Your IP : 216.73.216.54
<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @author Roan Kattouw
* @author Trevor Parscal
*/
namespace MediaWiki\ResourceLoader;
use MediaWiki\Json\FormatJson;
use MediaWiki\MediaWikiServices;
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use Wikimedia\ObjectCache\WANObjectCache;
use Wikimedia\Rdbms\Database;
/**
* This class generates message blobs for use by ResourceLoader.
*
* A message blob is a JSON object containing the interface messages for a
* certain module in a certain language.
*
* @ingroup ResourceLoader
* @since 1.17
*/
class MessageBlobStore implements LoggerAwareInterface {
/** @var ResourceLoader */
private $resourceloader;
/** @var LoggerInterface */
protected $logger;
/** @var WANObjectCache */
protected $wanCache;
/**
* @param ResourceLoader $rl
* @param LoggerInterface|null $logger
* @param WANObjectCache|null $wanObjectCache
*/
public function __construct(
ResourceLoader $rl,
?LoggerInterface $logger,
?WANObjectCache $wanObjectCache
) {
$this->resourceloader = $rl;
$this->logger = $logger ?: new NullLogger();
// NOTE: when changing this assignment, make sure the code in the instantiator for
// LocalisationCache which calls MessageBlobStore::clearGlobalCacheEntry() uses the
// same cache object.
$this->wanCache = $wanObjectCache ?: MediaWikiServices::getInstance()
->getMainWANObjectCache();
}
/**
* @since 1.27
* @param LoggerInterface $logger
*/
public function setLogger( LoggerInterface $logger ) {
$this->logger = $logger;
}
/**
* Get the message blob for a module
*
* @since 1.27
* @param Module $module
* @param string $lang Language code
* @return string JSON
*/
public function getBlob( Module $module, $lang ) {
$blobs = $this->getBlobs( [ $module->getName() => $module ], $lang );
return $blobs[$module->getName()];
}
/**
* Get the message blobs for a set of modules
*
* @since 1.27
* @param Module[] $modules Array of module objects keyed by name
* @param string $lang Language code
* @return string[] An array mapping module names to message blobs
*/
public function getBlobs( array $modules, $lang ) {
// Each cache key for a message blob by module name and language code also has a generic
// check key without language code. This is used to invalidate any and all language subkeys
// that exist for a module from the updateMessage() method.
$checkKeys = [
self::makeGlobalPurgeKey( $this->wanCache )
];
$cacheKeys = [];
foreach ( $modules as $name => $module ) {
$cacheKey = $this->makeBlobCacheKey( $name, $lang, $module );
$cacheKeys[$name] = $cacheKey;
$checkKeys[$cacheKey][] = $this->makeModulePurgeKey( $name );
}
$curTTLs = [];
$result = $this->wanCache->getMulti( array_values( $cacheKeys ), $curTTLs, $checkKeys );
$blobs = [];
foreach ( $modules as $name => $module ) {
$key = $cacheKeys[$name];
if ( !isset( $result[$key] ) || $curTTLs[$key] === null || $curTTLs[$key] < 0 ) {
$blobs[$name] = $this->recacheMessageBlob( $key, $module, $lang );
} else {
// Use unexpired cache
$blobs[$name] = $result[$key];
}
}
return $blobs;
}
/**
* Global check key for ::clear()
*
* @param WANObjectCache $cache
* @return string Cache key
*/
private static function makeGlobalPurgeKey( WANObjectCache $cache ) {
return $cache->makeGlobalKey( 'resourceloader-messageblob' );
}
/**
* Per-module check key, for ::updateMessage()
*
* @param string $name
* @return string Cache key
*/
private function makeModulePurgeKey( $name ) {
return $this->wanCache->makeKey( 'resourceloader-messageblob', $name );
}
/**
* @param string $name
* @param string $lang
* @param Module $module
* @return string Cache key
*/
private function makeBlobCacheKey( $name, $lang, Module $module ) {
$messages = array_values( array_unique( $module->getMessages() ) );
sort( $messages );
return $this->wanCache->makeKey( 'resourceloader-messageblob',
$name,
$lang,
md5( json_encode( $messages ) )
);
}
/**
* @since 1.27
* @param string $cacheKey
* @param Module $module
* @param string $lang
* @return string JSON blob
*/
protected function recacheMessageBlob( $cacheKey, Module $module, $lang ) {
$blob = $this->generateMessageBlob( $module, $lang );
$cache = $this->wanCache;
$dbr = MediaWikiServices::getInstance()->getConnectionProvider()->getReplicaDatabase();
$cache->set( $cacheKey, $blob,
// Add part of a day to TTL to avoid all modules expiring at once
$cache::TTL_WEEK + mt_rand( 0, $cache::TTL_DAY ),
Database::getCacheSetOptions( $dbr )
);
return $blob;
}
/**
* Invalidate cache keys for modules using this message key.
* Called by MessageCache when a message has changed.
*
* @param string $key Message key
*/
public function updateMessage( $key ): void {
$moduleNames = $this->resourceloader->getModulesByMessage( $key );
foreach ( $moduleNames as $moduleName ) {
// Use the default holdoff TTL to account for database replica DB lag
// which can affect MessageCache.
$this->wanCache->touchCheckKey( $this->makeModulePurgeKey( $moduleName ) );
}
}
/**
* Invalidate cache keys for all known modules.
*
* Used by purgeMessageBlobStore.php
*/
public function clear() {
self::clearGlobalCacheEntry( $this->wanCache );
}
/**
* Invalidate cache keys for all known modules.
*
* Used by LocalisationCache and DatabaseUpdater after regenerating l10n cache.
*
* @param WANObjectCache $cache
*/
public static function clearGlobalCacheEntry( WANObjectCache $cache ) {
// Disable holdoff TTL because:
// - LocalisationCache is populated by messages on-disk and don't have DB lag,
// thus there is no need for hold off. We only clear it after new localisation
// updates are known to be deployed to all servers.
// - This global check key invalidates message blobs for all modules for all wikis
// in cache contexts (e.g. languages, skins). Setting a hold-off on this key could
// cause a cache stampede since no values would be stored for several seconds.
$cache->touchCheckKey( self::makeGlobalPurgeKey( $cache ), $cache::HOLDOFF_TTL_NONE );
}
/**
* @since 1.27
* @param string $key Message key
* @param string $lang Language code
* @return string|null
*/
protected function fetchMessage( $key, $lang ) {
$message = wfMessage( $key )->inLanguage( $lang );
if ( !$message->exists() ) {
$this->logger->warning( 'Failed to find {messageKey} ({lang})', [
'messageKey' => $key,
'lang' => $lang,
] );
$value = null;
} else {
$value = $message->plain();
}
return $value;
}
/**
* Generate the message blob for a given module in a given language.
*
* @param Module $module
* @param string $lang Language code
* @return string JSON blob
*/
private function generateMessageBlob( Module $module, $lang ) {
$messages = [];
foreach ( $module->getMessages() as $key ) {
$value = $this->fetchMessage( $key, $lang );
// If the message does not exist, omit it from the blob so that
// client-side mw.message may do its own existence handling.
if ( $value !== null ) {
$messages[$key] = $value;
}
}
$json = FormatJson::encode( (object)$messages, false, FormatJson::UTF8_OK );
// @codeCoverageIgnoreStart
if ( $json === false ) {
$this->logger->warning( 'Failed to encode message blob for {module} ({lang})', [
'module' => $module->getName(),
'lang' => $lang,
] );
$json = '{}';
}
// codeCoverageIgnoreEnd
return $json;
}
}