includes/cache/MessageBlobStore.php

   1 <?php
   2 /**
   3  * Message blobs storage used by ResourceLoader.
   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  * @author Roan Kattouw
  22  * @author Trevor Parscal
  23  * @author Timo Tijhof
  24  */
  25
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\LoggerInterface;
  28 use Psr\Log\NullLogger;
  29 use Wikimedia\Rdbms\Database;
  30
  31 /**
  32  * This class generates message blobs for use by ResourceLoader modules.
  33  *
  34  * A message blob is a JSON object containing the interface messages for a certain module in
  35  * a certain language.
  36  */
  37 class MessageBlobStore implements LoggerAwareInterface {
  38
  39         /* @var ResourceLoader|null */
  40         private $resourceloader;
  41
  42         /**
  43          * @var LoggerInterface
  44          */
  45         protected $logger;
  46
  47         /**
  48          * @var WANObjectCache
  49          */
  50         protected $wanCache;
  51
  52         /**
  53          * @param ResourceLoader $rl
  54          * @param LoggerInterface $logger
  55          */
  56         public function __construct( ResourceLoader $rl = null, LoggerInterface $logger = null ) {
  57                 $this->resourceloader = $rl;
  58                 $this->logger = $logger ?: new NullLogger();
  59                 $this->wanCache = ObjectCache::getMainWANInstance();
  60         }
  61
  62         /**
  63          * @since 1.27
  64          * @param LoggerInterface $logger
  65          */
  66         public function setLogger( LoggerInterface $logger ) {
  67                 $this->logger = $logger;
  68         }
  69
  70         /**
  71          * Get the message blob for a module
  72          *
  73          * @since 1.27
  74          * @param ResourceLoaderModule $module
  75          * @param string $lang Language code
  76          * @return string JSON
  77          */
  78         public function getBlob( ResourceLoaderModule $module, $lang ) {
  79                 $blobs = $this->getBlobs( [ $module->getName() => $module ], $lang );
  80                 return $blobs[$module->getName()];
  81         }
  82
  83         /**
  84          * Get the message blobs for a set of modules
  85          *
  86          * @since 1.27
  87          * @param ResourceLoaderModule[] $modules Array of module objects keyed by name
  88          * @param string $lang Language code
  89          * @return array An array mapping module names to message blobs
  90          */
  91         public function getBlobs( array $modules, $lang ) {
  92                 // Each cache key for a message blob by module name and language code also has a generic
  93                 // check key without language code. This is used to invalidate any and all language subkeys
  94                 // that exist for a module from the updateMessage() method.
  95                 $cache = $this->wanCache;
  96                 $checkKeys = [
  97                         // Global check key, see clear()
  98                         $cache->makeKey( __CLASS__ )
  99                 ];
 100                 $cacheKeys = [];
 101                 foreach ( $modules as $name => $module ) {
 102                         $cacheKey = $this->makeCacheKey( $module, $lang );
 103                         $cacheKeys[$name] = $cacheKey;
 104                         // Per-module check key, see updateMessage()
 105                         $checkKeys[$cacheKey][] = $cache->makeKey( __CLASS__, $name );
 106                 }
 107                 $curTTLs = [];
 108                 $result = $cache->getMulti( array_values( $cacheKeys ), $curTTLs, $checkKeys );
 109
 110                 $blobs = [];
 111                 foreach ( $modules as $name => $module ) {
 112                         $key = $cacheKeys[$name];
 113                         if ( !isset( $result[$key] ) || $curTTLs[$key] === null || $curTTLs[$key] < 0 ) {
 114                                 $blobs[$name] = $this->recacheMessageBlob( $key, $module, $lang );
 115                         } else {
 116                                 // Use unexpired cache
 117                                 $blobs[$name] = $result[$key];
 118                         }
 119                 }
 120                 return $blobs;
 121         }
 122
 123         /**
 124          * @deprecated since 1.27 Use getBlobs() instead
 125          * @return array
 126          */
 127         public function get( ResourceLoader $resourceLoader, $modules, $lang ) {
 128                 return $this->getBlobs( $modules, $lang );
 129         }
 130
 131         /**
 132          * @deprecated since 1.27 Obsolete. Used to populate a cache table in the database.
 133          * @return bool
 134          */
 135         public function insertMessageBlob( $name, ResourceLoaderModule $module, $lang ) {
 136                 return false;
 137         }
 138
 139         /**
 140          * @since 1.27
 141          * @param ResourceLoaderModule $module
 142          * @param string $lang
 143          * @return string Cache key
 144          */
 145         private function makeCacheKey( ResourceLoaderModule $module, $lang ) {
 146                 $messages = array_values( array_unique( $module->getMessages() ) );
 147                 sort( $messages );
 148                 return $this->wanCache->makeKey( __CLASS__, $module->getName(), $lang,
 149                         md5( json_encode( $messages ) )
 150                 );
 151         }
 152
 153         /**
 154          * @since 1.27
 155          * @param string $cacheKey
 156          * @param ResourceLoaderModule $module
 157          * @param string $lang
 158          * @return string JSON blob
 159          */
 160         protected function recacheMessageBlob( $cacheKey, ResourceLoaderModule $module, $lang ) {
 161                 $blob = $this->generateMessageBlob( $module, $lang );
 162                 $cache = $this->wanCache;
 163                 $cache->set( $cacheKey, $blob,
 164                         // Add part of a day to TTL to avoid all modules expiring at once
 165                         $cache::TTL_WEEK + mt_rand( 0, $cache::TTL_DAY ),
 166                         Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) )
 167                 );
 168                 return $blob;
 169         }
 170
 171         /**
 172          * Invalidate cache keys for modules using this message key.
 173          * Called by MessageCache when a message has changed.
 174          *
 175          * @param string $key Message key
 176          */
 177         public function updateMessage( $key ) {
 178                 $moduleNames = $this->getResourceLoader()->getModulesByMessage( $key );
 179                 foreach ( $moduleNames as $moduleName ) {
 180                         // Uses a holdoff to account for database replica DB lag (for MessageCache)
 181                         $this->wanCache->touchCheckKey( $this->wanCache->makeKey( __CLASS__, $moduleName ) );
 182                 }
 183         }
 184
 185         /**
 186          * Invalidate cache keys for all known modules.
 187          * Called by LocalisationCache after cache is regenerated.
 188          */
 189         public function clear() {
 190                 $cache = $this->wanCache;
 191                 // Disable holdoff because this invalidates all modules and also not needed since
 192                 // LocalisationCache is stored outside the database and doesn't have lag.
 193                 $cache->touchCheckKey( $cache->makeKey( __CLASS__ ), $cache::HOLDOFF_NONE );
 194         }
 195
 196         /**
 197          * @since 1.27
 198          * @return ResourceLoader
 199          */
 200         protected function getResourceLoader() {
 201                 // Back-compat: This class supports instantiation without a ResourceLoader object.
 202                 // Lazy-initialise this property because most callers don't need it.
 203                 if ( $this->resourceloader === null ) {
 204                         $this->logger->warning( __CLASS__ . ' created without a ResourceLoader instance' );
 205                         $this->resourceloader = new ResourceLoader();
 206                 }
 207                 return $this->resourceloader;
 208         }
 209
 210         /**
 211          * @since 1.27
 212          * @param string $key Message key
 213          * @param string $lang Language code
 214          * @return string
 215          */
 216         protected function fetchMessage( $key, $lang ) {
 217                 $message = wfMessage( $key )->inLanguage( $lang );
 218                 $value = $message->plain();
 219                 if ( !$message->exists() ) {
 220                         $this->logger->warning( 'Failed to find {messageKey} ({lang})', [
 221                                 'messageKey' => $key,
 222                                 'lang' => $lang,
 223                         ] );
 224                 }
 225                 return $value;
 226         }
 227
 228         /**
 229          * Generate the message blob for a given module in a given language.
 230          *
 231          * @param ResourceLoaderModule $module
 232          * @param string $lang Language code
 233          * @return string JSON blob
 234          */
 235         private function generateMessageBlob( ResourceLoaderModule $module, $lang ) {
 236                 $messages = [];
 237                 foreach ( $module->getMessages() as $key ) {
 238                         $messages[$key] = $this->fetchMessage( $key, $lang );
 239                 }
 240
 241                 $json = FormatJson::encode( (object)$messages );
 242                 // @codeCoverageIgnoreStart
 243                 if ( $json === false ) {
 244                         $this->logger->warning( 'Failed to encode message blob for {module} ({lang})', [
 245                                 'module' => $module->getName(),
 246                                 'lang' => $lang,
 247                         ] );
 248                         $json = '{}';
 249                 }
 250                 // codeCoverageIgnoreEnd
 251                 return $json;
 252         }
 253 }