Merge pull request #101 from KnpLabs/feature/etag

use ETag to decrease rate limit hits

Author: cursedcoder

lib/Github/HttpClient/Cache/CacheInterface.php

@@ -11,13 +11,27 @@
  */
 interface CacheInterface
 {
+    /**
+     * @param string $id The id of the cached resource
+     *
+     * @return bool if present
+     */
+    public function has($id);
+
     /**
      * @param string $id The id of the cached resource
      *
      * @return null|integer The modified since timestamp
      */
     public function getModifiedSince($id);
 
+    /**
+     * @param string $id The id of the cached resource
+     *
+     * @return null|string The ETag value
+     */
+    public function getETag($id);
+
     /**
      * @param string $id The id of the cached resource
      *

lib/Github/HttpClient/Cache/FilesystemCache.php

@@ -43,18 +43,34 @@ public function set($id, Response $response)
         if (false === @file_put_contents($this->getPath($id), serialize($response))) {
             throw new \InvalidArgumentException(sprintf('Cannot put content in file "%s"', $this->getPath($id)));
         }
+        if (false === @file_put_contents($this->getPath($id).'.etag', $response->getHeader('ETag'))) {
+            throw new \InvalidArgumentException(sprintf('Cannot put content in file "%s"', $this->getPath($id).'.etag'));
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function has($id)
+    {
+        return file_exists($this->getPath($id));
     }
 
     /**
      * {@inheritdoc}
      */
     public function getModifiedSince($id)
     {
-        if (file_exists($this->getPath($id))) {
+        if ($this->has($id)) {
             return filemtime($this->getPath($id));
         }
+    }
 
-        return null;
+    public function getETag($id)
+    {
+        if (file_exists($this->getPath($id).'.etag')) {
+            return file_get_contents($this->getPath($id).'.etag');
+        }
     }
 
     /**

lib/Github/HttpClient/Cache/GaufretteCache.php

@@ -41,6 +41,15 @@ public function get($id)
     public function set($id, Response $response)
     {
         $this->filesystem->write($id, serialize($response), true);
+        $this->filesystem->write($id.'.etag', $response->getHeader('ETag'), true);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function has($id)
+    {
+        $this->filesystem->has($id);
     }
 
     /**
@@ -52,4 +61,11 @@ public function getModifiedSince($id)
             return $this->filesystem->mtime($id);
         }
     }
+
+    public function getETag($id)
+    {
+        if ($this->filesystem->has($id)) {
+            return $this->filesystem->read($id.'.etag');
+        }
+    }
 }

lib/Github/HttpClient/CachedHttpClient.php

@@ -46,12 +46,11 @@ public function request($path, $body = null, $httpMethod = 'GET', array $headers
     {
         $response = parent::request($path, $body, $httpMethod, $headers, $options);
 
-        $key = trim($this->options['base_url'].$path, '/');
         if (304 == $response->getStatusCode()) {
-            return $this->getCache()->get($key);
+            return $this->getCache()->get($path);
         }
 
-        $this->getCache()->set($key, $response);
+        $this->getCache()->set($path, $response);
 
         return $response;
     }
@@ -74,6 +73,12 @@ protected function createRequest($httpMethod, $path, $body = null, array $header
                 sprintf('%s GMT', $modifiedAt->format('l, d-M-y H:i:s'))
             );
         }
+        if ($etag = $this->getCache()->getETag($path)) {
+            $request->addHeader(
+                'If-None-Match',
+                $etag
+            );
+        }
 
         return $request;
     }