includes/cache/ResourceFileCache.php

   1 <?php
   2 /**
   3  * ResourceLoader request result caching in the file system.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23
  24 /**
  25  * ResourceLoader request result caching in the file system.
  26  *
  27  * @ingroup Cache
  28  */
  29 class ResourceFileCache extends FileCacheBase {
  30         protected $mCacheWorthy;
  31
  32         /* @todo configurable? */
  33         const MISS_THRESHOLD = 360; // 6/min * 60 min
  34
  35         /**
  36          * Construct an ResourceFileCache from a context
  37          * @param ResourceLoaderContext $context
  38          * @return ResourceFileCache
  39          */
  40         public static function newFromContext( ResourceLoaderContext $context ) {
  41                 $cache = new self();
  42
  43                 if ( $context->getImage() ) {
  44                         $cache->mType = 'image';
  45                 } elseif ( $context->getOnly() === 'styles' ) {
  46                         $cache->mType = 'css';
  47                 } else {
  48                         $cache->mType = 'js';
  49                 }
  50                 $modules = array_unique( $context->getModules() ); // remove duplicates
  51                 sort( $modules ); // normalize the order (permutation => combination)
  52                 $cache->mKey = sha1( $context->getHash() . implode( '|', $modules ) );
  53                 if ( count( $modules ) == 1 ) {
  54                         $cache->mCacheWorthy = true; // won't take up much space
  55                 }
  56
  57                 return $cache;
  58         }
  59
  60         /**
  61          * Check if an RL request can be cached.
  62          * Caller is responsible for checking if any modules are private.
  63          * @param ResourceLoaderContext $context
  64          * @return bool
  65          */
  66         public static function useFileCache( ResourceLoaderContext $context ) {
  67                 global $wgUseFileCache, $wgDefaultSkin, $wgLanguageCode;
  68                 if ( !$wgUseFileCache ) {
  69                         return false;
  70                 }
  71                 // Get all query values
  72                 $queryVals = $context->getRequest()->getValues();
  73                 foreach ( $queryVals as $query => $val ) {
  74                         if ( in_array( $query, array( 'modules', 'image', 'variant', 'version', '*' ) ) ) {
  75                                 // Use file cache regardless of the value of this parameter
  76                                 continue; // note: &* added as IE fix
  77                         } elseif ( $query === 'skin' && $val === $wgDefaultSkin ) {
  78                                 continue;
  79                         } elseif ( $query === 'lang' && $val === $wgLanguageCode ) {
  80                                 continue;
  81                         } elseif ( $query === 'only' && in_array( $val, array( 'styles', 'scripts' ) ) ) {
  82                                 continue;
  83                         } elseif ( $query === 'debug' && $val === 'false' ) {
  84                                 continue;
  85                         } elseif ( $query === 'format' && $val === 'rasterized' ) {
  86                                 continue;
  87                         }
  88
  89                         return false;
  90                 }
  91
  92                 return true; // cacheable
  93         }
  94
  95         /**
  96          * Get the base file cache directory
  97          * @return string
  98          */
  99         protected function cacheDirectory() {
 100                 return $this->baseCacheDirectory() . '/resources';
 101         }
 102
 103         /**
 104          * Item has many recent cache misses
 105          * @return bool
 106          */
 107         public function isCacheWorthy() {
 108                 if ( $this->mCacheWorthy === null ) {
 109                         $this->mCacheWorthy = (
 110                                 $this->isCached() || // even stale cache indicates it was cache worthy
 111                                 $this->getMissesRecent() >= self::MISS_THRESHOLD // many misses
 112                         );
 113                 }
 114
 115                 return $this->mCacheWorthy;
 116         }
 117 }