Issue 43 - Added a cache clearer for generated images

Imagine/Cache/CacheClearer.php

@@ -0,0 +1,46 @@
+<?php
+
+namespace Liip\ImagineBundle\Imagine\Cache;
+
+use Symfony\Component\HttpKernel\CacheClearer\CacheClearerInterface;
+
+/**
+ * Clears the Liip Imagine Bundle cache
+ * 
+ * @author Josiah <josiah@web-dev.com.au>
+ */
+class CacheClearer implements CacheClearerInterface
+{
+    /**
+     * The Cache Manager
+     * 
+     * @var CacheManager
+     */
+    private $cacheManager;
+
+    /**
+     * The prefix applied to all cached images
+     * 
+     * @var string
+     */
+    private $cachePrefix;
+
+    /**
+     * @param CacheManager $cacheManager
+     */
+    public function __construct(CacheManager $cacheManager, $cachePrefix)
+    {
+        $this->cacheManager = $cacheManager;
+        $this->cachePrefix = $cachePrefix;
+    }
+
+    /**
+     * (non-PHPdoc)
+     * @see Symfony\Component\HttpKernel\CacheClearer\CacheClearerInterface::clear()
+     */
+    public function clear($cacheDir)
+    {
+        // $cacheDir contains the application cache, which we don't care about
+        $this->cacheManager->clearResolversCache($this->cachePrefix);
+    }
+}

Imagine/Cache/CacheManager.php

@@ -172,4 +172,11 @@ public function remove($targetPath, $filter)
     {
         return $this->getResolver($filter)->remove($targetPath, $filter);
     }
+
+    public function clearResolversCache($cachePrefix)
+    {
+        foreach ($this->resolvers as $resolver) {
+            $resolver->clear($cachePrefix);
+        }
+    }
 }

Imagine/Cache/Resolver/AmazonS3Resolver.php

@@ -169,6 +169,14 @@ public function setObjectUrlOption($key, $value)
         return $this;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function clear($cachePrefix)
+    {
+        // TODO: implement cache clearing for Amazon S3 service
+    }
+
     /**
      * Returns the object path within the bucket.
      *

Imagine/Cache/Resolver/ResolverInterface.php

@@ -53,4 +53,13 @@ function getBrowserPath($targetPath, $filter, $absolute = false);
      * @return bool Whether the file has been removed successfully.
      */
     function remove($targetPath, $filter);
+
+    /**
+     * Clear the CacheResolver cache
+     *
+     * @param string $cachePrefix The cache prefix as defined in the configuration
+     *
+     * @return void
+     */
+    function clear($cachePrefix);
 }

Imagine/Cache/Resolver/WebPathResolver.php

@@ -7,7 +7,8 @@
 
 use Symfony\Component\HttpFoundation\Request,
     Symfony\Component\HttpFoundation\RedirectResponse,
-    Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
+    Symfony\Component\HttpKernel\Exception\NotFoundHttpException,
+    Symfony\Component\Finder\Finder;
 
 class WebPathResolver extends AbstractFilesystemResolver implements CacheManagerAwareInterface
 {
@@ -61,6 +62,24 @@ public function getBrowserPath($targetPath, $filter, $absolute = false)
         );
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function clear($cachePrefix)
+    {
+        // Let's just avoid to remove the web/ directory content if cache prefix is empty
+        if ($cachePrefix === '') {
+            throw new \InvalidArgumentException("Cannot clear the Imagine cache because the cache_prefix is empty in your config.");
+        }
+
+        $cachePath = $this->cacheManager->getWebRoot() . DIRECTORY_SEPARATOR . $cachePrefix;
+
+        // Avoid an exception if the cache path does not exist (i.e. Imagine didn't yet render any image)
+        if (is_dir($cachePath)) {
+            $this->filesystem->remove(Finder::create()->in($cachePath)->depth(0)->directories());
+        }
+    }
+
     /**
      * {@inheritDoc}
      */

README.md

@@ -500,6 +500,13 @@ liip_imagine:
 For an example of a cache resolver implementation, refer to
 `Liip\ImagineBundle\Imagine\Cache\Resolver\WebPathResolver`.
 
+### Cache cleaner
+
+Custom cache resolver classes must implement the ```clear``` method, at worst doing nothing.
+
+When the ```console cache:clear``` command is run, the clear method of all the registered cache
+resolvers is automatically called.
+
 ### AmazonS3Resolver
 
 The AmazonS3Resolver requires the [aws-sdk-php](/~https://github.com/amazonwebservices/aws-sdk-for-php).

Resources/config/imagine.xml

@@ -48,6 +48,10 @@
         <parameter key="liip_imagine.cache.resolver.web_path.class">Liip\ImagineBundle\Imagine\Cache\Resolver\WebPathResolver</parameter>
         <parameter key="liip_imagine.cache.resolver.no_cache.class">Liip\ImagineBundle\Imagine\Cache\Resolver\NoCacheResolver</parameter>
 
+        <!-- Cache clearers' classes -->
+
+        <parameter key="liip_imagine.cache.clearer.class">Liip\ImagineBundle\Imagine\Cache\CacheClearer</parameter>
+
     </parameters>
 
     <services>
@@ -152,5 +156,13 @@
             <argument type="service" id="filesystem" />
         </service>
 
+        <!-- Cache Clearer -->
+
+        <service id="liip_imagine.cache.clearer" class="%liip_imagine.cache.clearer.class%">
+            <tag name="kernel.cache_clearer" />
+            <argument type="service" id="liip_imagine.cache.manager" />
+            <argument>%liip_imagine.cache_prefix%</argument>
+        </service>
+
     </services>
 </container>