Introduce deep hashing on asset combiner

Added cms.enableAssetDeepHashing config item, disabled by default
Recompile assets
Refs #2248
Refs https://github.com/octobercms/library/pull/225

config/cms.php

@@ -166,6 +166,20 @@ return [
 
     'enableAssetMinify' => null,
 
+    /*
+    |--------------------------------------------------------------------------
+    | Check import timestamps when combining assets
+    |--------------------------------------------------------------------------
+    |
+    | If deep hashing is enabled, the combiner cache will be reset when a change
+    | is detected on imported files, in addition to those referenced directly.
+    | This will cause slower page performance. If set to null, assets are
+    | minified, when debug mode (app.debug) is disabled.
+    |
+    */
+
+    'enableAssetDeepHashing' => false,
+
     /*
     |--------------------------------------------------------------------------
     | Public plugins path

modules/system/classes/CombineAssets.php

@@ -14,6 +14,7 @@ use Assetic\Asset\FileAsset;
 use Assetic\Asset\GlobAsset;
 use Assetic\Asset\AssetCache;
 use Assetic\Asset\AssetCollection;
+use Assetic\Factory\AssetFactory;
 use October\Rain\Parse\Assetic\FilesystemCache;
 use System\Helpers\Cache as CacheHelper;
 use ApplicationException;
@@ -75,6 +76,12 @@ class CombineAssets
      */
     public $useMinify = false;
 
+    /**
+     * @var bool When true, cache will be busted when an import is modified.
+     * Enabling this feature will make page loading slower.
+     */
+    public $useDeepHashing = false;
+
     /**
      * @var array Cache of registration callbacks.
      */
@@ -90,11 +97,16 @@ class CombineAssets
          */
         $this->useCache = Config::get('cms.enableAssetCache', false);
         $this->useMinify = Config::get('cms.enableAssetMinify', null);
+        $this->useDeepHashing = Config::get('cms.enableAssetDeepHashing', null);
 
         if ($this->useMinify === null) {
             $this->useMinify = !Config::get('app.debug', false);
         }
 
+        if ($this->useDeepHashing === null) {
+            $this->useDeepHashing = Config::get('app.debug', false);
+        }
+
         /*
          * Register JavaScript filters
          */
@@ -176,6 +188,8 @@ class CombineAssets
         $this->localPath = $cacheInfo['path'];
         $this->storagePath = storage_path('cms/combiner/assets');
 
+        $this->setHashOnCombinerFilters($cacheKey);
+
         $combiner = $this->prepareCombiner($cacheInfo['files']);
         $contents = $combiner->dump();
         $mime = ($cacheInfo['extension'] == 'css') ? 'text/css' : 'application/javascript';
@@ -292,8 +306,11 @@ class CombineAssets
         $cacheInfo = $this->useCache ? $this->getCache($cacheKey) : false;
 
         if (!$cacheInfo) {
+            $this->setHashOnCombinerFilters($cacheKey);
+
             $combiner = $this->prepareCombiner($assets);
-            $lastMod = $combiner->getLastModified();
+            $factory = new AssetFactory($this->localPath);
+            $lastMod = $factory->getLastModified($combiner);
 
             $cacheInfo = [
                 'version'   => $cacheKey.'-'.$lastMod,
@@ -354,6 +371,44 @@ class CombineAssets
         return $cachedCollection;
     }
 
+    /**
+     * Busts the cache based on a different cache key.
+     * @return void
+     */
+    protected function setHashOnCombinerFilters($hash)
+    {
+        $allFilters = call_user_func_array('array_merge', $this->getFilters());
+
+        foreach ($allFilters as $filter) {
+            if (method_exists($filter, 'setHash')) {
+                $filter->setHash($hash);
+            }
+        }
+    }
+
+    /**
+     * Returns a deep hash on filters that support it.
+     * @return void
+     */
+    protected function getDeepHashFromAssets($assets)
+    {
+        $key = '';
+
+        $allFilters = call_user_func_array('array_merge', $this->getFilters());
+
+        $assetFiles = array_map(function($file) {
+            return $this->localPath.'/'.$file;
+        }, $assets);
+
+        foreach ($allFilters as $filter) {
+            if (method_exists($filter, 'hashFromAssets')) {
+                $key .= $filter->hashFromAssets($assetFiles, $this->localPath);
+            }
+        }
+
+        return $key;
+    }
+
     /**
      * Returns the URL used for accessing the combined files.
      * @param string $outputFilename A custom file name to use.
@@ -663,6 +718,13 @@ class CombineAssets
     {
         $cacheKey = $this->localPath . implode('|', $assets);
 
+        /*
+         * Deep hashing
+         */
+        if ($this->useDeepHashing) {
+            $cacheKey .= $this->getDeepHashFromAssets($assets);
+        }
+
         /*
          * Extensibility
          */