includes/resourceloader/MessageBlobStore.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  * @author Roan Kattouw
  20  * @author Trevor Parscal
  21  */
  22
  23 use MediaWiki\MediaWikiServices;
  24 use Psr\Log\LoggerAwareInterface;
  25 use Psr\Log\LoggerInterface;
  26 use Psr\Log\NullLogger;
  27 use Wikimedia\Rdbms\Database;
  28
  29 /**
  30  * This class generates message blobs for use by ResourceLoader.
  31  *
  32  * A message blob is a JSON object containing the interface messages for a
  33  * certain module in a certain language.
  34  *
  35  * @ingroup ResourceLoader
  36  * @since 1.17
  37  */
  38 class MessageBlobStore implements LoggerAwareInterface {
  39
  40         /* @var ResourceLoader */
  41         private $resourceloader;
  42
  43         /**
  44          * @var LoggerInterface
  45          */
  46         protected $logger;
  47
  48         /**
  49          * @var WANObjectCache
  50          */
  51         protected $wanCache;
  52
  53         /**
  54          * @param ResourceLoader $rl
  55          * @param LoggerInterface|null $logger
  56          */
  57         public function __construct( ResourceLoader $rl, LoggerInterface $logger = null ) {
  58                 $this->resourceloader = $rl;
  59                 $this->logger = $logger ?: new NullLogger();
  60                 $this->wanCache = MediaWikiServices::getInstance()->getMainWANObjectCache();
  61         }
  62
  63         /**
  64          * @since 1.27
  65          * @param LoggerInterface $logger
  66          */
  67         public function setLogger( LoggerInterface $logger ) {
  68                 $this->logger = $logger;
  69         }
  70
  71         /**
  72          * Get the message blob for a module
  73          *
  74          * @since 1.27
  75          * @param ResourceLoaderModule $module
  76          * @param string $lang Language code
  77          * @return string JSON
  78          */
  79         public function getBlob( ResourceLoaderModule $module, $lang ) {
  80                 $blobs = $this->getBlobs( [ $module->getName() => $module ], $lang );
  81                 return $blobs[$module->getName()];
  82         }
  83
  84         /**
  85          * Get the message blobs for a set of modules
  86          *
  87          * @since 1.27
  88          * @param ResourceLoaderModule[] $modules Array of module objects keyed by name
  89          * @param string $lang Language code
  90          * @return array An array mapping module names to message blobs
  91          */
  92         public function getBlobs( array $modules, $lang ) {
  93                 // Each cache key for a message blob by module name and language code also has a generic
  94                 // check key without language code. This is used to invalidate any and all language subkeys
  95                 // that exist for a module from the updateMessage() method.
  96                 $cache = $this->wanCache;
  97                 $checkKeys = [
  98                         // Global check key, see clear()
  99                         $cache->makeGlobalKey( __CLASS__ )
 100                 ];
 101                 $cacheKeys = [];
 102                 foreach ( $modules as $name => $module ) {
 103                         $cacheKey = $this->makeCacheKey( $module, $lang );
 104                         $cacheKeys[$name] = $cacheKey;
 105                         // Per-module check key, see updateMessage()
 106                         $checkKeys[$cacheKey][] = $cache->makeKey( __CLASS__, $name );
 107                 }
 108                 $curTTLs = [];
 109                 $result = $cache->getMulti( array_values( $cacheKeys ), $curTTLs, $checkKeys );
 110
 111                 $blobs = [];
 112                 foreach ( $modules as $name => $module ) {
 113                         $key = $cacheKeys[$name];
 114                         if ( !isset( $result[$key] ) || $curTTLs[$key] === null || $curTTLs[$key] < 0 ) {
 115                                 $blobs[$name] = $this->recacheMessageBlob( $key, $module, $lang );
 116                         } else {
 117                                 // Use unexpired cache
 118                                 $blobs[$name] = $result[$key];
 119                         }
 120                 }
 121                 return $blobs;
 122         }
 123
 124         /**
 125          * @since 1.27
 126          * @param ResourceLoaderModule $module
 127          * @param string $lang
 128          * @return string Cache key
 129          */
 130         private function makeCacheKey( ResourceLoaderModule $module, $lang ) {
 131                 $messages = array_values( array_unique( $module->getMessages() ) );
 132                 sort( $messages );
 133                 return $this->wanCache->makeKey( __CLASS__, $module->getName(), $lang,
 134                         md5( json_encode( $messages ) )
 135                 );
 136         }
 137
 138         /**
 139          * @since 1.27
 140          * @param string $cacheKey
 141          * @param ResourceLoaderModule $module
 142          * @param string $lang
 143          * @return string JSON blob
 144          */
 145         protected function recacheMessageBlob( $cacheKey, ResourceLoaderModule $module, $lang ) {
 146                 $blob = $this->generateMessageBlob( $module, $lang );
 147                 $cache = $this->wanCache;
 148                 $cache->set( $cacheKey, $blob,
 149                         // Add part of a day to TTL to avoid all modules expiring at once
 150                         $cache::TTL_WEEK + mt_rand( 0, $cache::TTL_DAY ),
 151                         Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) )
 152                 );
 153                 return $blob;
 154         }
 155
 156         /**
 157          * Invalidate cache keys for modules using this message key.
 158          * Called by MessageCache when a message has changed.
 159          *
 160          * @param string $key Message key
 161          */
 162         public function updateMessage( $key ) {
 163                 $moduleNames = $this->getResourceLoader()->getModulesByMessage( $key );
 164                 foreach ( $moduleNames as $moduleName ) {
 165                         // Uses a holdoff to account for database replica DB lag (for MessageCache)
 166                         $this->wanCache->touchCheckKey( $this->wanCache->makeKey( __CLASS__, $moduleName ) );
 167                 }
 168         }
 169
 170         /**
 171          * Invalidate cache keys for all known modules.
 172          * Called by LocalisationCache after cache is regenerated.
 173          */
 174         public function clear() {
 175                 $cache = $this->wanCache;
 176                 // Disable hold-off because:
 177                 // - LocalisationCache is populated by messages on-disk and don't have DB lag,
 178                 //   thus there is no need for hold off. We only clear it after new localisation
 179                 //   updates are known to be deployed to all servers.
 180                 // - This global check key invalidates message blobs for all modules for all wikis
 181                 //   in cache contexts (e.g. languages, skins). Setting a hold-off on this key could
 182                 //   cause a cache stampede since no values would be stored for several seconds.
 183                 $cache->touchCheckKey( $cache->makeGlobalKey( __CLASS__ ), $cache::HOLDOFF_TTL_NONE );
 184         }
 185
 186         /**
 187          * @since 1.27
 188          * @return ResourceLoader
 189          */
 190         protected function getResourceLoader() {
 191                 return $this->resourceloader;
 192         }
 193
 194         /**
 195          * @since 1.27
 196          * @param string $key Message key
 197          * @param string $lang Language code
 198          * @return string|null
 199          */
 200         protected function fetchMessage( $key, $lang ) {
 201                 $message = wfMessage( $key )->inLanguage( $lang );
 202                 if ( !$message->exists() ) {
 203                         $this->logger->warning( 'Failed to find {messageKey} ({lang})', [
 204                                 'messageKey' => $key,
 205                                 'lang' => $lang,
 206                         ] );
 207                         $value = null;
 208                 } else {
 209                         $value = $message->plain();
 210                 }
 211                 return $value;
 212         }
 213
 214         /**
 215          * Generate the message blob for a given module in a given language.
 216          *
 217          * @param ResourceLoaderModule $module
 218          * @param string $lang Language code
 219          * @return string JSON blob
 220          */
 221         private function generateMessageBlob( ResourceLoaderModule $module, $lang ) {
 222                 $messages = [];
 223                 foreach ( $module->getMessages() as $key ) {
 224                         $value = $this->fetchMessage( $key, $lang );
 225                         if ( $value !== null ) {
 226                                 $messages[$key] = $value;
 227                         }
 228                 }
 229
 230                 $json = FormatJson::encode( (object)$messages, false, FormatJson::UTF8_OK );
 231                 // @codeCoverageIgnoreStart
 232                 if ( $json === false ) {
 233                         $this->logger->warning( 'Failed to encode message blob for {module} ({lang})', [
 234                                 'module' => $module->getName(),
 235                                 'lang' => $lang,
 236                         ] );
 237                         $json = '{}';
 238                 }
 239                 // codeCoverageIgnoreEnd
 240                 return $json;
 241         }
 242 }