includes/ParserCache.php

   1 <?php
   2 /**
   3  *
   4  * @package MediaWiki
   5  * @subpackage Cache
   6  */
   7
   8 /**
   9  *
  10  * @package MediaWiki
  11  */
  12 class ParserCache {
  13         /**
  14          * Setup a cache pathway with a given back-end storage mechanism.
  15          * May be a memcached client or a BagOStuff derivative.
  16          *
  17          * @param object $memCached
  18          */
  19         function ParserCache( &$memCached ) {
  20                 $this->mMemc =& $memCached;
  21         }
  22
  23         function getKey( &$article, &$user ) {
  24                 global $wgDBname, $action;
  25                 $hash = $user->getPageRenderingHash();
  26                 $pageid = intval( $article->getID() );
  27                 $renderkey = (int)($action == 'render');
  28                 $key = "$wgDBname:pcache:idhash:$pageid-$renderkey!$hash";
  29                 return $key;
  30         }
  31
  32         function getETag( &$article, &$user ) {
  33                 return 'W/"' . $this->getKey($article, $user) . "--" . $article->mTouched. '"';
  34         }
  35
  36         function get( &$article, &$user ) {
  37                 global $wgCacheEpoch;
  38                 $fname = 'ParserCache::get';
  39                 wfProfileIn( $fname );
  40
  41                 $hash = $user->getPageRenderingHash();
  42                 $pageid = intval( $article->getID() );
  43                 $key = $this->getKey( $article, $user );
  44
  45                 wfDebug( "Trying parser cache $key\n" );
  46                 $value = $this->mMemc->get( $key );
  47                 if ( is_object( $value ) ) {
  48                         wfDebug( "Found.\n" );
  49                         # Delete if article has changed since the cache was made
  50                         $canCache = $article->checkTouched();
  51                         $cacheTime = $value->getCacheTime();
  52                         $touched = $article->mTouched;
  53                         if ( !$canCache || $value->expired( $touched ) ) {
  54                                 if ( !$canCache ) {
  55                                         wfIncrStats( "pcache_miss_invalid" );
  56                                         wfDebug( "Invalid cached redirect, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
  57                                 } else {
  58                                         wfIncrStats( "pcache_miss_expired" );
  59                                         wfDebug( "Key expired, touched $touched, epoch $wgCacheEpoch, cached $cacheTime\n" );
  60                                 }
  61                                 $this->mMemc->delete( $key );
  62                                 $value = false;
  63
  64                         } else {
  65                                 wfIncrStats( "pcache_hit" );
  66                         }
  67                 } else {
  68                         wfDebug( "Parser cache miss.\n" );
  69                         wfIncrStats( "pcache_miss_absent" );
  70                         $value = false;
  71                 }
  72
  73                 wfProfileOut( $fname );
  74                 return $value;
  75         }
  76
  77         function save( $parserOutput, &$article, &$user ){
  78                 $key = $this->getKey( $article, $user );
  79                 $now = wfTimestampNow();
  80                 $parserOutput->setCacheTime( $now );
  81                 $parserOutput->mText .= "\n<!-- Saved in parser cache with key $key and timestamp $now -->\n";
  82                 wfDebug( "Saved in parser cache with key $key and timestamp $now\n" );
  83
  84                 if( $parserOutput->containsOldMagic() ){
  85                         $expire = 3600; # 1 hour
  86                 } else {
  87                         $expire = 86400; # 1 day
  88                 }
  89                 $this->mMemc->set( $key, $parserOutput, $expire );
  90         }
  91 }
  92
  93
  94 ?>