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