
diff --git a/lib/oauthlib/oauth2/rfc6749/request_validator.py b/lib/oauthlib/oauth2/rfc6749/request_validator.py
index 442b2a8a..817d594b 100644
--- a/lib/oauthlib/oauth2/rfc6749/request_validator.py
+++ b/lib/oauthlib/oauth2/rfc6749/request_validator.py
@@ -1,16 +1,13 @@
-# -*- coding: utf-8 -*-
 """
-oauthlib.oauth2.rfc6749.grant_types
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+oauthlib.oauth2.rfc6749.request_validator
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 """
-from __future__ import unicode_literals, absolute_import
-
 import logging
 
 log = logging.getLogger(__name__)
 
 
-class RequestValidator(object):
+class RequestValidator:
 
     def client_authentication_required(self, request, *args, **kwargs):
         """Determine if client authentication is required for current request.
@@ -26,7 +23,8 @@ class RequestValidator(object):
               client credentials or whenever Client provided client authentication, see
               `Section 6`_
 
-        :param request: oauthlib.common.Request
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -34,9 +32,9 @@ class RequestValidator(object):
             - Resource Owner Password Credentials Grant
             - Refresh Token Grant
 
-        .. _`Section 4.3.2`: http://tools.ietf.org/html/rfc6749#section-4.3.2
-        .. _`Section 4.1.3`: http://tools.ietf.org/html/rfc6749#section-4.1.3
-        .. _`Section 6`: http://tools.ietf.org/html/rfc6749#section-6
+        .. _`Section 4.3.2`: https://tools.ietf.org/html/rfc6749#section-4.3.2
+        .. _`Section 4.1.3`: https://tools.ietf.org/html/rfc6749#section-4.1.3
+        .. _`Section 6`: https://tools.ietf.org/html/rfc6749#section-6
         """
         return True
 
@@ -50,8 +48,20 @@ class RequestValidator(object):
         Headers may be accesses through request.headers and parameters found in
         both body and query can be obtained by direct attribute access, i.e.
         request.client_id for client_id in the URL query.
+		
+        The authentication process is required to contain the identification of
+        the client (i.e. search the database based on the client_id). In case the
+        client doesn't exist based on the received client_id, this method has to
+        return False and the HTTP response created by the library will contain
+        'invalid_client' message. 
 
-        :param request: oauthlib.common.Request
+        After the client identification succeeds, this method needs to set the
+        client on the request, i.e. request.client = client. A client object's
+        class must contain the 'client_id' attribute and the 'client_id' must have
+        a value.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -60,7 +70,7 @@ class RequestValidator(object):
             - Client Credentials Grant
             - Refresh Token Grant
 
-        .. _`HTTP Basic Authentication Scheme`: http://tools.ietf.org/html/rfc1945#section-11.1
+        .. _`HTTP Basic Authentication Scheme`: https://tools.ietf.org/html/rfc1945#section-11.1
         """
         raise NotImplementedError('Subclasses must implement this method.')
 
@@ -74,7 +84,9 @@ class RequestValidator(object):
         to set request.client to the client object associated with the
         given client_id.
 
-        :param request: oauthlib.common.Request
+        :param client_id: Unicode client identifier.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -82,7 +94,7 @@ class RequestValidator(object):
         """
         raise NotImplementedError('Subclasses must implement this method.')
 
-    def confirm_redirect_uri(self, client_id, code, redirect_uri, client,
+    def confirm_redirect_uri(self, client_id, code, redirect_uri, client, request,
                              *args, **kwargs):
         """Ensure that the authorization process represented by this authorization
         code began with this 'redirect_uri'.
@@ -93,11 +105,12 @@ class RequestValidator(object):
         the client's allowed redirect URIs, but against the URI used when the
         code was saved.
 
-        :param client_id: Unicode client identifier
+        :param client_id: Unicode client identifier.
         :param code: Unicode authorization_code.
-        :param redirect_uri: Unicode absolute URI
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param redirect_uri: Unicode absolute URI.
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -108,8 +121,9 @@ class RequestValidator(object):
     def get_default_redirect_uri(self, client_id, request, *args, **kwargs):
         """Get the default redirect URI for the client.
 
-        :param client_id: Unicode client identifier
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param client_id: Unicode client identifier.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: The default redirect URI for the client
 
         Method is used by:
@@ -121,8 +135,9 @@ class RequestValidator(object):
     def get_default_scopes(self, client_id, request, *args, **kwargs):
         """Get the default scopes for the client.
 
-        :param client_id: Unicode client identifier
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param client_id: Unicode client identifier.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: List of default scopes
 
         Method is used by all core grant types:
@@ -136,8 +151,9 @@ class RequestValidator(object):
     def get_original_scopes(self, refresh_token, request, *args, **kwargs):
         """Get the list of scopes associated with the refresh token.
 
-        :param refresh_token: Unicode refresh token
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param refresh_token: Unicode refresh token.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: List of scopes.
 
         Method is used by:
@@ -156,9 +172,10 @@ class RequestValidator(object):
         used in situations where returning all valid scopes from the
         get_original_scopes is not practical.
 
-        :param request_scopes: A list of scopes that were requested by client
-        :param refresh_token: Unicode refresh_token
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param request_scopes: A list of scopes that were requested by client.
+        :param refresh_token: Unicode refresh_token.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -166,12 +183,54 @@ class RequestValidator(object):
         """
         return False
 
+    def introspect_token(self, token, token_type_hint, request, *args, **kwargs):
+        """Introspect an access or refresh token.
+
+        Called once the introspect request is validated. This method should
+        verify the *token* and either return a dictionary with the list of
+        claims associated, or `None` in case the token is unknown.
+
+        Below the list of registered claims you should be interested in:
+        - scope : space-separated list of scopes
+        - client_id : client identifier
+        - username : human-readable identifier for the resource owner
+        - token_type : type of the token
+        - exp : integer timestamp indicating when this token will expire
+        - iat : integer timestamp indicating when this token was issued
+        - nbf : integer timestamp indicating when it can be "not-before" used
+        - sub : subject of the token - identifier of the resource owner
+        - aud : list of string identifiers representing the intended audience
+        - iss : string representing issuer of this token
+        - jti : string identifier for the token
+
+        Note that most of them are coming directly from JWT RFC. More details
+        can be found in `Introspect Claims`_ or `_JWT Claims`_.
+
+        The implementation can use *token_type_hint* to improve lookup
+        efficency, but must fallback to other types to be compliant with RFC.
+
+        The dict of claims is added to request.token after this method.
+
+        :param token: The token string.
+        :param token_type_hint: access_token or refresh_token.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+
+        Method is used by:
+            - Introspect Endpoint (all grants are compatible)
+
+        .. _`Introspect Claims`: https://tools.ietf.org/html/rfc7662#section-2.2
+        .. _`JWT Claims`: https://tools.ietf.org/html/rfc7519#section-4
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
     def invalidate_authorization_code(self, client_id, code, request, *args, **kwargs):
         """Invalidate an authorization code after use.
 
-        :param client_id: Unicode client identifier
+        :param client_id: Unicode client identifier.
         :param code: The authorization code grant (request.code).
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         Method is used by:
             - Authorization Code Grant
@@ -183,7 +242,8 @@ class RequestValidator(object):
 
         :param token: The token string.
         :param token_type_hint: access_token or refresh_token.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         Method is used by:
             - Revocation Endpoint
@@ -197,7 +257,8 @@ class RequestValidator(object):
         or replaced with a new one (rotated). Return True to rotate and
         and False for keeping original.
 
-        :param request: oauthlib.common.Request
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -209,30 +270,49 @@ class RequestValidator(object):
         """Persist the authorization_code.
 
         The code should at minimum be stored with:
-            - the client_id (client_id)
-            - the redirect URI used (request.redirect_uri)
-            - a resource owner / user (request.user)
-            - the authorized scopes (request.scopes)
-            - the client state, if given (code.get('state'))
+            - the client_id (``client_id``)
+            - the redirect URI used (``request.redirect_uri``)
+            - a resource owner / user (``request.user``)
+            - the authorized scopes (``request.scopes``)
 
-        The 'code' argument is actually a dictionary, containing at least a
-        'code' key with the actual authorization code:
+        To support PKCE, you MUST associate the code with:
+            - Code Challenge (``request.code_challenge``) and
+            - Code Challenge Method (``request.code_challenge_method``)
 
-            {'code': 'sdf345jsdf0934f'}
+        To support OIDC, you MUST associate the code with:
+            - nonce, if present (``code["nonce"]``)
 
-        It may also have a 'state' key containing a nonce for the client, if it
-        chose to send one.  That value should be saved and used in
-        'validate_code'.
+        The ``code`` argument is actually a dictionary, containing at least a
+        ``code`` key with the actual authorization code:
 
-        :param client_id: Unicode client identifier
+            ``{'code': 'sdf345jsdf0934f'}``
+
+        It may also have a ``claims`` parameter which, when present, will be a dict
+        deserialized from JSON as described at
+        http://openid.net/specs/openid-connect-core-1_0.html#ClaimsParameter
+        This value should be saved in this method and used again in ``.validate_code``.
+
+        :param client_id: Unicode client identifier.
         :param code: A dict of the authorization code grant and, optionally, state.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         Method is used by:
             - Authorization Code Grant
         """
         raise NotImplementedError('Subclasses must implement this method.')
 
+    def save_token(self, token, request, *args, **kwargs):
+        """Persist the token with a token type specific method.
+
+        Currently, only save_bearer_token is supported.
+
+        :param token: A (Bearer) token dict.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
+        return self.save_bearer_token(token, request, *args, **kwargs)
+
     def save_bearer_token(self, token, request, *args, **kwargs):
         """Persist the Bearer token.
 
@@ -242,6 +322,7 @@ class RequestValidator(object):
             - authorized scopes (request.scopes)
             - an expiration time
             - a refresh token, if issued
+            - a claims document, if present in request.claims
 
         The Bearer token dict may hold a number of items::
 
@@ -251,15 +332,27 @@ class RequestValidator(object):
                 'expires_in': 3600,
                 'scope': 'string of space separated authorized scopes',
                 'refresh_token': '23sdf876234',  # if issued
-                'state': 'given_by_client',  # if supplied by client
+                'state': 'given_by_client',  # if supplied by client (implicit ONLY)
             }
 
         Note that while "scope" is a string-separated list of authorized scopes,
-        the original list is still available in request.scopes
+        the original list is still available in request.scopes.
 
-        :param client_id: Unicode client identifier
-        :param token: A Bearer token dict
-        :param request: The HTTP Request (oauthlib.common.Request)
+        The token dict is passed as a reference so any changes made to the dictionary
+        will go back to the user.  If additional information must return to the client
+        user, and it is only possible to get this information after writing the token
+        to storage, it should be added to the token dictionary.  If the token
+        dictionary must be modified but the changes should not go back to the user,
+        a copy of the dictionary must be made before making the changes.
+
+        Also note that if an Authorization Code grant request included a valid claims
+        parameter (for OpenID Connect) then the request.claims property will contain
+        the claims dict, which should be saved for later use when generating the
+        id_token and/or UserInfo response content.
+
+        :param token: A Bearer token dict.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: The default redirect URI for the client
 
         Method is used by all core grant types issuing Bearer tokens:
@@ -275,7 +368,8 @@ class RequestValidator(object):
 
         :param token: A string of random characters.
         :param scopes: A list of scopes associated with the protected resource.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
 
         A key to OAuth 2 security and restricting impact of leaked tokens is
         the short expiration time of tokens, *always ensure the token has not
@@ -309,7 +403,8 @@ class RequestValidator(object):
 
         :param token: Unicode Bearer token
         :param scopes: List of scopes (defined by you)
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is indirectly used by all core Bearer token issuing grant types:
@@ -327,7 +422,9 @@ class RequestValidator(object):
         to set request.client to the client object associated with the
         given client_id.
 
-        :param request: oauthlib.common.Request
+        :param client_id: Unicode client identifier.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -344,16 +441,24 @@ class RequestValidator(object):
         with the code in 'save_authorization_code':
 
             - request.user
-            - request.state (if given)
             - request.scopes
+            - request.claims (if given)
         OBS! The request.user attribute should be set to the resource owner
         associated with this authorization code. Similarly request.scopes
         must also be set.
 
-        :param client_id: Unicode client identifier
-        :param code: Unicode authorization code
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        The request.claims property, if it was given, should assigned a dict.
+
+        If PKCE is enabled (see 'is_pkce_required' and 'save_authorization_code')
+        you MUST set the following based on the information stored:
+            - request.code_challenge
+            - request.code_challenge_method
+
+        :param client_id: Unicode client identifier.
+        :param code: Unicode authorization code.
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -364,10 +469,11 @@ class RequestValidator(object):
     def validate_grant_type(self, client_id, grant_type, client, request, *args, **kwargs):
         """Ensure client is authorized to use the grant_type requested.
 
-        :param client_id: Unicode client identifier
+        :param client_id: Unicode client identifier.
         :param grant_type: Unicode grant type, i.e. authorization_code, password.
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -384,9 +490,10 @@ class RequestValidator(object):
         All clients should register the absolute URIs of all URIs they intend
         to redirect to. The registration is outside of the scope of oauthlib.
 
-        :param client_id: Unicode client identifier
-        :param redirect_uri: Unicode absolute URI
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param client_id: Unicode client identifier.
+        :param redirect_uri: Unicode absolute URI.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -401,9 +508,10 @@ class RequestValidator(object):
         OBS! The request.user attribute should be set to the resource owner
         associated with this refresh token.
 
-        :param refresh_token: Unicode refresh token
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param refresh_token: Unicode refresh token.
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -416,10 +524,11 @@ class RequestValidator(object):
     def validate_response_type(self, client_id, response_type, client, request, *args, **kwargs):
         """Ensure client is authorized to use the response_type requested.
 
-        :param client_id: Unicode client identifier
+        :param client_id: Unicode client identifier.
         :param response_type: Unicode response type, i.e. code, token.
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
@@ -431,10 +540,11 @@ class RequestValidator(object):
     def validate_scopes(self, client_id, scopes, client, request, *args, **kwargs):
         """Ensure the client is authorized access to requested scopes.
 
-        :param client_id: Unicode client identifier
-        :param scopes: List of scopes (defined by you)
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param client_id: Unicode client identifier.
+        :param scopes: List of scopes (defined by you).
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by all core grant types:
@@ -453,13 +563,89 @@ class RequestValidator(object):
         not set you will be unable to associate a token with a user in the
         persistance method used (commonly, save_bearer_token).
 
-        :param username: Unicode username
-        :param password: Unicode password
-        :param client: Client object set by you, see authenticate_client.
-        :param request: The HTTP Request (oauthlib.common.Request)
+        :param username: Unicode username.
+        :param password: Unicode password.
+        :param client: Client object set by you, see ``.authenticate_client``.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
         :rtype: True or False
 
         Method is used by:
             - Resource Owner Password Credentials Grant
         """
         raise NotImplementedError('Subclasses must implement this method.')
+
+    def is_pkce_required(self, client_id, request):
+        """Determine if current request requires PKCE. Default, False.
+        This is called for both "authorization" and "token" requests.
+
+        Override this method by ``return True`` to enable PKCE for everyone.
+        You might want to enable it only for public clients.
+        Note that PKCE can also be used in addition of a client authentication.
+
+        OAuth 2.0 public clients utilizing the Authorization Code Grant are
+        susceptible to the authorization code interception attack.  This
+        specification describes the attack as well as a technique to mitigate
+        against the threat through the use of Proof Key for Code Exchange
+        (PKCE, pronounced "pixy"). See `RFC7636`_.
+
+        :param client_id: Client identifier.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: True or False
+
+        Method is used by:
+            - Authorization Code Grant
+
+        .. _`RFC7636`: https://tools.ietf.org/html/rfc7636
+        """
+        return False
+
+    def get_code_challenge(self, code, request):
+        """Is called for every "token" requests.
+
+        When the server issues the authorization code in the authorization
+        response, it MUST associate the ``code_challenge`` and
+        ``code_challenge_method`` values with the authorization code so it can
+        be verified later.
+
+        Typically, the ``code_challenge`` and ``code_challenge_method`` values
+        are stored in encrypted form in the ``code`` itself but could
+        alternatively be stored on the server associated with the code.  The
+        server MUST NOT include the ``code_challenge`` value in client requests
+        in a form that other entities can extract.
+
+        Return the ``code_challenge`` associated to the code.
+        If ``None`` is returned, code is considered to not be associated to any
+        challenges.
+
+        :param code: Authorization code.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: code_challenge string
+
+        Method is used by:
+            - Authorization Code Grant - when PKCE is active
+
+        """
+        return None
+
+    def get_code_challenge_method(self, code, request):
+        """Is called during the "token" request processing, when a
+        ``code_verifier`` and a ``code_challenge`` has been provided.
+
+        See ``.get_code_challenge``.
+
+        Must return ``plain`` or ``S256``. You can return a custom value if you have
+        implemented your own ``AuthorizationCodeGrant`` class.
+
+        :param code: Authorization code.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: code_challenge_method string
+
+        Method is used by:
+            - Authorization Code Grant - when PKCE is active
+
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
diff --git a/lib/oauthlib/oauth2/rfc6749/tokens.py b/lib/oauthlib/oauth2/rfc6749/tokens.py
index 53f42ca6..6284248d 100644
--- a/lib/oauthlib/oauth2/rfc6749/tokens.py
+++ b/lib/oauthlib/oauth2/rfc6749/tokens.py
@@ -4,21 +4,17 @@ oauthlib.oauth2.rfc6749.tokens
 
 This module contains methods for adding two types of access tokens to requests.
 
-- Bearer http://tools.ietf.org/html/rfc6750
-- MAC http://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01
+- Bearer https://tools.ietf.org/html/rfc6750
+- MAC https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01
 """
-from __future__ import absolute_import, unicode_literals
-
-from binascii import b2a_base64
 import hashlib
 import hmac
-try:
-    from urlparse import urlparse
-except ImportError:
-    from urllib.parse import urlparse
+import warnings
+from binascii import b2a_base64
+from urllib.parse import urlparse
 
-from oauthlib.common import add_params_to_uri, add_params_to_qs, unicode_type
 from oauthlib import common
+from oauthlib.common import add_params_to_qs, add_params_to_uri
 
 from . import utils
 
@@ -26,7 +22,7 @@ from . import utils
 class OAuth2Token(dict):
 
     def __init__(self, params, old_scope=None):
-        super(OAuth2Token, self).__init__(params)
+        super().__init__(params)
         self._new_scope = None
         if 'scope' in params and params['scope']:
             self._new_scope = set(utils.scope_to_list(params['scope']))
@@ -92,13 +88,17 @@ def prepare_mac_header(token, uri, key, http_method,
                        nonce="1336363200:dj83hs9s",
                        mac="bhCQXTVyfj5cmA9uKkPFx1zeOXM="
 
-    .. _`MAC Access Authentication`: http://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01
-    .. _`extension algorithms`: http://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01#section-7.1
+    .. _`MAC Access Authentication`: https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01
+    .. _`extension algorithms`: https://tools.ietf.org/html/draft-ietf-oauth-v2-http-mac-01#section-7.1
 
+    :param token:
     :param uri: Request URI.
-    :param headers: Request headers as a dictionary.
-    :param http_method: HTTP Request method.
     :param key: MAC given provided by token endpoint.
+    :param http_method: HTTP Request method.
+    :param nonce:
+    :param headers: Request headers as a dictionary.
+    :param body:
+    :param ext:
     :param hash_algorithm: HMAC algorithm provided by token endpoint.
     :param issue_time: Time when the MAC credentials were issued (datetime).
     :param draft: MAC authentication specification version.
@@ -115,7 +115,7 @@ def prepare_mac_header(token, uri, key, http_method,
         raise ValueError('unknown hash algorithm')
 
     if draft == 0:
-        nonce = nonce or '{0}:{1}'.format(utils.generate_age(issue_time),
+        nonce = nonce or '{}:{}'.format(utils.generate_age(issue_time),
                                           common.generate_nonce())
     else:
         ts = common.generate_timestamp()
@@ -152,7 +152,7 @@ def prepare_mac_header(token, uri, key, http_method,
     base_string = '\n'.join(base) + '\n'
 
     # hmac struggles with unicode strings - http://bugs.python.org/issue5285
-    if isinstance(key, unicode_type):
+    if isinstance(key, str):
         key = key.encode('utf-8')
     sign = hmac.new(key, base_string.encode('utf-8'), h)
     sign = b2a_base64(sign.digest())[:-1].decode('utf-8')
@@ -179,7 +179,10 @@ def prepare_bearer_uri(token, uri):
 
     http://www.example.com/path?access_token=h480djs93hd8
 
-    .. _`Bearer Token`: http://tools.ietf.org/html/rfc6750
+    .. _`Bearer Token`: https://tools.ietf.org/html/rfc6750
+
+    :param token:
+    :param uri:
     """
     return add_params_to_uri(uri, [(('access_token', token))])
 
@@ -190,7 +193,10 @@ def prepare_bearer_headers(token, headers=None):
 
     Authorization: Bearer h480djs93hd8
 
-    .. _`Bearer Token`: http://tools.ietf.org/html/rfc6750
+    .. _`Bearer Token`: https://tools.ietf.org/html/rfc6750
+
+    :param token:
+    :param headers:
     """
     headers = headers or {}
     headers['Authorization'] = 'Bearer %s' % token
@@ -202,16 +208,27 @@ def prepare_bearer_body(token, body=''):
 
     access_token=h480djs93hd8
 
-    .. _`Bearer Token`: http://tools.ietf.org/html/rfc6750
+    .. _`Bearer Token`: https://tools.ietf.org/html/rfc6750
+
+    :param token:
+    :param body:
     """
     return add_params_to_qs(body, [(('access_token', token))])
 
 
 def random_token_generator(request, refresh_token=False):
+    """
+    :param request: OAuthlib request.
+    :type request: oauthlib.common.Request
+    :param refresh_token:
+    """
     return common.generate_token()
 
 
 def signed_token_generator(private_pem, **kwargs):
+    """
+    :param private_pem:
+    """
     def signed_token_generator(request):
         request.claims = kwargs
         return common.generate_signed_token(private_pem, request)
@@ -219,15 +236,43 @@ def signed_token_generator(private_pem, **kwargs):
     return signed_token_generator
 
 
-class TokenBase(object):
+def get_token_from_header(request):
+    """
+    Helper function to extract a token from the request header.
+
+    :param request: OAuthlib request.
+    :type request: oauthlib.common.Request
+    :return: Return the token or None if the Authorization header is malformed.
+    """
+    token = None
+
+    if 'Authorization' in request.headers:
+        split_header = request.headers.get('Authorization').split()
+        if len(split_header) == 2 and split_header[0].lower() == 'bearer':
+            token = split_header[1]
+    else:
+        token = request.access_token
+
+    return token
+
+
+class TokenBase:
 
     def __call__(self, request, refresh_token=False):
         raise NotImplementedError('Subclasses must implement this method.')
 
     def validate_request(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         raise NotImplementedError('Subclasses must implement this method.')
 
     def estimate_type(self, request):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
         raise NotImplementedError('Subclasses must implement this method.')
 
 
@@ -246,8 +291,18 @@ class BearerToken(TokenBase):
         )
         self.expires_in = expires_in or 3600
 
-    def create_token(self, request, refresh_token=False):
-        """Create a BearerToken, by default without refresh token."""
+    def create_token(self, request, refresh_token=False, **kwargs):
+        """
+        Create a BearerToken, by default without refresh token.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :param refresh_token:
+        """
+        if "save_token" in kwargs:
+            warnings.warn("`save_token` has been deprecated, it was not called internally."
+                          "If you do, call `request_validator.save_token()` instead.",
+                          DeprecationWarning)
 
         if callable(self.expires_in):
             expires_in = self.expires_in(request)
@@ -262,12 +317,12 @@ class BearerToken(TokenBase):
             'token_type': 'Bearer',
         }
 
+        # If provided, include - this is optional in some cases https://tools.ietf.org/html/rfc6749#section-3.3 but
+        # there is currently no mechanism to coordinate issuing a token for only a subset of the requested scopes so
+        # all tokens issued are for the entire set of requested scopes.
         if request.scopes is not None:
             token['scope'] = ' '.join(request.scopes)
 
-        if request.state is not None:
-            token['state'] = request.state
-
         if refresh_token:
             if (request.refresh_token and
                     not self.request_validator.rotate_refresh_token(request)):
@@ -276,21 +331,23 @@ class BearerToken(TokenBase):
                 token['refresh_token'] = self.refresh_token_generator(request)
 
         token.update(request.extra_credentials or {})
-        token = OAuth2Token(token)
-        self.request_validator.save_bearer_token(token, request)
-        return token
+        return OAuth2Token(token)
 
     def validate_request(self, request):
-        token = None
-        if 'Authorization' in request.headers:
-            token = request.headers.get('Authorization')[7:]
-        else:
-            token = request.access_token
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
+        token = get_token_from_header(request)
         return self.request_validator.validate_bearer_token(
             token, request.scopes, request)
 
     def estimate_type(self, request):
-        if request.headers.get('Authorization', '').startswith('Bearer'):
+        """
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        """
+        if request.headers.get('Authorization', '').split(' ')[0].lower() == 'bearer':
             return 9
         elif request.access_token is not None:
             return 5
diff --git a/lib/oauthlib/oauth2/rfc6749/utils.py b/lib/oauthlib/oauth2/rfc6749/utils.py
index 870ac325..7dc27b3d 100644
--- a/lib/oauthlib/oauth2/rfc6749/utils.py
+++ b/lib/oauthlib/oauth2/rfc6749/utils.py
@@ -1,31 +1,22 @@
-# -*- coding: utf-8 -*-
 """
 oauthlib.utils
 ~~~~~~~~~~~~~~
 
 This module contains utility methods used by various parts of the OAuth 2 spec.
 """
-from __future__ import absolute_import, unicode_literals
-
-import os
 import datetime
-try:
-    from urllib import quote
-except ImportError:
-    from urllib.parse import quote
-try:
-    from urlparse import urlparse
-except ImportError:
-    from urllib.parse import urlparse
-from oauthlib.common import unicode_type, urldecode
+import os
+from urllib.parse import quote, urlparse
+
+from oauthlib.common import urldecode
 
 
 def list_to_scope(scope):
     """Convert a list of scopes to a space separated string."""
-    if isinstance(scope, unicode_type) or scope is None:
+    if isinstance(scope, str) or scope is None:
         return scope
     elif isinstance(scope, (set, tuple, list)):
-        return " ".join([unicode_type(s) for s in scope])
+        return " ".join([str(s) for s in scope])
     else:
         raise ValueError("Invalid scope (%s), must be string, tuple, set, or list." % scope)
 
@@ -33,7 +24,7 @@ def list_to_scope(scope):
 def scope_to_list(scope):
     """Convert a space separated string to a list of scopes."""
     if isinstance(scope, (tuple, list, set)):
-        return [unicode_type(s) for s in scope]
+        return [str(s) for s in scope]
     elif scope is None:
         return None
     else:
@@ -72,7 +63,7 @@ def escape(u):
     TODO: verify whether this can in fact be used for OAuth 2
 
     """
-    if not isinstance(u, unicode_type):
+    if not isinstance(u, str):
         raise ValueError('Only unicode objects are escapable.')
     return quote(u.encode('utf-8'), safe=b'~')
 
@@ -82,7 +73,7 @@ def generate_age(issue_time):
     td = datetime.datetime.now() - issue_time
     age = (td.microseconds + (td.seconds + td.days * 24 * 3600)
            * 10 ** 6) / 10 ** 6
-    return unicode_type(age)
+    return str(age)
 
 
 def is_secure_transport(uri):
diff --git a/lib/oauthlib/openid/__init__.py b/lib/oauthlib/openid/__init__.py
new file mode 100644
index 00000000..e3174374
--- /dev/null
+++ b/lib/oauthlib/openid/__init__.py
@@ -0,0 +1,7 @@
+"""
+oauthlib.openid
+~~~~~~~~~~~~~~
+
+"""
+from .connect.core.endpoints import Server, UserInfoEndpoint
+from .connect.core.request_validator import RequestValidator
diff --git a/lib/oauthlib/openid/connect/__init__.py b/lib/oauthlib/openid/connect/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/lib/oauthlib/openid/connect/core/__init__.py b/lib/oauthlib/openid/connect/core/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/lib/oauthlib/openid/connect/core/endpoints/__init__.py b/lib/oauthlib/openid/connect/core/endpoints/__init__.py
new file mode 100644
index 00000000..7017ff4f
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/endpoints/__init__.py
@@ -0,0 +1,9 @@
+"""
+oauthlib.oopenid.core
+~~~~~~~~~~~~~~~~~~~~~~~
+
+This module is an implementation of various logic needed
+for consuming and providing OpenID Connect
+"""
+from .pre_configured import Server
+from .userinfo import UserInfoEndpoint
diff --git a/lib/oauthlib/openid/connect/core/endpoints/pre_configured.py b/lib/oauthlib/openid/connect/core/endpoints/pre_configured.py
new file mode 100644
index 00000000..8ce8bee6
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/endpoints/pre_configured.py
@@ -0,0 +1,97 @@
+"""
+oauthlib.openid.connect.core.endpoints.pre_configured
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This module is an implementation of various endpoints needed
+for providing OpenID Connect servers.
+"""
+from oauthlib.oauth2.rfc6749.endpoints import (
+    AuthorizationEndpoint, IntrospectEndpoint, ResourceEndpoint,
+    RevocationEndpoint, TokenEndpoint,
+)
+from oauthlib.oauth2.rfc6749.grant_types import (
+    AuthorizationCodeGrant as OAuth2AuthorizationCodeGrant,
+    ClientCredentialsGrant, ImplicitGrant as OAuth2ImplicitGrant,
+    RefreshTokenGrant, ResourceOwnerPasswordCredentialsGrant,
+)
+from oauthlib.oauth2.rfc6749.tokens import BearerToken
+
+from ..grant_types import AuthorizationCodeGrant, HybridGrant, ImplicitGrant
+from ..grant_types.dispatchers import (
+    AuthorizationCodeGrantDispatcher, AuthorizationTokenGrantDispatcher,
+    ImplicitTokenGrantDispatcher,
+)
+from ..tokens import JWTToken
+from .userinfo import UserInfoEndpoint
+
+
+class Server(AuthorizationEndpoint, IntrospectEndpoint, TokenEndpoint,
+             ResourceEndpoint, RevocationEndpoint, UserInfoEndpoint):
+
+    """An all-in-one endpoint featuring all four major grant types."""
+
+    def __init__(self, request_validator, token_expires_in=None,
+                 token_generator=None, refresh_token_generator=None,
+                 *args, **kwargs):
+        """Construct a new all-grants-in-one server.
+
+        :param request_validator: An implementation of
+                                  oauthlib.oauth2.RequestValidator.
+        :param token_expires_in: An int or a function to generate a token
+                                 expiration offset (in seconds) given a
+                                 oauthlib.common.Request object.
+        :param token_generator: A function to generate a token from a request.
+        :param refresh_token_generator: A function to generate a token from a
+                                        request for the refresh token.
+        :param kwargs: Extra parameters to pass to authorization-,
+                       token-, resource-, and revocation-endpoint constructors.
+        """
+        self.auth_grant = OAuth2AuthorizationCodeGrant(request_validator)
+        self.implicit_grant = OAuth2ImplicitGrant(request_validator)
+        self.password_grant = ResourceOwnerPasswordCredentialsGrant(
+            request_validator)
+        self.credentials_grant = ClientCredentialsGrant(request_validator)
+        self.refresh_grant = RefreshTokenGrant(request_validator)
+        self.openid_connect_auth = AuthorizationCodeGrant(request_validator)
+        self.openid_connect_implicit = ImplicitGrant(request_validator)
+        self.openid_connect_hybrid = HybridGrant(request_validator)
+
+        self.bearer = BearerToken(request_validator, token_generator,
+                             token_expires_in, refresh_token_generator)
+
+        self.jwt = JWTToken(request_validator, token_generator,
+                       token_expires_in, refresh_token_generator)
+
+        self.auth_grant_choice = AuthorizationCodeGrantDispatcher(default_grant=self.auth_grant, oidc_grant=self.openid_connect_auth)
+        self.implicit_grant_choice = ImplicitTokenGrantDispatcher(default_grant=self.implicit_grant, oidc_grant=self.openid_connect_implicit)
+
+        # See http://openid.net/specs/oauth-v2-multiple-response-types-1_0.html#Combinations for valid combinations
+        # internally our AuthorizationEndpoint will ensure they can appear in any order for any valid combination
+        AuthorizationEndpoint.__init__(self, default_response_type='code',
+                                       response_types={
+                                           'code': self.auth_grant_choice,
+                                           'token': self.implicit_grant_choice,
+                                           'id_token': self.openid_connect_implicit,
+                                           'id_token token': self.openid_connect_implicit,
+                                           'code token': self.openid_connect_hybrid,
+                                           'code id_token': self.openid_connect_hybrid,
+                                           'code id_token token': self.openid_connect_hybrid,
+                                           'none': self.auth_grant
+                                       },
+                                       default_token_type=self.bearer)
+
+        self.token_grant_choice = AuthorizationTokenGrantDispatcher(request_validator, default_grant=self.auth_grant, oidc_grant=self.openid_connect_auth)
+
+        TokenEndpoint.__init__(self, default_grant_type='authorization_code',
+                               grant_types={
+                                   'authorization_code': self.token_grant_choice,
+                                   'password': self.password_grant,
+                                   'client_credentials': self.credentials_grant,
+                                   'refresh_token': self.refresh_grant,
+                               },
+                               default_token_type=self.bearer)
+        ResourceEndpoint.__init__(self, default_token='Bearer',
+                                  token_types={'Bearer': self.bearer, 'JWT': self.jwt})
+        RevocationEndpoint.__init__(self, request_validator)
+        IntrospectEndpoint.__init__(self, request_validator)
+        UserInfoEndpoint.__init__(self, request_validator)
diff --git a/lib/oauthlib/openid/connect/core/endpoints/userinfo.py b/lib/oauthlib/openid/connect/core/endpoints/userinfo.py
new file mode 100644
index 00000000..1c29cc55
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/endpoints/userinfo.py
@@ -0,0 +1,99 @@
+"""
+oauthlib.openid.connect.core.endpoints.userinfo
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This module is an implementation of userinfo endpoint.
+"""
+import json
+import logging
+
+from oauthlib.common import Request
+from oauthlib.oauth2.rfc6749 import errors
+from oauthlib.oauth2.rfc6749.endpoints.base import (
+    BaseEndpoint, catch_errors_and_unavailability,
+)
+from oauthlib.oauth2.rfc6749.tokens import BearerToken
+
+log = logging.getLogger(__name__)
+
+
+class UserInfoEndpoint(BaseEndpoint):
+    """Authorizes access to userinfo resource.
+    """
+    def __init__(self, request_validator):
+        self.bearer = BearerToken(request_validator, None, None, None)
+        self.request_validator = request_validator
+        BaseEndpoint.__init__(self)
+
+    @catch_errors_and_unavailability
+    def create_userinfo_response(self, uri, http_method='GET', body=None, headers=None):
+        """Validate BearerToken and return userinfo from RequestValidator
+
+        The UserInfo Endpoint MUST return a
+        content-type header to indicate which format is being returned. The
+        content-type of the HTTP response MUST be application/json if the
+        response body is a text JSON object; the response body SHOULD be encoded
+        using UTF-8.
+        """
+        request = Request(uri, http_method, body, headers)
+        request.scopes = ["openid"]
+        self.validate_userinfo_request(request)
+
+        claims = self.request_validator.get_userinfo_claims(request)
+        if claims is None:
+            log.error('Userinfo MUST have claims for %r.', request)
+            raise errors.ServerError(status_code=500)
+
+        if isinstance(claims, dict):
+            resp_headers = {
+                'Content-Type': 'application/json'
+            }
+            if "sub" not in claims:
+                log.error('Userinfo MUST have "sub" for %r.', request)
+                raise errors.ServerError(status_code=500)
+            body = json.dumps(claims)
+        elif isinstance(claims, str):
+            resp_headers = {
+                'Content-Type': 'application/jwt'
+            }
+            body = claims
+        else:
+            log.error('Userinfo return unknown response for %r.', request)
+            raise errors.ServerError(status_code=500)
+        log.debug('Userinfo access valid for %r.', request)
+        return resp_headers, body, 200
+
+    def validate_userinfo_request(self, request):
+        """Ensure the request is valid.
+
+        5.3.1.  UserInfo Request
+        The Client sends the UserInfo Request using either HTTP GET or HTTP
+        POST. The Access Token obtained from an OpenID Connect Authentication
+        Request MUST be sent as a Bearer Token, per Section 2 of OAuth 2.0
+        Bearer Token Usage [RFC6750].
+
+        It is RECOMMENDED that the request use the HTTP GET method and the
+        Access Token be sent using the Authorization header field.
+
+        The following is a non-normative example of a UserInfo Request:
+
+        GET /userinfo HTTP/1.1
+        Host: server.example.com
+        Authorization: Bearer SlAV32hkKG
+
+        5.3.3. UserInfo Error Response
+        When an error condition occurs, the UserInfo Endpoint returns an Error
+        Response as defined in Section 3 of OAuth 2.0 Bearer Token Usage
+        [RFC6750]. (HTTP errors unrelated to RFC 6750 are returned to the User
+        Agent using the appropriate HTTP status code.)
+
+        The following is a non-normative example of a UserInfo Error Response:
+
+        HTTP/1.1 401 Unauthorized
+        WWW-Authenticate: Bearer error="invalid_token",
+                error_description="The Access Token expired"
+        """
+        if not self.bearer.validate_request(request):
+            raise errors.InvalidTokenError()
+        if "openid" not in request.scopes:
+            raise errors.InsufficientScopeError()
diff --git a/lib/oauthlib/openid/connect/core/exceptions.py b/lib/oauthlib/openid/connect/core/exceptions.py
new file mode 100644
index 00000000..099b84e2
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/exceptions.py
@@ -0,0 +1,149 @@
+"""
+oauthlib.oauth2.rfc6749.errors
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Error used both by OAuth 2 clients and providers to represent the spec
+defined error responses for all four core grant types.
+"""
+from oauthlib.oauth2.rfc6749.errors import FatalClientError, OAuth2Error
+
+
+class FatalOpenIDClientError(FatalClientError):
+    pass
+
+
+class OpenIDClientError(OAuth2Error):
+    pass
+
+
+class InteractionRequired(OpenIDClientError):
+    """
+    The Authorization Server requires End-User interaction to proceed.
+
+    This error MAY be returned when the prompt parameter value in the
+    Authentication Request is none, but the Authentication Request cannot be
+    completed without displaying a user interface for End-User interaction.
+    """
+    error = 'interaction_required'
+    status_code = 401
+
+
+class LoginRequired(OpenIDClientError):
+    """
+    The Authorization Server requires End-User authentication.
+
+    This error MAY be returned when the prompt parameter value in the
+    Authentication Request is none, but the Authentication Request cannot be
+    completed without displaying a user interface for End-User authentication.
+    """
+    error = 'login_required'
+    status_code = 401
+
+
+class AccountSelectionRequired(OpenIDClientError):
+    """
+    The End-User is REQUIRED to select a session at the Authorization Server.
+
+    The End-User MAY be authenticated at the Authorization Server with
+    different associated accounts, but the End-User did not select a session.
+    This error MAY be returned when the prompt parameter value in the
+    Authentication Request is none, but the Authentication Request cannot be
+    completed without displaying a user interface to prompt for a session to
+    use.
+    """
+    error = 'account_selection_required'
+
+
+class ConsentRequired(OpenIDClientError):
+    """
+    The Authorization Server requires End-User consent.
+
+    This error MAY be returned when the prompt parameter value in the
+    Authentication Request is none, but the Authentication Request cannot be
+    completed without displaying a user interface for End-User consent.
+    """
+    error = 'consent_required'
+    status_code = 401
+
+
+class InvalidRequestURI(OpenIDClientError):
+    """
+    The request_uri in the Authorization Request returns an error or
+    contains invalid data.
+    """
+    error = 'invalid_request_uri'
+    description = 'The request_uri in the Authorization Request returns an ' \
+                  'error or contains invalid data.'
+
+
+class InvalidRequestObject(OpenIDClientError):
+    """
+    The request parameter contains an invalid Request Object.
+    """
+    error = 'invalid_request_object'
+    description = 'The request parameter contains an invalid Request Object.'
+
+
+class RequestNotSupported(OpenIDClientError):
+    """
+    The OP does not support use of the request parameter.
+    """
+    error = 'request_not_supported'
+    description = 'The request parameter is not supported.'
+
+
+class RequestURINotSupported(OpenIDClientError):
+    """
+    The OP does not support use of the request_uri parameter.
+    """
+    error = 'request_uri_not_supported'
+    description = 'The request_uri parameter is not supported.'
+
+
+class RegistrationNotSupported(OpenIDClientError):
+    """
+    The OP does not support use of the registration parameter.
+    """
+    error = 'registration_not_supported'
+    description = 'The registration parameter is not supported.'
+
+
+class InvalidTokenError(OAuth2Error):
+    """
+    The access token provided is expired, revoked, malformed, or
+    invalid for other reasons.  The resource SHOULD respond with
+    the HTTP 401 (Unauthorized) status code.  The client MAY
+    request a new access token and retry the protected resource
+    request.
+    """
+    error = 'invalid_token'
+    status_code = 401
+    description = ("The access token provided is expired, revoked, malformed, "
+                   "or invalid for other reasons.")
+
+
+class InsufficientScopeError(OAuth2Error):
+    """
+    The request requires higher privileges than provided by the
+    access token.  The resource server SHOULD respond with the HTTP
+    403 (Forbidden) status code and MAY include the "scope"
+    attribute with the scope necessary to access the protected
+    resource.
+    """
+    error = 'insufficient_scope'
+    status_code = 403
+    description = ("The request requires higher privileges than provided by "
+                   "the access token.")
+
+
+def raise_from_error(error, params=None):
+    import inspect
+    import sys
+    kwargs = {
+        'description': params.get('error_description'),
+        'uri': params.get('error_uri'),
+        'state': params.get('state')
+    }
+    for _, cls in inspect.getmembers(sys.modules[__name__], inspect.isclass):
+        if cls.error == error:
+            raise cls(**kwargs)
diff --git a/lib/oauthlib/openid/connect/core/grant_types/__init__.py b/lib/oauthlib/openid/connect/core/grant_types/__init__.py
new file mode 100644
index 00000000..887a5850
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/grant_types/__init__.py
@@ -0,0 +1,12 @@
+"""
+oauthlib.openid.connect.core.grant_types
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+"""
+from .authorization_code import AuthorizationCodeGrant
+from .base import GrantTypeBase
+from .dispatchers import (
+    AuthorizationCodeGrantDispatcher, AuthorizationTokenGrantDispatcher,
+    ImplicitTokenGrantDispatcher,
+)
+from .hybrid import HybridGrant
+from .implicit import ImplicitGrant
diff --git a/lib/oauthlib/openid/connect/core/grant_types/authorization_code.py b/lib/oauthlib/openid/connect/core/grant_types/authorization_code.py
new file mode 100644
index 00000000..6b2dcc3b
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/grant_types/authorization_code.py
@@ -0,0 +1,43 @@
+"""
+oauthlib.openid.connect.core.grant_types
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+"""
+import logging
+
+from oauthlib.oauth2.rfc6749.grant_types.authorization_code import (
+    AuthorizationCodeGrant as OAuth2AuthorizationCodeGrant,
+)
+
+from .base import GrantTypeBase
+
+log = logging.getLogger(__name__)
+
+
+class AuthorizationCodeGrant(GrantTypeBase):
+
+    def __init__(self, request_validator=None, **kwargs):
+        self.proxy_target = OAuth2AuthorizationCodeGrant(
+            request_validator=request_validator, **kwargs)
+        self.custom_validators.post_auth.append(
+            self.openid_authorization_validator)
+        self.register_token_modifier(self.add_id_token)
+
+    def add_id_token(self, token, token_handler, request):
+        """
+        Construct an initial version of id_token, and let the
+        request_validator sign or encrypt it.
+
+        The authorization_code version of this method is used to
+        retrieve the nonce accordingly to the code storage.
+        """
+        # Treat it as normal OAuth 2 auth code request if openid is not present
+        if not request.scopes or 'openid' not in request.scopes:
+            return token
+
+        nonce = self.request_validator.get_authorization_code_nonce(
+            request.client_id,
+            request.code,
+            request.redirect_uri,
+            request
+        )
+        return super().add_id_token(token, token_handler, request, nonce=nonce)
diff --git a/lib/oauthlib/openid/connect/core/grant_types/base.py b/lib/oauthlib/openid/connect/core/grant_types/base.py
new file mode 100644
index 00000000..76173e6c
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/grant_types/base.py
@@ -0,0 +1,327 @@
+import base64
+import hashlib
+import logging
+import time
+from json import loads
+
+from oauthlib.oauth2.rfc6749.errors import (
+    ConsentRequired, InvalidRequestError, LoginRequired,
+)
+
+
+log = logging.getLogger(__name__)
+
+
+class GrantTypeBase:
+
+    # Just proxy the majority of method calls through to the
+    # proxy_target grant type handler, which will usually be either
+    # the standard OAuth2 AuthCode or Implicit grant types.
+    def __getattr__(self, attr):
+        return getattr(self.proxy_target, attr)
+
+    def __setattr__(self, attr, value):
+        proxied_attrs = {'refresh_token', 'response_types'}
+        if attr in proxied_attrs:
+            setattr(self.proxy_target, attr, value)
+        else:
+            super(OpenIDConnectBase, self).__setattr__(attr, value)
+
+    def validate_authorization_request(self, request):
+        """Validates the OpenID Connect authorization request parameters.
+
+        :returns: (list of scopes, dict of request info)
+        """
+        return self.proxy_target.validate_authorization_request(request)
+
+    def _inflate_claims(self, request):
+        # this may be called multiple times in a single request so make sure we only de-serialize the claims once
+        if request.claims and not isinstance(request.claims, dict):
+            # specific claims are requested during the Authorization Request and may be requested for inclusion
+            # in either the id_token or the UserInfo endpoint response
+            # see http://openid.net/specs/openid-connect-core-1_0.html#ClaimsParameter
+            try:
+                request.claims = loads(request.claims)
+            except Exception as ex:
+                raise InvalidRequestError(description="Malformed claims parameter",
+                                          uri="http://openid.net/specs/openid-connect-core-1_0.html#ClaimsParameter")
+
+    def id_token_hash(self, value, hashfunc=hashlib.sha256):
+        """
+        Its value is the base64url encoding of the left-most half of the
+        hash of the octets of the ASCII representation of the access_token
+        value, where the hash algorithm used is the hash algorithm used in
+        the alg Header Parameter of the ID Token's JOSE Header.
+
+        For instance, if the alg is RS256, hash the access_token value
+        with SHA-256, then take the left-most 128 bits and
+        base64url-encode them.
+        For instance, if the alg is HS512, hash the code value with
+        SHA-512, then take the left-most 256 bits and base64url-encode
+        them. The c_hash value is a case-sensitive string.
+
+        Example of hash from OIDC specification (bound to a JWS using RS256):
+
+        code:
+        Qcb0Orv1zh30vL1MPRsbm-diHiMwcLyZvn1arpZv-Jxf_11jnpEX3Tgfvk
+
+        c_hash:
+        LDktKdoQak3Pk0cnXxCltA
+        """
+        digest = hashfunc(value.encode()).digest()
+        left_most = len(digest) // 2
+        return base64.urlsafe_b64encode(digest[:left_most]).decode().rstrip("=")
+
+    def add_id_token(self, token, token_handler, request, nonce=None):
+        """
+        Construct an initial version of id_token, and let the
+        request_validator sign or encrypt it.
+
+        The initial version can contain the fields below, accordingly
+        to the spec:
+        - aud
+        - iat
+        - nonce
+        - at_hash
+        - c_hash
+        """
+        # Treat it as normal OAuth 2 auth code request if openid is not present
+        if not request.scopes or 'openid' not in request.scopes:
+            return token
+
+        # Only add an id token on auth/token step if asked for.
+        if request.response_type and 'id_token' not in request.response_type:
+            return token
+
+        # Implementation mint its own id_token without help.
+        id_token = self.request_validator.get_id_token(token, token_handler, request)
+        if id_token:
+            token['id_token'] = id_token
+            return token
+
+        # Fallback for asking some help from oauthlib framework.
+        # Start with technicals fields bound to the specification.
+        id_token = {}
+        id_token['aud'] = request.client_id
+        id_token['iat'] = int(time.time())
+
+        # nonce is REQUIRED when response_type value is:
+        # - id_token token (Implicit)
+        # - id_token (Implicit)
+        # - code id_token (Hybrid)
+        # - code id_token token (Hybrid)
+        #
+        # nonce is OPTIONAL when response_type value is:
+        # - code (Authorization Code)
+        # - code token (Hybrid)
+        if nonce is not None:
+            id_token["nonce"] = nonce
+
+        # at_hash is REQUIRED when response_type value is:
+        # - id_token token (Implicit)
+        # - code id_token token (Hybrid)
+        #
+        # at_hash is OPTIONAL when:
+        # - code (Authorization code)
+        # - code id_token (Hybrid)
+        # - code token (Hybrid)
+        #
+        # at_hash MAY NOT be used when:
+        # - id_token (Implicit)
+        if "access_token" in token:
+            id_token["at_hash"] = self.id_token_hash(token["access_token"])
+
+        # c_hash is REQUIRED when response_type value is:
+        # - code id_token (Hybrid)
+        # - code id_token token (Hybrid)
+        #
+        # c_hash is OPTIONAL for others.
+        if "code" in token:
+            id_token["c_hash"] = self.id_token_hash(token["code"])
+
+        # Call request_validator to complete/sign/encrypt id_token
+        token['id_token'] = self.request_validator.finalize_id_token(id_token, token, token_handler, request)
+
+        return token
+
+    def openid_authorization_validator(self, request):
+        """Perform OpenID Connect specific authorization request validation.
+
+        nonce
+                OPTIONAL. String value used to associate a Client session with
+                an ID Token, and to mitigate replay attacks. The value is
+                passed through unmodified from the Authentication Request to
+                the ID Token. Sufficient entropy MUST be present in the nonce
+                values used to prevent attackers from guessing values
+
+        display
+                OPTIONAL. ASCII string value that specifies how the
+                Authorization Server displays the authentication and consent
+                user interface pages to the End-User. The defined values are:
+
+                    page - The Authorization Server SHOULD display the
+                    authentication and consent UI consistent with a full User
+                    Agent page view. If the display parameter is not specified,
+                    this is the default display mode.
+
+                    popup - The Authorization Server SHOULD display the
+                    authentication and consent UI consistent with a popup User
+                    Agent window. The popup User Agent window should be of an
+                    appropriate size for a login-focused dialog and should not
+                    obscure the entire window that it is popping up over.
+
+                    touch - The Authorization Server SHOULD display the
+                    authentication and consent UI consistent with a device that
+                    leverages a touch interface.
+
+                    wap - The Authorization Server SHOULD display the
+                    authentication and consent UI consistent with a "feature
+                    phone" type display.
+
+                The Authorization Server MAY also attempt to detect the
+                capabilities of the User Agent and present an appropriate
+                display.
+
+        prompt
+                OPTIONAL. Space delimited, case sensitive list of ASCII string
+                values that specifies whether the Authorization Server prompts
+                the End-User for reauthentication and consent. The defined
+                values are:
+
+                    none - The Authorization Server MUST NOT display any
+                    authentication or consent user interface pages. An error is
+                    returned if an End-User is not already authenticated or the
+                    Client does not have pre-configured consent for the
+                    requested Claims or does not fulfill other conditions for
+                    processing the request. The error code will typically be
+                    login_required, interaction_required, or another code
+                    defined in Section 3.1.2.6. This can be used as a method to
+                    check for existing authentication and/or consent.
+
+                    login - The Authorization Server SHOULD prompt the End-User
+                    for reauthentication. If it cannot reauthenticate the
+                    End-User, it MUST return an error, typically
+                    login_required.
+
+                    consent - The Authorization Server SHOULD prompt the
+                    End-User for consent before returning information to the
+                    Client. If it cannot obtain consent, it MUST return an
+                    error, typically consent_required.
+
+                    select_account - The Authorization Server SHOULD prompt the
+                    End-User to select a user account. This enables an End-User
+                    who has multiple accounts at the Authorization Server to
+                    select amongst the multiple accounts that they might have
+                    current sessions for. If it cannot obtain an account
+                    selection choice made by the End-User, it MUST return an
+                    error, typically account_selection_required.
+
+                The prompt parameter can be used by the Client to make sure
+                that the End-User is still present for the current session or
+                to bring attention to the request. If this parameter contains
+                none with any other value, an error is returned.
+
+        max_age
+                OPTIONAL. Maximum Authentication Age. Specifies the allowable
+                elapsed time in seconds since the last time the End-User was
+                actively authenticated by the OP. If the elapsed time is
+                greater than this value, the OP MUST attempt to actively
+                re-authenticate the End-User. (The max_age request parameter
+                corresponds to the OpenID 2.0 PAPE [OpenID.PAPE] max_auth_age
+                request parameter.) When max_age is used, the ID Token returned
+                MUST include an auth_time Claim Value.
+
+        ui_locales
+                OPTIONAL. End-User's preferred languages and scripts for the
+                user interface, represented as a space-separated list of BCP47
+                [RFC5646] language tag values, ordered by preference. For
+                instance, the value "fr-CA fr en" represents a preference for
+                French as spoken in Canada, then French (without a region
+                designation), followed by English (without a region
+                designation). An error SHOULD NOT result if some or all of the
+                requested locales are not supported by the OpenID Provider.
+
+        id_token_hint
+                OPTIONAL. ID Token previously issued by the Authorization
+                Server being passed as a hint about the End-User's current or
+                past authenticated session with the Client. If the End-User
+                identified by the ID Token is logged in or is logged in by the
+                request, then the Authorization Server returns a positive
+                response; otherwise, it SHOULD return an error, such as
+                login_required. When possible, an id_token_hint SHOULD be
+                present when prompt=none is used and an invalid_request error
+                MAY be returned if it is not; however, the server SHOULD
+                respond successfully when possible, even if it is not present.
+                The Authorization Server need not be listed as an audience of
+                the ID Token when it is used as an id_token_hint value. If the
+                ID Token received by the RP from the OP is encrypted, to use it
+                as an id_token_hint, the Client MUST decrypt the signed ID
+                Token contained within the encrypted ID Token. The Client MAY
+                re-encrypt the signed ID token to the Authentication Server
+                using a key that enables the server to decrypt the ID Token,
+                and use the re-encrypted ID token as the id_token_hint value.
+
+        login_hint
+                OPTIONAL. Hint to the Authorization Server about the login
+                identifier the End-User might use to log in (if necessary).
+                This hint can be used by an RP if it first asks the End-User
+                for their e-mail address (or other identifier) and then wants
+                to pass that value as a hint to the discovered authorization
+                service. It is RECOMMENDED that the hint value match the value
+                used for discovery. This value MAY also be a phone number in
+                the format specified for the phone_number Claim. The use of
+                this parameter is left to the OP's discretion.
+
+        acr_values
+                OPTIONAL. Requested Authentication Context Class Reference
+                values. Space-separated string that specifies the acr values
+                that the Authorization Server is being requested to use for
+                processing this Authentication Request, with the values
+                appearing in order of preference. The Authentication Context
+                Class satisfied by the authentication performed is returned as
+                the acr Claim Value, as specified in Section 2. The acr Claim
+                is requested as a Voluntary Claim by this parameter.
+        """
+
+        # Treat it as normal OAuth 2 auth code request if openid is not present
+        if not request.scopes or 'openid' not in request.scopes:
+            return {}
+
+        prompt = request.prompt if request.prompt else []
+        if hasattr(prompt, 'split'):
+            prompt = prompt.strip().split()
+        prompt = set(prompt)
+
+        if 'none' in prompt:
+
+            if len(prompt) > 1:
+                msg = "Prompt none is mutually exclusive with other values."
+                raise InvalidRequestError(request=request, description=msg)
+
+            if not self.request_validator.validate_silent_login(request):
+                raise LoginRequired(request=request)
+
+            if not self.request_validator.validate_silent_authorization(request):
+                raise ConsentRequired(request=request)
+
+        self._inflate_claims(request)
+
+        if not self.request_validator.validate_user_match(
+                request.id_token_hint, request.scopes, request.claims, request):
+            msg = "Session user does not match client supplied user."
+            raise LoginRequired(request=request, description=msg)
+
+        request_info = {
+            'display': request.display,
+            'nonce': request.nonce,
+            'prompt': prompt,
+            'ui_locales': request.ui_locales.split() if request.ui_locales else [],
+            'id_token_hint': request.id_token_hint,
+            'login_hint': request.login_hint,
+            'claims': request.claims
+        }
+
+        return request_info
+
+
+OpenIDConnectBase = GrantTypeBase
diff --git a/lib/oauthlib/openid/connect/core/grant_types/dispatchers.py b/lib/oauthlib/openid/connect/core/grant_types/dispatchers.py
new file mode 100644
index 00000000..2734c387
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/grant_types/dispatchers.py
@@ -0,0 +1,101 @@
+import logging
+
+log = logging.getLogger(__name__)
+
+
+class Dispatcher:
+    default_grant = None
+    oidc_grant = None
+
+
+class AuthorizationCodeGrantDispatcher(Dispatcher):
+    """
+    This is an adapter class that will route simple Authorization Code
+    requests, those that have `response_type=code` and a scope including
+    `openid` to either the `default_grant` or the `oidc_grant` based on
+    the scopes requested.
+    """
+    def __init__(self, default_grant=None, oidc_grant=None):
+        self.default_grant = default_grant
+        self.oidc_grant = oidc_grant
+
+    def _handler_for_request(self, request):
+        handler = self.default_grant
+
+        if request.scopes and "openid" in request.scopes:
+            handler = self.oidc_grant
+
+        log.debug('Selecting handler for request %r.', handler)
+        return handler
+
+    def create_authorization_response(self, request, token_handler):
+        """Read scope and route to the designated handler."""
+        return self._handler_for_request(request).create_authorization_response(request, token_handler)
+
+    def validate_authorization_request(self, request):
+        """Read scope and route to the designated handler."""
+        return self._handler_for_request(request).validate_authorization_request(request)
+
+
+class ImplicitTokenGrantDispatcher(Dispatcher):
+    """
+    This is an adapter class that will route simple Authorization
+    requests, those that have `id_token` in `response_type` and a scope
+    including `openid` to either the `default_grant` or the `oidc_grant`
+    based on the scopes requested.
+    """
+    def __init__(self, default_grant=None, oidc_grant=None):
+        self.default_grant = default_grant
+        self.oidc_grant = oidc_grant
+
+    def _handler_for_request(self, request):
+        handler = self.default_grant
+
+        if request.scopes and "openid" in request.scopes and 'id_token' in request.response_type:
+            handler = self.oidc_grant
+
+        log.debug('Selecting handler for request %r.', handler)
+        return handler
+
+    def create_authorization_response(self, request, token_handler):
+        """Read scope and route to the designated handler."""
+        return self._handler_for_request(request).create_authorization_response(request, token_handler)
+
+    def validate_authorization_request(self, request):
+        """Read scope and route to the designated handler."""
+        return self._handler_for_request(request).validate_authorization_request(request)
+
+
+class AuthorizationTokenGrantDispatcher(Dispatcher):
+    """
+    This is an adapter class that will route simple Token requests, those that authorization_code have a scope
+    including 'openid' to either the default_grant or the oidc_grant based on the scopes requested.
+    """
+    def __init__(self, request_validator, default_grant=None, oidc_grant=None):
+        self.default_grant = default_grant
+        self.oidc_grant = oidc_grant
+        self.request_validator = request_validator
+
+    def _handler_for_request(self, request):
+        handler = self.default_grant
+        scopes = ()
+        parameters = dict(request.decoded_body)
+        client_id = parameters.get('client_id', None)
+        code = parameters.get('code', None)
+        redirect_uri = parameters.get('redirect_uri', None)
+
+        # If code is not pressent fallback to `default_grant` which will
+        # raise an error for the missing `code` in `create_token_response` step.
+        if code:
+            scopes = self.request_validator.get_authorization_code_scopes(client_id, code, redirect_uri, request)
+
+        if 'openid' in scopes:
+            handler = self.oidc_grant
+
+        log.debug('Selecting handler for request %r.', handler)
+        return handler
+
+    def create_token_response(self, request, token_handler):
+        """Read scope and route to the designated handler."""
+        handler = self._handler_for_request(request)
+        return handler.create_token_response(request, token_handler)
diff --git a/lib/oauthlib/openid/connect/core/grant_types/hybrid.py b/lib/oauthlib/openid/connect/core/grant_types/hybrid.py
new file mode 100644
index 00000000..7cb0758b
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/grant_types/hybrid.py
@@ -0,0 +1,63 @@
+"""
+oauthlib.openid.connect.core.grant_types
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+"""
+import logging
+
+from oauthlib.oauth2.rfc6749.errors import InvalidRequestError
+from oauthlib.oauth2.rfc6749.grant_types.authorization_code import (
+    AuthorizationCodeGrant as OAuth2AuthorizationCodeGrant,
+)
+
+from ..request_validator import RequestValidator
+from .base import GrantTypeBase
+
+log = logging.getLogger(__name__)
+
+
+class HybridGrant(GrantTypeBase):
+
+    def __init__(self, request_validator=None, **kwargs):
+        self.request_validator = request_validator or RequestValidator()
+
+        self.proxy_target = OAuth2AuthorizationCodeGrant(
+            request_validator=request_validator, **kwargs)
+        # All hybrid response types should be fragment-encoded.
+        self.proxy_target.default_response_mode = "fragment"
+        self.register_response_type('code id_token')
+        self.register_response_type('code token')
+        self.register_response_type('code id_token token')
+        self.custom_validators.post_auth.append(
+            self.openid_authorization_validator)
+        # Hybrid flows can return the id_token from the authorization
+        # endpoint as part of the 'code' response
+        self.register_code_modifier(self.add_token)
+        self.register_code_modifier(self.add_id_token)
+        self.register_token_modifier(self.add_id_token)
+
+    def add_id_token(self, token, token_handler, request):
+        return super().add_id_token(token, token_handler, request, nonce=request.nonce)
+
+    def openid_authorization_validator(self, request):
+        """Additional validation when following the Authorization Code flow.
+        """
+        request_info = super().openid_authorization_validator(request)
+        if not request_info:  # returns immediately if OAuth2.0
+            return request_info
+
+        # REQUIRED if the Response Type of the request is `code
+        # id_token` or `code id_token token` and OPTIONAL when the
+        # Response Type of the request is `code token`. It is a string
+        # value used to associate a Client session with an ID Token,
+        # and to mitigate replay attacks. The value is passed through
+        # unmodified from the Authentication Request to the ID
+        # Token. Sufficient entropy MUST be present in the `nonce`
+        # values used to prevent attackers from guessing values. For
+        # implementation notes, see Section 15.5.2.
+        if request.response_type in ["code id_token", "code id_token token"]:
+            if not request.nonce:
+                raise InvalidRequestError(
+                    request=request,
+                    description='Request is missing mandatory nonce parameter.'
+                )
+        return request_info
diff --git a/lib/oauthlib/openid/connect/core/grant_types/implicit.py b/lib/oauthlib/openid/connect/core/grant_types/implicit.py
new file mode 100644
index 00000000..a4fe6049
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/grant_types/implicit.py
@@ -0,0 +1,51 @@
+"""
+oauthlib.openid.connect.core.grant_types
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+"""
+import logging
+
+from oauthlib.oauth2.rfc6749.errors import InvalidRequestError
+from oauthlib.oauth2.rfc6749.grant_types.implicit import (
+    ImplicitGrant as OAuth2ImplicitGrant,
+)
+
+from .base import GrantTypeBase
+
+log = logging.getLogger(__name__)
+
+
+class ImplicitGrant(GrantTypeBase):
+
+    def __init__(self, request_validator=None, **kwargs):
+        self.proxy_target = OAuth2ImplicitGrant(
+            request_validator=request_validator, **kwargs)
+        self.register_response_type('id_token')
+        self.register_response_type('id_token token')
+        self.custom_validators.post_auth.append(
+            self.openid_authorization_validator)
+        self.register_token_modifier(self.add_id_token)
+
+    def add_id_token(self, token, token_handler, request):
+        if 'state' not in token and request.state:
+            token['state'] = request.state
+        return super().add_id_token(token, token_handler, request, nonce=request.nonce)
+
+    def openid_authorization_validator(self, request):
+        """Additional validation when following the implicit flow.
+        """
+        request_info = super().openid_authorization_validator(request)
+        if not request_info:  # returns immediately if OAuth2.0
+            return request_info
+
+        # REQUIRED. String value used to associate a Client session with an ID
+        # Token, and to mitigate replay attacks. The value is passed through
+        # unmodified from the Authentication Request to the ID Token.
+        # Sufficient entropy MUST be present in the nonce values used to
+        # prevent attackers from guessing values. For implementation notes, see
+        # Section 15.5.2.
+        if not request.nonce:
+            raise InvalidRequestError(
+                request=request,
+                description='Request is missing mandatory nonce parameter.'
+            )
+        return request_info
diff --git a/lib/oauthlib/openid/connect/core/request_validator.py b/lib/oauthlib/openid/connect/core/request_validator.py
new file mode 100644
index 00000000..e8f334b0
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/request_validator.py
@@ -0,0 +1,308 @@
+"""
+oauthlib.openid.connect.core.request_validator
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+"""
+import logging
+
+from oauthlib.oauth2.rfc6749.request_validator import (
+    RequestValidator as OAuth2RequestValidator,
+)
+
+log = logging.getLogger(__name__)
+
+
+class RequestValidator(OAuth2RequestValidator):
+
+    def get_authorization_code_scopes(self, client_id, code, redirect_uri, request):
+        """ Extracts scopes from saved authorization code.
+
+        The scopes returned by this method is used to route token requests
+        based on scopes passed to Authorization Code requests.
+
+        With that the token endpoint knows when to include OpenIDConnect
+        id_token in token response only based on authorization code scopes.
+
+        Only code param should be sufficient to retrieve grant code from
+        any storage you are using, `client_id` and `redirect_uri` can have a
+        blank value `""` don't forget to check it before using those values
+        in a select query if a database is used.
+
+        :param client_id: Unicode client identifier
+        :param code: Unicode authorization code grant
+        :param redirect_uri: Unicode absolute URI
+        :return: A list of scope
+
+        Method is used by:
+            - Authorization Token Grant Dispatcher
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def get_authorization_code_nonce(self, client_id, code, redirect_uri, request):
+        """ Extracts nonce from saved authorization code.
+
+        If present in the Authentication Request, Authorization
+        Servers MUST include a nonce Claim in the ID Token with the
+        Claim Value being the nonce value sent in the Authentication
+        Request. Authorization Servers SHOULD perform no other
+        processing on nonce values used. The nonce value is a
+        case-sensitive string.
+
+        Only code param should be sufficient to retrieve grant code from
+        any storage you are using. However, `client_id` and `redirect_uri`
+        have been validated and can be used also.
+
+        :param client_id: Unicode client identifier
+        :param code: Unicode authorization code grant
+        :param redirect_uri: Unicode absolute URI
+        :return: Unicode nonce
+
+        Method is used by:
+            - Authorization Token Grant Dispatcher
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def get_jwt_bearer_token(self, token, token_handler, request):
+        """Get JWT Bearer token or OpenID Connect ID token
+
+        If using OpenID Connect this SHOULD call `oauthlib.oauth2.RequestValidator.get_id_token`
+
+        :param token: A Bearer token dict
+        :param token_handler: the token handler (BearerToken class)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :return: The JWT Bearer token or OpenID Connect ID token (a JWS signed JWT)
+
+        Method is used by JWT Bearer and OpenID Connect tokens:
+            - JWTToken.create_token
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def get_id_token(self, token, token_handler, request):
+        """Get OpenID Connect ID token
+
+        This method is OPTIONAL and is NOT RECOMMENDED.
+        `finalize_id_token` SHOULD be implemented instead. However, if you
+        want a full control over the minting of the `id_token`, you
+        MAY want to override `get_id_token` instead of using
+        `finalize_id_token`.
+
+        In the OpenID Connect workflows when an ID Token is requested this method is called.
+        Subclasses should implement the construction, signing and optional encryption of the
+        ID Token as described in the OpenID Connect spec.
+
+        In addition to the standard OAuth2 request properties, the request may also contain
+        these OIDC specific properties which are useful to this method:
+
+            - nonce, if workflow is implicit or hybrid and it was provided
+            - claims, if provided to the original Authorization Code request
+
+        The token parameter is a dict which may contain an ``access_token`` entry, in which
+        case the resulting ID Token *should* include a calculated ``at_hash`` claim.
+
+        Similarly, when the request parameter has a ``code`` property defined, the ID Token
+        *should* include a calculated ``c_hash`` claim.
+
+        http://openid.net/specs/openid-connect-core-1_0.html (sections `3.1.3.6`_, `3.2.2.10`_, `3.3.2.11`_)
+
+        .. _`3.1.3.6`: http://openid.net/specs/openid-connect-core-1_0.html#CodeIDToken
+        .. _`3.2.2.10`: http://openid.net/specs/openid-connect-core-1_0.html#ImplicitIDToken
+        .. _`3.3.2.11`: http://openid.net/specs/openid-connect-core-1_0.html#HybridIDToken
+
+        :param token: A Bearer token dict
+        :param token_handler: the token handler (BearerToken class)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :return: The ID Token (a JWS signed JWT)
+        """
+        return None
+
+    def finalize_id_token(self, id_token, token, token_handler, request):
+        """Finalize OpenID Connect ID token & Sign or Encrypt.
+
+        In the OpenID Connect workflows when an ID Token is requested
+        this method is called.  Subclasses should implement the
+        construction, signing and optional encryption of the ID Token
+        as described in the OpenID Connect spec.
+
+        The `id_token` parameter is a dict containing a couple of OIDC
+        technical fields related to the specification. Prepopulated
+        attributes are:
+
+        - `aud`, equals to `request.client_id`.
+        - `iat`, equals to current time.
+        - `nonce`, if present, is equals to the `nonce` from the
+          authorization request.
+        - `at_hash`, hash of `access_token`, if relevant.
+        - `c_hash`, hash of `code`, if relevant.
+
+        This method MUST provide required fields as below:
+
+        - `iss`, REQUIRED. Issuer Identifier for the Issuer of the response.
+        - `sub`, REQUIRED. Subject Identifier
+        - `exp`, REQUIRED. Expiration time on or after which the ID
+          Token MUST NOT be accepted by the RP when performing
+          authentication with the OP.
+
+        Additionals claims must be added, note that `request.scope`
+        should be used to determine the list of claims.
+
+        More information can be found at `OpenID Connect Core#Claims`_
+
+        .. _`OpenID Connect Core#Claims`: https://openid.net/specs/openid-connect-core-1_0.html#Claims
+
+        :param id_token: A dict containing technical fields of id_token
+        :param token: A Bearer token dict
+        :param token_handler: the token handler (BearerToken class)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :return: The ID Token (a JWS signed JWT or JWE encrypted JWT)
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def validate_jwt_bearer_token(self, token, scopes, request):
+        """Ensure the JWT Bearer token or OpenID Connect ID token are valids and authorized access to scopes.
+
+        If using OpenID Connect this SHOULD call `oauthlib.oauth2.RequestValidator.get_id_token`
+
+        If not using OpenID Connect this can `return None` to avoid 5xx rather 401/3 response.
+
+        OpenID connect core 1.0 describe how to validate an id_token:
+            - http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
+            - http://openid.net/specs/openid-connect-core-1_0.html#ImplicitIDTValidation
+            - http://openid.net/specs/openid-connect-core-1_0.html#HybridIDTValidation
+            - http://openid.net/specs/openid-connect-core-1_0.html#HybridIDTValidation2
+
+        :param token: Unicode Bearer token
+        :param scopes: List of scopes (defined by you)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: True or False
+
+        Method is indirectly used by all core OpenID connect JWT token issuing grant types:
+            - Authorization Code Grant
+            - Implicit Grant
+            - Hybrid Grant
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def validate_id_token(self, token, scopes, request):
+        """Ensure the id token is valid and authorized access to scopes.
+
+        OpenID connect core 1.0 describe how to validate an id_token:
+            - http://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation
+            - http://openid.net/specs/openid-connect-core-1_0.html#ImplicitIDTValidation
+            - http://openid.net/specs/openid-connect-core-1_0.html#HybridIDTValidation
+            - http://openid.net/specs/openid-connect-core-1_0.html#HybridIDTValidation2
+
+        :param token: Unicode Bearer token
+        :param scopes: List of scopes (defined by you)
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: True or False
+
+        Method is indirectly used by all core OpenID connect JWT token issuing grant types:
+            - Authorization Code Grant
+            - Implicit Grant
+            - Hybrid Grant
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def validate_silent_authorization(self, request):
+        """Ensure the logged in user has authorized silent OpenID authorization.
+
+        Silent OpenID authorization allows access tokens and id tokens to be
+        granted to clients without any user prompt or interaction.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: True or False
+
+        Method is used by:
+            - OpenIDConnectAuthCode
+            - OpenIDConnectImplicit
+            - OpenIDConnectHybrid
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def validate_silent_login(self, request):
+        """Ensure session user has authorized silent OpenID login.
+
+        If no user is logged in or has not authorized silent login, this
+        method should return False.
+
+        If the user is logged in but associated with multiple accounts and
+        not selected which one to link to the token then this method should
+        raise an oauthlib.oauth2.AccountSelectionRequired error.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: True or False
+
+        Method is used by:
+            - OpenIDConnectAuthCode
+            - OpenIDConnectImplicit
+            - OpenIDConnectHybrid
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def validate_user_match(self, id_token_hint, scopes, claims, request):
+        """Ensure client supplied user id hint matches session user.
+
+        If the sub claim or id_token_hint is supplied then the session
+        user must match the given ID.
+
+        :param id_token_hint: User identifier string.
+        :param scopes: List of OAuth 2 scopes and OpenID claims (strings).
+        :param claims: OpenID Connect claims dict.
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: True or False
+
+        Method is used by:
+            - OpenIDConnectAuthCode
+            - OpenIDConnectImplicit
+            - OpenIDConnectHybrid
+        """
+        raise NotImplementedError('Subclasses must implement this method.')
+
+    def get_userinfo_claims(self, request):
+        """Return the UserInfo claims in JSON or Signed or Encrypted.
+
+        The UserInfo Claims MUST be returned as the members of a JSON object
+         unless a signed or encrypted response was requested during Client
+         Registration. The Claims defined in Section 5.1 can be returned, as can
+         additional Claims not specified there.
+
+        For privacy reasons, OpenID Providers MAY elect to not return values for
+        some requested Claims.
+
+        If a Claim is not returned, that Claim Name SHOULD be omitted from the
+        JSON object representing the Claims; it SHOULD NOT be present with a
+        null or empty string value.
+
+        The sub (subject) Claim MUST always be returned in the UserInfo
+        Response.
+
+        Upon receipt of the UserInfo Request, the UserInfo Endpoint MUST return
+        the JSON Serialization of the UserInfo Response as in Section 13.3 in
+        the HTTP response body unless a different format was specified during
+        Registration [OpenID.Registration].
+
+        If the UserInfo Response is signed and/or encrypted, then the Claims are
+        returned in a JWT and the content-type MUST be application/jwt. The
+        response MAY be encrypted without also being signed. If both signing and
+        encryption are requested, the response MUST be signed then encrypted,
+        with the result being a Nested JWT, as defined in [JWT].
+
+        If signed, the UserInfo Response SHOULD contain the Claims iss (issuer)
+        and aud (audience) as members. The iss value SHOULD be the OP's Issuer
+        Identifier URL. The aud value SHOULD be or include the RP's Client ID
+        value.
+
+        :param request: OAuthlib request.
+        :type request: oauthlib.common.Request
+        :rtype: Claims as a dict OR JWT/JWS/JWE as a string
+
+        Method is used by:
+            UserInfoEndpoint
+        """
diff --git a/lib/oauthlib/openid/connect/core/tokens.py b/lib/oauthlib/openid/connect/core/tokens.py
new file mode 100644
index 00000000..a312e2d2
--- /dev/null
+++ b/lib/oauthlib/openid/connect/core/tokens.py
@@ -0,0 +1,46 @@
+"""
+authlib.openid.connect.core.tokens
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This module contains methods for adding JWT tokens to requests.
+"""
+from oauthlib.oauth2.rfc6749.tokens import TokenBase, random_token_generator, get_token_from_header
+
+
+class JWTToken(TokenBase):
+    __slots__ = (
+        'request_validator', 'token_generator',
+        'refresh_token_generator', 'expires_in'
+    )
+
+    def __init__(self, request_validator=None, token_generator=None,
+                 expires_in=None, refresh_token_generator=None):
+        self.request_validator = request_validator
+        self.token_generator = token_generator or random_token_generator
+        self.refresh_token_generator = (
+            refresh_token_generator or self.token_generator
+        )
+        self.expires_in = expires_in or 3600
+
+    def create_token(self, request, refresh_token=False):
+        """Create a JWT Token, using requestvalidator method."""
+
+        if callable(self.expires_in):
+            expires_in = self.expires_in(request)
+        else:
+            expires_in = self.expires_in
+
+        request.expires_in = expires_in
+
+        return self.request_validator.get_jwt_bearer_token(None, None, request)
+
+    def validate_request(self, request):
+        token = get_token_from_header(request)
+        return self.request_validator.validate_jwt_bearer_token(
+            token, request.scopes, request)
+
+    def estimate_type(self, request):
+        token = get_token_from_header(request)
+        if token and token.startswith('ey') and token.count('.') in (2, 4):
+            return 10
+        return 0
diff --git a/lib/oauthlib/signals.py b/lib/oauthlib/signals.py
index 2f866505..8fd347a5 100644
--- a/lib/oauthlib/signals.py
+++ b/lib/oauthlib/signals.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 """
     Implements signals based on blinker if available, otherwise
     falls silently back to a noop. Shamelessly stolen from flask.signals:
@@ -8,12 +7,12 @@ signals_available = False
 try:
     from blinker import Namespace
     signals_available = True
-except ImportError:
-    class Namespace(object):
+except ImportError:  # noqa
+    class Namespace:
         def signal(self, name, doc=None):
             return _FakeSignal(name, doc)
 
-    class _FakeSignal(object):
+    class _FakeSignal:
         """If blinker is unavailable, create a fake class with the same
         interface that allows sending of signals but will fail with an
         error on anything else.  Instead of doing anything on send, it
diff --git a/lib/oauthlib/uri_validate.py b/lib/oauthlib/uri_validate.py
index e553f32b..8a6d9c27 100644
--- a/lib/oauthlib/uri_validate.py
+++ b/lib/oauthlib/uri_validate.py
@@ -8,7 +8,6 @@ They should be processed with re.VERBOSE.
 
 Thanks Mark Nottingham for this code - https://gist.github.com/138549
 """
-from __future__ import unicode_literals
 import re
 
 # basics
@@ -66,32 +65,8 @@ dec_octet = r"""(?: %(DIGIT)s |
 IPv4address = r"%(dec_octet)s \. %(dec_octet)s \. %(dec_octet)s \. %(dec_octet)s" % locals(
 )
 
-#  h16           = 1*4HEXDIG
-h16 = r"(?: %(HEXDIG)s ){1,4}" % locals()
-
-#  ls32          = ( h16 ":" h16 ) / IPv4address
-ls32 = r"(?: (?: %(h16)s : %(h16)s ) | %(IPv4address)s )" % locals()
-
-#   IPv6address   =                            6( h16 ":" ) ls32
-#                 /                       "::" 5( h16 ":" ) ls32
-#                 / [               h16 ] "::" 4( h16 ":" ) ls32
-#                 / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
-#                 / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
-#                 / [ *3( h16 ":" ) h16 ] "::"    h16 ":"   ls32
-#                 / [ *4( h16 ":" ) h16 ] "::"              ls32
-#                 / [ *5( h16 ":" ) h16 ] "::"              h16
-#                 / [ *6( h16 ":" ) h16 ] "::"
-IPv6address = r"""(?:                                  (?: %(h16)s : ){6} %(ls32)s |
-                                                    :: (?: %(h16)s : ){5} %(ls32)s |
-                                            %(h16)s :: (?: %(h16)s : ){4} %(ls32)s |
-                         (?: %(h16)s : )    %(h16)s :: (?: %(h16)s : ){3} %(ls32)s |
-                         (?: %(h16)s : ){2} %(h16)s :: (?: %(h16)s : ){2} %(ls32)s |
-                         (?: %(h16)s : ){3} %(h16)s ::     %(h16)s :      %(ls32)s |
-                         (?: %(h16)s : ){4} %(h16)s ::                    %(ls32)s |
-                         (?: %(h16)s : ){5} %(h16)s ::                    %(h16)s  |
-                         (?: %(h16)s : ){6} %(h16)s ::
-                  )
-""" % locals()
+#   IPv6address
+IPv6address = r"([A-Fa-f0-9:]+:+)+[A-Fa-f0-9]+"
 
 #   IPvFuture     = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" )
 IPvFuture = r"v %(HEXDIG)s+ \. (?: %(unreserved)s | %(sub_delims)s | : )+" % locals()