Current File : //www/varak.net/wiki.varak.net/includes/cache/MessageBlobStore.php
<?php
/**
* Message blobs storage used by ResourceLoader.
*
* 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
* @author Timo Tijhof
*/
use Psr\Log\LoggerAwareInterface;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use Wikimedia\Rdbms\Database;
/**
* This class generates message blobs for use by ResourceLoader modules.
*
* A message blob is a JSON object containing the interface messages for a certain module in
* a certain language.
*/
class MessageBlobStore implements LoggerAwareInterface {
/* @var ResourceLoader|null */
private $resourceloader;
/**
* @var LoggerInterface
*/
protected $logger;
/**
* @var WANObjectCache
*/
protected $wanCache;
/**
* @param ResourceLoader|null $rl
* @param LoggerInterface|null $logger
*/
public function __construct( ResourceLoader $rl = null, LoggerInterface $logger = null ) {
$this->resourceloader = $rl;
$this->logger = $logger ?: new NullLogger();
$this->wanCache = ObjectCache::getMainWANInstance();
}
/**
* @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 ResourceLoaderModule $module
* @param string $lang Language code
* @return string JSON
*/
public function getBlob( ResourceLoaderModule $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 ResourceLoaderModule[] $modules Array of module objects keyed by name
* @param string $lang Language code
* @return array 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.
$cache = $this->wanCache;
$checkKeys = [
// Global check key, see clear()
$cache->makeKey( __CLASS__ )
];
$cacheKeys = [];
foreach ( $modules as $name => $module ) {
$cacheKey = $this->makeCacheKey( $module, $lang );
$cacheKeys[$name] = $cacheKey;
// Per-module check key, see updateMessage()
$checkKeys[$cacheKey][] = $cache->makeKey( __CLASS__, $name );
}
$curTTLs = [];
$result = $cache->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;
}
/**
* @deprecated since 1.27 Use getBlobs() instead
* @return array
*/
public function get( ResourceLoader $resourceLoader, $modules, $lang ) {
return $this->getBlobs( $modules, $lang );
}
/**
* @since 1.27
* @param ResourceLoaderModule $module
* @param string $lang
* @return string Cache key
*/
private function makeCacheKey( ResourceLoaderModule $module, $lang ) {
$messages = array_values( array_unique( $module->getMessages() ) );
sort( $messages );
return $this->wanCache->makeKey( __CLASS__, $module->getName(), $lang,
md5( json_encode( $messages ) )
);
}
/**
* @since 1.27
* @param string $cacheKey
* @param ResourceLoaderModule $module
* @param string $lang
* @return string JSON blob
*/
protected function recacheMessageBlob( $cacheKey, ResourceLoaderModule $module, $lang ) {
$blob = $this->generateMessageBlob( $module, $lang );
$cache = $this->wanCache;
$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( wfGetDB( DB_REPLICA ) )
);
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 ) {
$moduleNames = $this->getResourceLoader()->getModulesByMessage( $key );
foreach ( $moduleNames as $moduleName ) {
// Uses a holdoff to account for database replica DB lag (for MessageCache)
$this->wanCache->touchCheckKey( $this->wanCache->makeKey( __CLASS__, $moduleName ) );
}
}
/**
* Invalidate cache keys for all known modules.
* Called by LocalisationCache after cache is regenerated.
*/
public function clear() {
$cache = $this->wanCache;
// Disable holdoff because this invalidates all modules and also not needed since
// LocalisationCache is stored outside the database and doesn't have lag.
$cache->touchCheckKey( $cache->makeKey( __CLASS__ ), $cache::HOLDOFF_NONE );
}
/**
* @since 1.27
* @return ResourceLoader
*/
protected function getResourceLoader() {
// Back-compat: This class supports instantiation without a ResourceLoader object.
// Lazy-initialise this property because most callers don't need it.
if ( $this->resourceloader === null ) {
$this->logger->warning( __CLASS__ . ' created without a ResourceLoader instance' );
$this->resourceloader = new ResourceLoader();
}
return $this->resourceloader;
}
/**
* @since 1.27
* @param string $key Message key
* @param string $lang Language code
* @return string
*/
protected function fetchMessage( $key, $lang ) {
$message = wfMessage( $key )->inLanguage( $lang );
$value = $message->plain();
if ( !$message->exists() ) {
$this->logger->warning( 'Failed to find {messageKey} ({lang})', [
'messageKey' => $key,
'lang' => $lang,
] );
}
return $value;
}
/**
* Generate the message blob for a given module in a given language.
*
* @param ResourceLoaderModule $module
* @param string $lang Language code
* @return string JSON blob
*/
private function generateMessageBlob( ResourceLoaderModule $module, $lang ) {
$messages = [];
foreach ( $module->getMessages() as $key ) {
$messages[$key] = $this->fetchMessage( $key, $lang );
}
$json = FormatJson::encode( (object)$messages );
// @codeCoverageIgnoreStart
if ( $json === false ) {
$this->logger->warning( 'Failed to encode message blob for {module} ({lang})', [
'module' => $module->getName(),
'lang' => $lang,
] );
$json = '{}';
}
// codeCoverageIgnoreEnd
return $json;
}
}
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