From 5067a03c88896f818e1cc8e096e19384f1bc421b Mon Sep 17 00:00:00 2001
From: Evan Purkhiser <epurkhiser@crunchyroll.com>
Date: Fri, 9 Jan 2015 23:54:34 -0800
Subject: [PATCH] Use the etag in the internal AssetCache cache key

The etag provides slightly more metadata about the asset due to the way
the etag is constructed than the AssetCache does. This passes the etag
along to the AssetCache as a HashableInterface AssetFilter, where the
etag is considered the hash of the filter.
---
 Controller/AssetCacheKeyFilter.php | 50 ++++++++++++++++++++++++++++++
 Controller/AsseticController.php   |  4 ++-
 2 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 Controller/AssetCacheKeyFilter.php

diff --git a/Controller/AssetCacheKeyFilter.php b/Controller/AssetCacheKeyFilter.php
new file mode 100644
index 00000000..0ad13144
--- /dev/null
+++ b/Controller/AssetCacheKeyFilter.php
@@ -0,0 +1,50 @@
+<?php
+
+/*
+ * This file is part of the Assetic package, an OpenSky project.
+ *
+ * (c) 2010-2014 OpenSky Project Inc
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bundle\AsseticBundle\Controller;
+
+use Assetic\Asset\AssetInterface;
+use Assetic\Filter\FilterInterface;
+use Assetic\Filter\HashableInterface;
+
+/**
+ * This is a special filter that has a noop on its load and dump methods, but
+ * implements the HashableInterface, allowing it to be used with the AssetCache
+ * to include an additional cache key component.
+ */
+class AssetCacheKeyFilter implements HashableInterface, FilterInterface
+{
+    private $cacheKey;
+
+    /**
+     * @param string $cacheKey A string to use as a cache key component
+     */
+    public function __construct($cacheKey)
+    {
+        $this->cacheKey = $cacheKey;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function hash()
+    {
+        return $this->cacheKey;
+    }
+
+    public function filterLoad(AssetInterface $asset)
+    {
+    }
+
+    public function filterDump(AssetInterface $asset)
+    {
+    }
+}
diff --git a/Controller/AsseticController.php b/Controller/AsseticController.php
index c467ad9c..61d33342 100644
--- a/Controller/AsseticController.php
+++ b/Controller/AsseticController.php
@@ -86,7 +86,9 @@ public function render($name, $pos = null)
             return $response;
         }
 
-        $response->setContent($this->cachifyAsset($asset)->dump());
+        $etagCacheKeyFilter = new AssetCacheKeyFilter($response->getEtag());
+
+        $response->setContent($this->cachifyAsset($asset)->dump($etagCacheKeyFilter));
 
         return $response;
     }