Added node modules

node_modules/connect/lib/middleware/staticCache.js

@@ -0,0 +1,175 @@
+
+/*!
+ * Connect - staticCache
+ * Copyright(c) 2011 Sencha Inc.
+ * MIT Licensed
+ */
+
+/**
+ * Module dependencies.
+ */
+
+var http = require('http')
+  , utils = require('../utils')
+  , Cache = require('../cache')
+  , url = require('url')
+  , fs = require('fs');
+
+/**
+ * Enables a memory cache layer on top of
+ * the `static()` middleware, serving popular
+ * static files.
+ *
+ * By default a maximum of 128 objects are
+ * held in cache, with a max of 256k each,
+ * totalling ~32mb.
+ *
+ * A Least-Recently-Used (LRU) cache algo
+ * is implemented through the `Cache` object,
+ * simply rotating cache objects as they are
+ * hit. This means that increasingly popular
+ * objects maintain their positions while
+ * others get shoved out of the stack and
+ * garbage collected.
+ *
+ * Benchmarks:
+ *
+ *     static(): 2700 rps
+ *     node-static: 5300 rps
+ *     static() + staticCache(): 7500 rps
+ *
+ * Options:
+ *
+ *   - `maxObjects`  max cache objects [128]
+ *   - `maxLength`  max cache object length 256kb
+ *
+ * @param {Type} name
+ * @return {Type}
+ * @api public
+ */
+
+module.exports = function staticCache(options){
+  var options = options || {}
+    , cache = new Cache(options.maxObjects || 128)
+    , maxlen = options.maxLength || 1024 * 256;
+
+  return function staticCache(req, res, next){
+    var path = url.parse(req.url).pathname
+      , ranges = req.headers.range
+      , hit = cache.get(path)
+      , hitCC
+      , uaCC
+      , header
+      , age;
+
+    // cache static
+    req.on('static', function(stream){
+      var headers = res._headers
+        , cc = utils.parseCacheControl(headers['cache-control'] || '')
+        , contentLength = headers['content-length']
+        , hit;
+
+      // ignore larger files
+      if (!contentLength || contentLength > maxlen) return;
+
+      // dont cache items we shouldn't be
+      if ( cc['no-cache']
+        || cc['no-store']
+        || cc['private']
+        || cc['must-revalidate']) return;
+
+      // if already in cache then validate
+      if (hit = cache.get(path)){
+        if (headers.etag == hit[0].etag) {
+          hit[0].date = new Date;
+          return;
+        } else {
+          cache.remove(path);
+        }
+      }
+
+      // validation notifiactions don't contain a steam
+      if (null == stream) return;
+
+      // add the cache object
+      var arr = cache.add(path);
+      arr.push(headers);
+
+      // store the chunks
+      stream.on('data', function(chunk){
+        arr.push(chunk);
+      });
+
+      // flag it as complete
+      stream.on('end', function(){
+        arr.complete = true;
+      });
+    });
+
+    // cache hit, doesnt support range requests
+    if (hit && hit.complete && !ranges) {
+      header = utils.merge({}, hit[0]);
+      header.Age = age = (new Date - new Date(header.date)) / 1000 | 0;
+      header.date = new Date().toUTCString();
+
+      // parse cache-controls
+      hitCC = utils.parseCacheControl(header['cache-control'] || '');
+      uaCC = utils.parseCacheControl(req.headers['cache-control'] || '');
+
+      // check if we must revalidate(bypass)
+      if (hitCC['no-cache'] || uaCC['no-cache']) return next();
+
+      // check freshness of entity
+      if (isStale(hitCC, age) || isStale(uaCC, age)) return next();
+
+      // conditional GET support
+      if (utils.conditionalGET(req)) {
+        if (!utils.modified(req, res, header)) {
+          header['content-length'] = 0;
+          res.writeHead(304, header);
+          return res.end();
+        }
+      }
+
+      // HEAD support
+      if ('HEAD' == req.method) {
+        header['content-length'] = 0;
+        res.writeHead(200, header);
+        return res.end();
+      }
+
+      // respond with cache
+      res.writeHead(200, header);
+
+      // backpressure
+      function write(i) {
+        var buf = hit[i];
+        if (!buf) return res.end();
+        if (false === res.write(buf)) {
+          res.once('drain', function(){
+            write(++i);
+          });
+        } else {
+          write(++i);
+        }
+      }
+
+      return write(1);
+    }
+
+    next();
+  }
+};
+
+/**
+ * Check if cache item is stale
+ *
+ * @param {Object} cc
+ * @param {Number} age
+ * @return {Boolean}
+ * @api private
+ */
+
+function isStale(cc, age) {
+  return cc['max-age'] && cc['max-age'] <= age;
+}