spaces.php

aws/Aws/Signature/SignatureTrait.php

@@ -0,0 +1,49 @@
+<?php
+namespace Aws\Signature;
+
+/**
+ * Provides signature calculation for SignatureV4.
+ */
+trait SignatureTrait
+{
+    /** @var array Cache of previously signed values */
+    private $cache = [];
+
+    /** @var int Size of the hash cache */
+    private $cacheSize = 0;
+
+    private function createScope($shortDate, $region, $service)
+    {
+        return "$shortDate/$region/$service/aws4_request";
+    }
+
+    private function getSigningKey($shortDate, $region, $service, $secretKey)
+    {
+        $k = $shortDate . '_' . $region . '_' . $service . '_' . $secretKey;
+
+        if (!isset($this->cache[$k])) {
+            // Clear the cache when it reaches 50 entries
+            if (++$this->cacheSize > 50) {
+                $this->cache = [];
+                $this->cacheSize = 0;
+            }
+
+            $dateKey = hash_hmac(
+                'sha256',
+                $shortDate,
+                "AWS4{$secretKey}",
+                true
+            );
+            $regionKey = hash_hmac('sha256', $region, $dateKey, true);
+            $serviceKey = hash_hmac('sha256', $service, $regionKey, true);
+            $this->cache[$k] = hash_hmac(
+                'sha256',
+                'aws4_request',
+                $serviceKey,
+                true
+            );
+        }
+
+        return $this->cache[$k];
+    }
+}