includes/cache/HtmlCacheUpdater.php

   1 <?php
   2 /**
   3  * HTML/file cache invalidation of cacheable variant/action URLs for a page
   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  * Class to invalidate the HTML/file cache of cacheable variant/action URLs for a page
  26  *
  27  * @ingroup Cache
  28  * @since 1.34
  29  */
  30 class HtmlCacheUpdater {
  31         /** @var int Purge after the main transaction round and respect $wgCdnReboundPurgeDelay */
  32         const ISOLATION_AND_LAG_AWARE = 1;
  33         /** @var int Purge immediately and only once (ignore $wgCdnReboundPurgeDelay) */
  34         const IMMEDIATE_WITHOUT_REBOUND = 2;
  35
  36         /**
  37          * Purge CDN/HTMLFileCache for a URL, Title, or iteratable of URL or Title entries
  38          *
  39          * String entries will be treated as URLs to be purged from the CDN layer.
  40          * For Title entries, all cacheable canonical URLs associated with the page
  41          * will be purged from the CDN and HTMLFileCache.
  42          *
  43          * The cache purges are queued as PRESEND deferred updates so that they run after the
  44          * main database transaction round of LBFactory. This reduces the chance of race conditions
  45          * where a stale value is re-populated before commit. Depending on $wgCdnReboundPurgeDelay,
  46          * a secondary set of purges might be issued several seconds later through the use of a
  47          * delayed job. This is used to mitigate the effects of DB replication lag as well as
  48          * multiple layers of CDN proxies. All deferred CDN purges are combined and de-duplicated
  49          * into a single DeferrableUpdate instance. This improves HTTP PURGE request pipelining.
  50          *
  51          * Use the IMMEDIATE_WITHOUT_REBOUND class constant to instantly issue the purges instead
  52          * and skip the use of any secondary purges regardless of $wgCdnReboundPurgeDelay.
  53          *
  54          * @param Traversable|Title[]|Title|string[]|string $entries
  55          * @param int $mode ISOLATION_AND_LAG_AWARE or IMMEDIATE_WITHOUT_REBOUND class constant
  56          */
  57         public function purge( $entries, $mode = self::ISOLATION_AND_LAG_AWARE ) {
  58                 $urls = [];
  59                 $titles = [];
  60                 if ( is_string( $entries ) ) {
  61                         $urls = [ $entries ];
  62                 } elseif ( $entries instanceof Title ) {
  63                         $titles = [ $entries ];
  64                 } elseif ( $entries instanceof TitleArray ) {
  65                         $titles = $entries; // save memory
  66                 } else {
  67                         foreach ( $entries as $entry ) {
  68                                 if ( is_string( $entry ) ) {
  69                                         $urls[] = $entry;
  70                                 } else {
  71                                         $titles[] = $entry;
  72                                 }
  73                         }
  74                 }
  75
  76                 if ( $mode === self::IMMEDIATE_WITHOUT_REBOUND ) {
  77                         HTMLFileCache::clearFileCache( $titles );
  78                         foreach ( $titles as $title ) {
  79                                 /** @var Title $title */
  80                                 $urls = array_merge( $urls, $title->getCdnUrls() );
  81                         }
  82                         CdnCacheUpdate::purge( $urls ); // purge once (no "rebound" purges)
  83                 } else {
  84                         DeferredUpdates::addUpdate(
  85                                 HtmlFileCacheUpdate::newFromTitles( $titles ),
  86                                 DeferredUpdates::PRESEND
  87                         );
  88                         DeferredUpdates::addUpdate(
  89                                 CdnCacheUpdate::newFromTitles( $titles, $urls ),
  90                                 DeferredUpdates::PRESEND
  91                         );
  92                 }
  93         }
  94 }