3 * Localisation messages cache.
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.
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.
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
23 use MediaWiki\MediaWikiServices
;
24 use Wikimedia\ScopedCallback
;
25 use MediaWiki\Logger\LoggerFactory
;
26 use Wikimedia\Rdbms\Database
;
29 * MediaWiki message cache structure version.
30 * Bump this whenever the message cache format has changed.
32 define( 'MSG_CACHE_VERSION', 2 );
36 * Performs various MediaWiki namespace-related functions
40 const FOR_UPDATE
= 1; // force message reload
42 /** How long to wait for memcached locks */
44 /** How long memcached locks last */
48 * Process local cache of loaded messages that are defined in
49 * MediaWiki namespace. First array level is a language code,
50 * second level is message key and the values are either message
51 * content prefixed with space, or !NONEXISTENT for negative
58 * @var bool[] Map of (language code => boolean)
60 protected $mCacheVolatile = [];
63 * Should mean that database cannot be used, but check
69 * Lifetime for cache, used by object caching.
70 * Set on construction, see __construct().
75 * Message cache has its own parser which it uses to transform messages
78 protected $mParserOptions;
83 * Variable for tracking which variables are already loaded
84 * @var array $mLoadedLanguages
86 protected $mLoadedLanguages = [];
89 * @var bool $mInParser
91 protected $mInParser = false;
93 /** @var WANObjectCache */
96 protected $clusterCache;
103 * @var MessageCache $instance
105 private static $instance;
108 * Get the signleton instance of this class
111 * @return MessageCache
113 public static function singleton() {
114 if ( self
::$instance === null ) {
115 global $wgUseDatabaseMessages, $wgMsgCacheExpiry, $wgUseLocalMessageCache;
116 self
::$instance = new self(
117 MediaWikiServices
::getInstance()->getMainWANObjectCache(),
118 wfGetMessageCacheStorage(),
119 $wgUseLocalMessageCache
120 ? MediaWikiServices
::getInstance()->getLocalServerObjectCache()
121 : new EmptyBagOStuff(),
122 $wgUseDatabaseMessages,
127 return self
::$instance;
131 * Destroy the singleton instance
135 public static function destroyInstance() {
136 self
::$instance = null;
140 * Normalize message key input
142 * @param string $key Input message key to be normalized
143 * @return string Normalized message key
145 public static function normalizeKey( $key ) {
148 $lckey = strtr( $key, ' ', '_' );
149 if ( ord( $lckey ) < 128 ) {
150 $lckey[0] = strtolower( $lckey[0] );
152 $lckey = $wgContLang->lcfirst( $lckey );
159 * @param WANObjectCache $wanCache
160 * @param BagOStuff $clusterCache
161 * @param BagOStuff $serverCache
162 * @param bool $useDB Whether to look for message overrides (e.g. MediaWiki: pages)
163 * @param int $expiry Lifetime for cache. @see $mExpiry.
165 public function __construct(
166 WANObjectCache
$wanCache,
167 BagOStuff
$clusterCache,
168 BagOStuff
$serverCache,
172 $this->wanCache
= $wanCache;
173 $this->clusterCache
= $clusterCache;
174 $this->srvCache
= $serverCache;
176 $this->mDisable
= !$useDB;
177 $this->mExpiry
= $expiry;
181 * ParserOptions is lazy initialised.
183 * @return ParserOptions
185 function getParserOptions() {
188 if ( !$this->mParserOptions
) {
189 if ( !$wgUser->isSafeToLoad() ) {
190 // $wgUser isn't unstubbable yet, so don't try to get a
191 // ParserOptions for it. And don't cache this ParserOptions
193 $po = ParserOptions
::newFromAnon();
194 $po->setAllowUnsafeRawHtml( false );
198 $this->mParserOptions
= new ParserOptions
;
199 // Messages may take parameters that could come
200 // from malicious sources. As a precaution, disable
201 // the <html> parser tag when parsing messages.
202 $this->mParserOptions
->setAllowUnsafeRawHtml( false );
205 return $this->mParserOptions
;
209 * Try to load the cache from APC.
211 * @param string $code Optional language code, see documenation of load().
212 * @return array|bool The cache array, or false if not in cache.
214 protected function getLocalCache( $code ) {
215 $cacheKey = $this->srvCache
->makeKey( __CLASS__
, $code );
217 return $this->srvCache
->get( $cacheKey );
221 * Save the cache to APC.
223 * @param string $code
224 * @param array $cache The cache array
226 protected function saveToLocalCache( $code, $cache ) {
227 $cacheKey = $this->srvCache
->makeKey( __CLASS__
, $code );
228 $this->srvCache
->set( $cacheKey, $cache );
232 * Loads messages from caches or from database in this order:
233 * (1) local message cache (if $wgUseLocalMessageCache is enabled)
235 * (3) from the database.
237 * When succesfully loading from (2) or (3), all higher level caches are
238 * updated for the newest version.
240 * Nothing is loaded if member variable mDisable is true, either manually
241 * set by calling code or if message loading fails (is this possible?).
243 * Returns true if cache is already populated or it was succesfully populated,
244 * or false if populating empty cache fails. Also returns true if MessageCache
247 * @param string $code Language to which load messages
248 * @param int $mode Use MessageCache::FOR_UPDATE to skip process cache [optional]
249 * @throws MWException
252 protected function load( $code, $mode = null ) {
253 if ( !is_string( $code ) ) {
254 throw new InvalidArgumentException( "Missing language code" );
257 # Don't do double loading...
258 if ( isset( $this->mLoadedLanguages
[$code] ) && $mode != self
::FOR_UPDATE
) {
262 # 8 lines of code just to say (once) that message cache is disabled
263 if ( $this->mDisable
) {
264 static $shownDisabled = false;
265 if ( !$shownDisabled ) {
266 wfDebug( __METHOD__
. ": disabled\n" );
267 $shownDisabled = true;
273 # Loading code starts
274 $success = false; # Keep track of success
275 $staleCache = false; # a cache array with expired data, or false if none has been loaded
276 $where = []; # Debug info, delayed to avoid spamming debug log too much
278 # Hash of the contents is stored in memcache, to detect if data-center cache
279 # or local cache goes out of date (e.g. due to replace() on some other server)
280 list( $hash, $hashVolatile ) = $this->getValidationHash( $code );
281 $this->mCacheVolatile
[$code] = $hashVolatile;
283 # Try the local cache and check against the cluster hash key...
284 $cache = $this->getLocalCache( $code );
286 $where[] = 'local cache is empty';
287 } elseif ( !isset( $cache['HASH'] ) ||
$cache['HASH'] !== $hash ) {
288 $where[] = 'local cache has the wrong hash';
289 $staleCache = $cache;
290 } elseif ( $this->isCacheExpired( $cache ) ) {
291 $where[] = 'local cache is expired';
292 $staleCache = $cache;
293 } elseif ( $hashVolatile ) {
294 $where[] = 'local cache validation key is expired/volatile';
295 $staleCache = $cache;
297 $where[] = 'got from local cache';
299 $this->mCache
[$code] = $cache;
303 $cacheKey = $this->clusterCache
->makeKey( 'messages', $code ); # Key in memc for messages
304 # Try the global cache. If it is empty, try to acquire a lock. If
305 # the lock can't be acquired, wait for the other thread to finish
306 # and then try the global cache a second time.
307 for ( $failedAttempts = 0; $failedAttempts <= 1; $failedAttempts++
) {
308 if ( $hashVolatile && $staleCache ) {
309 # Do not bother fetching the whole cache blob to avoid I/O.
310 # Instead, just try to get the non-blocking $statusKey lock
311 # below, and use the local stale value if it was not acquired.
312 $where[] = 'global cache is presumed expired';
314 $cache = $this->clusterCache
->get( $cacheKey );
316 $where[] = 'global cache is empty';
317 } elseif ( $this->isCacheExpired( $cache ) ) {
318 $where[] = 'global cache is expired';
319 $staleCache = $cache;
320 } elseif ( $hashVolatile ) {
321 # DB results are replica DB lag prone until the holdoff TTL passes.
322 # By then, updates should be reflected in loadFromDBWithLock().
323 # One thread renerates the cache while others use old values.
324 $where[] = 'global cache is expired/volatile';
325 $staleCache = $cache;
327 $where[] = 'got from global cache';
328 $this->mCache
[$code] = $cache;
329 $this->saveToCaches( $cache, 'local-only', $code );
335 # Done, no need to retry
339 # We need to call loadFromDB. Limit the concurrency to one process.
340 # This prevents the site from going down when the cache expires.
341 # Note that the DB slam protection lock here is non-blocking.
342 $loadStatus = $this->loadFromDBWithLock( $code, $where, $mode );
343 if ( $loadStatus === true ) {
346 } elseif ( $staleCache ) {
347 # Use the stale cache while some other thread constructs the new one
348 $where[] = 'using stale cache';
349 $this->mCache
[$code] = $staleCache;
352 } elseif ( $failedAttempts > 0 ) {
353 # Already blocked once, so avoid another lock/unlock cycle.
354 # This case will typically be hit if memcached is down, or if
355 # loadFromDB() takes longer than LOCK_WAIT.
356 $where[] = "could not acquire status key.";
358 } elseif ( $loadStatus === 'cantacquire' ) {
359 # Wait for the other thread to finish, then retry. Normally,
360 # the memcached get() will then yeild the other thread's result.
361 $where[] = 'waited for other thread to complete';
362 $this->getReentrantScopedLock( $cacheKey );
364 # Disable cache; $loadStatus is 'disabled'
371 $where[] = 'loading FAILED - cache is disabled';
372 $this->mDisable
= true;
373 $this->mCache
= false;
374 wfDebugLog( 'MessageCacheError', __METHOD__
. ": Failed to load $code\n" );
375 # This used to throw an exception, but that led to nasty side effects like
376 # the whole wiki being instantly down if the memcached server died
378 # All good, just record the success
379 $this->mLoadedLanguages
[$code] = true;
382 $info = implode( ', ', $where );
383 wfDebugLog( 'MessageCache', __METHOD__
. ": Loading $code... $info\n" );
389 * @param string $code
390 * @param array &$where List of wfDebug() comments
391 * @param int $mode Use MessageCache::FOR_UPDATE to use DB_MASTER
392 * @return bool|string True on success or one of ("cantacquire", "disabled")
394 protected function loadFromDBWithLock( $code, array &$where, $mode = null ) {
395 # If cache updates on all levels fail, give up on message overrides.
396 # This is to avoid easy site outages; see $saveSuccess comments below.
397 $statusKey = $this->clusterCache
->makeKey( 'messages', $code, 'status' );
398 $status = $this->clusterCache
->get( $statusKey );
399 if ( $status === 'error' ) {
400 $where[] = "could not load; method is still globally disabled";
404 # Now let's regenerate
405 $where[] = 'loading from database';
407 # Lock the cache to prevent conflicting writes.
408 # This lock is non-blocking so stale cache can quickly be used.
409 # Note that load() will call a blocking getReentrantScopedLock()
410 # after this if it really need to wait for any current thread.
411 $cacheKey = $this->clusterCache
->makeKey( 'messages', $code );
412 $scopedLock = $this->getReentrantScopedLock( $cacheKey, 0 );
413 if ( !$scopedLock ) {
414 $where[] = 'could not acquire main lock';
415 return 'cantacquire';
418 $cache = $this->loadFromDB( $code, $mode );
419 $this->mCache
[$code] = $cache;
420 $saveSuccess = $this->saveToCaches( $cache, 'all', $code );
422 if ( !$saveSuccess ) {
424 * Cache save has failed.
426 * There are two main scenarios where this could be a problem:
427 * - The cache is more than the maximum size (typically 1MB compressed).
428 * - Memcached has no space remaining in the relevant slab class. This is
429 * unlikely with recent versions of memcached.
431 * Either way, if there is a local cache, nothing bad will happen. If there
432 * is no local cache, disabling the message cache for all requests avoids
433 * incurring a loadFromDB() overhead on every request, and thus saves the
434 * wiki from complete downtime under moderate traffic conditions.
436 if ( $this->srvCache
instanceof EmptyBagOStuff
) {
437 $this->clusterCache
->set( $statusKey, 'error', 60 * 5 );
438 $where[] = 'could not save cache, disabled globally for 5 minutes';
440 $where[] = "could not save global cache";
448 * Loads cacheable messages from the database. Messages bigger than
449 * $wgMaxMsgCacheEntrySize are assigned a special value, and are loaded
450 * on-demand from the database later.
452 * @param string $code Language code
453 * @param int $mode Use MessageCache::FOR_UPDATE to skip process cache
454 * @return array Loaded messages for storing in caches
456 protected function loadFromDB( $code, $mode = null ) {
457 global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;
459 // (T164666) The query here performs really poorly on WMF's
460 // contributions replicas. We don't have a way to say "any group except
461 // contributions", so for the moment let's specify 'api'.
462 // @todo: Get rid of this hack.
463 $dbr = wfGetDB( ( $mode == self
::FOR_UPDATE
) ? DB_MASTER
: DB_REPLICA
, 'api' );
469 'page_is_redirect' => 0,
470 'page_namespace' => NS_MEDIAWIKI
,
474 if ( $wgAdaptiveMessageCache && $code !== $wgLanguageCode ) {
475 if ( !isset( $this->mCache
[$wgLanguageCode] ) ) {
476 $this->load( $wgLanguageCode );
478 $mostused = array_keys( $this->mCache
[$wgLanguageCode] );
479 foreach ( $mostused as $key => $value ) {
480 $mostused[$key] = "$value/$code";
484 if ( count( $mostused ) ) {
485 $conds['page_title'] = $mostused;
486 } elseif ( $code !== $wgLanguageCode ) {
487 $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), '/', $code );
489 # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses
490 # other than language code.
491 $conds[] = 'page_title NOT' .
492 $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );
495 # Conditions to fetch oversized pages to ignore them
497 $bigConds[] = 'page_len > ' . intval( $wgMaxMsgCacheEntrySize );
499 # Load titles for all oversized pages in the MediaWiki namespace
502 [ 'page_title', 'page_latest' ],
504 __METHOD__
. "($code)-big"
506 foreach ( $res as $row ) {
507 $cache[$row->page_title
] = '!TOO BIG';
508 // At least include revision ID so page changes are reflected in the hash
509 $cache['EXCESSIVE'][$row->page_title
] = $row->page_latest
;
512 # Conditions to load the remaining pages with their contents
513 $smallConds = $conds;
514 $smallConds[] = 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize );
517 [ 'page', 'revision', 'text' ],
518 [ 'page_title', 'old_id', 'old_text', 'old_flags' ],
520 __METHOD__
. "($code)-small",
523 'revision' => [ 'JOIN', 'page_latest=rev_id' ],
524 'text' => [ 'JOIN', 'rev_text_id=old_id' ],
528 foreach ( $res as $row ) {
529 $text = Revision
::getRevisionText( $row );
530 if ( $text === false ) {
531 // Failed to fetch data; possible ES errors?
532 // Store a marker to fetch on-demand as a workaround...
533 // TODO Use a differnt marker
538 . ": failed to load message page text for {$row->page_title} ($code)"
541 $entry = ' ' . $text;
543 $cache[$row->page_title
] = $entry;
546 $cache['VERSION'] = MSG_CACHE_VERSION
;
549 # Hash for validating local cache (APC). No need to take into account
550 # messages larger than $wgMaxMsgCacheEntrySize, since those are only
551 # stored and fetched from memcache.
552 $cache['HASH'] = md5( serialize( $cache ) );
553 $cache['EXPIRY'] = wfTimestamp( TS_MW
, time() +
$this->mExpiry
);
559 * Updates cache as necessary when message page is changed
561 * @param string $title Message cache key with initial uppercase letter
562 * @param string|bool $text New contents of the page (false if deleted)
564 public function replace( $title, $text ) {
565 global $wgLanguageCode;
567 if ( $this->mDisable
) {
571 list( $msg, $code ) = $this->figureMessage( $title );
572 if ( strpos( $title, '/' ) !== false && $code === $wgLanguageCode ) {
573 // Content language overrides do not use the /<code> suffix
577 // (a) Update the process cache with the new message text
578 if ( $text === false ) {
580 $this->mCache
[$code][$title] = '!NONEXISTENT';
582 // Ignore $wgMaxMsgCacheEntrySize so the process cache is up to date
583 $this->mCache
[$code][$title] = ' ' . $text;
586 // (b) Update the shared caches in a deferred update with a fresh DB snapshot
587 DeferredUpdates
::addCallableUpdate(
588 function () use ( $title, $msg, $code ) {
589 global $wgContLang, $wgMaxMsgCacheEntrySize;
590 // Allow one caller at a time to avoid race conditions
591 $scopedLock = $this->getReentrantScopedLock(
592 $this->clusterCache
->makeKey( 'messages', $code )
594 if ( !$scopedLock ) {
595 LoggerFactory
::getInstance( 'MessageCache' )->error(
596 __METHOD__
. ': could not acquire lock to update {title} ({code})',
597 [ 'title' => $title, 'code' => $code ] );
600 // Load the messages from the master DB to avoid race conditions
601 $cache = $this->loadFromDB( $code, self
::FOR_UPDATE
);
602 $this->mCache
[$code] = $cache;
603 // Load the process cache values and set the per-title cache keys
604 $page = WikiPage
::factory( Title
::makeTitle( NS_MEDIAWIKI
, $title ) );
605 $page->loadPageData( $page::READ_LATEST
);
606 $text = $this->getMessageTextFromContent( $page->getContent() );
607 // Check if an individual cache key should exist and update cache accordingly
608 if ( is_string( $text ) && strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
609 $titleKey = $this->bigMessageCacheKey( $this->mCache
[$code]['HASH'], $title );
610 $this->wanCache
->set( $titleKey, ' ' . $text, $this->mExpiry
);
612 // Mark this cache as definitely being "latest" (non-volatile) so
613 // load() calls do try to refresh the cache with replica DB data
614 $this->mCache
[$code]['LATEST'] = time();
615 // Pre-emptively update the local datacenter cache so things like edit filter and
616 // blacklist changes are reflect immediately, as these often use MediaWiki: pages.
617 // The datacenter handling replace() calls should be the same one handling edits
618 // as they require HTTP POST.
619 $this->saveToCaches( $this->mCache
[$code], 'all', $code );
620 // Release the lock now that the cache is saved
621 ScopedCallback
::consume( $scopedLock );
623 // Relay the purge. Touching this check key expires cache contents
624 // and local cache (APC) validation hash across all datacenters.
625 $this->wanCache
->touchCheckKey( $this->wanCache
->makeKey( 'messages', $code ) );
626 // Also delete cached sidebar... just in case it is affected
627 // @TODO: shouldn't this be $code === $wgLanguageCode?
628 if ( $code === 'en' ) {
629 // Purge all language sidebars, e.g. on ?action=purge to the sidebar messages
630 $codes = array_keys( Language
::fetchLanguageNames() );
632 // Purge only the sidebar for this language
635 foreach ( $codes as $code ) {
636 $this->wanCache
->delete( $this->wanCache
->makeKey( 'sidebar', $code ) );
639 // Purge the message in the message blob store
640 $resourceloader = RequestContext
::getMain()->getOutput()->getResourceLoader();
641 $blobStore = $resourceloader->getMessageBlobStore();
642 $blobStore->updateMessage( $wgContLang->lcfirst( $msg ) );
644 Hooks
::run( 'MessageCacheReplace', [ $title, $text ] );
646 DeferredUpdates
::PRESEND
651 * Is the given cache array expired due to time passing or a version change?
653 * @param array $cache
656 protected function isCacheExpired( $cache ) {
657 if ( !isset( $cache['VERSION'] ) ||
!isset( $cache['EXPIRY'] ) ) {
660 if ( $cache['VERSION'] != MSG_CACHE_VERSION
) {
663 if ( wfTimestampNow() >= $cache['EXPIRY'] ) {
671 * Shortcut to update caches.
673 * @param array $cache Cached messages with a version.
674 * @param string $dest Either "local-only" to save to local caches only
675 * or "all" to save to all caches.
676 * @param string|bool $code Language code (default: false)
679 protected function saveToCaches( array $cache, $dest, $code = false ) {
680 if ( $dest === 'all' ) {
681 $cacheKey = $this->clusterCache
->makeKey( 'messages', $code );
682 $success = $this->clusterCache
->set( $cacheKey, $cache );
683 $this->setValidationHash( $code, $cache );
688 $this->saveToLocalCache( $code, $cache );
694 * Get the md5 used to validate the local APC cache
696 * @param string $code
697 * @return array (hash or false, bool expiry/volatility status)
699 protected function getValidationHash( $code ) {
701 $value = $this->wanCache
->get(
702 $this->wanCache
->makeKey( 'messages', $code, 'hash', 'v1' ),
704 [ $this->wanCache
->makeKey( 'messages', $code ) ]
708 $hash = $value['hash'];
709 if ( ( time() - $value['latest'] ) < WANObjectCache
::TTL_MINUTE
) {
710 // Cache was recently updated via replace() and should be up-to-date.
711 // That method is only called in the primary datacenter and uses FOR_UPDATE.
712 // Also, it is unlikely that the current datacenter is *now* secondary one.
715 // See if the "check" key was bumped after the hash was generated
716 $expired = ( $curTTL < 0 );
719 // No hash found at all; cache must regenerate to be safe
724 return [ $hash, $expired ];
728 * Set the md5 used to validate the local disk cache
730 * If $cache has a 'LATEST' UNIX timestamp key, then the hash will not
731 * be treated as "volatile" by getValidationHash() for the next few seconds.
732 * This is triggered when $cache is generated using FOR_UPDATE mode.
734 * @param string $code
735 * @param array $cache Cached messages with a version
737 protected function setValidationHash( $code, array $cache ) {
738 $this->wanCache
->set(
739 $this->wanCache
->makeKey( 'messages', $code, 'hash', 'v1' ),
741 'hash' => $cache['HASH'],
742 'latest' => isset( $cache['LATEST'] ) ?
$cache['LATEST'] : 0
744 WANObjectCache
::TTL_INDEFINITE
749 * @param string $key A language message cache key that stores blobs
750 * @param int $timeout Wait timeout in seconds
751 * @return null|ScopedCallback
753 protected function getReentrantScopedLock( $key, $timeout = self
::WAIT_SEC
) {
754 return $this->clusterCache
->getScopedLock( $key, $timeout, self
::LOCK_TTL
, __METHOD__
);
758 * Get a message from either the content language or the user language.
760 * First, assemble a list of languages to attempt getting the message from. This
761 * chain begins with the requested language and its fallbacks and then continues with
762 * the content language and its fallbacks. For each language in the chain, the following
763 * process will occur (in this order):
764 * 1. If a language-specific override, i.e., [[MW:msg/lang]], is available, use that.
765 * Note: for the content language, there is no /lang subpage.
766 * 2. Fetch from the static CDB cache.
767 * 3. If available, check the database for fallback language overrides.
769 * This process provides a number of guarantees. When changing this code, make sure all
770 * of these guarantees are preserved.
771 * * If the requested language is *not* the content language, then the CDB cache for that
772 * specific language will take precedence over the root database page ([[MW:msg]]).
773 * * Fallbacks will be just that: fallbacks. A fallback language will never be reached if
774 * the message is available *anywhere* in the language for which it is a fallback.
776 * @param string $key The message key
777 * @param bool $useDB If true, look for the message in the DB, false
778 * to use only the compiled l10n cache.
779 * @param bool|string|object $langcode Code of the language to get the message for.
780 * - If string and a valid code, will create a standard language object
781 * - If string but not a valid code, will create a basic language object
782 * - If boolean and false, create object from the current users language
783 * - If boolean and true, create object from the wikis content language
784 * - If language object, use it as given
785 * @param bool $isFullKey Specifies whether $key is a two part key "msg/lang".
787 * @throws MWException When given an invalid key
788 * @return string|bool False if the message doesn't exist, otherwise the
789 * message (which can be empty)
791 function get( $key, $useDB = true, $langcode = true, $isFullKey = false ) {
792 if ( is_int( $key ) ) {
793 // Fix numerical strings that somehow become ints
796 } elseif ( !is_string( $key ) ) {
797 throw new MWException( 'Non-string key given' );
798 } elseif ( $key === '' ) {
799 // Shortcut: the empty key is always missing
803 // For full keys, get the language code from the key
804 $pos = strrpos( $key, '/' );
805 if ( $isFullKey && $pos !== false ) {
806 $langcode = substr( $key, $pos +
1 );
807 $key = substr( $key, 0, $pos );
810 // Normalise title-case input (with some inlining)
811 $lckey = self
::normalizeKey( $key );
813 Hooks
::run( 'MessageCache::get', [ &$lckey ] );
815 // Loop through each language in the fallback list until we find something useful
816 $lang = wfGetLangObj( $langcode );
817 $message = $this->getMessageFromFallbackChain(
820 !$this->mDisable
&& $useDB
823 // If we still have no message, maybe the key was in fact a full key so try that
824 if ( $message === false ) {
825 $parts = explode( '/', $lckey );
826 // We may get calls for things that are http-urls from sidebar
827 // Let's not load nonexistent languages for those
828 // They usually have more than one slash.
829 if ( count( $parts ) == 2 && $parts[1] !== '' ) {
830 $message = Language
::getMessageFor( $parts[0], $parts[1] );
831 if ( $message === null ) {
837 // Post-processing if the message exists
838 if ( $message !== false ) {
840 $message = str_replace(
842 # Fix for trailing whitespace, removed by textarea
844 # Fix for NBSP, converted to space by firefox
863 * Given a language, try and fetch messages from that language.
865 * Will also consider fallbacks of that language, the site language, and fallbacks for
868 * @see MessageCache::get
869 * @param Language|StubObject $lang Preferred language
870 * @param string $lckey Lowercase key for the message (as for localisation cache)
871 * @param bool $useDB Whether to include messages from the wiki database
872 * @return string|bool The message, or false if not found
874 protected function getMessageFromFallbackChain( $lang, $lckey, $useDB ) {
879 // First try the requested language.
880 $message = $this->getMessageForLang( $lang, $lckey, $useDB, $alreadyTried );
881 if ( $message !== false ) {
885 // Now try checking the site language.
886 $message = $this->getMessageForLang( $wgContLang, $lckey, $useDB, $alreadyTried );
891 * Given a language, try and fetch messages from that language and its fallbacks.
893 * @see MessageCache::get
894 * @param Language|StubObject $lang Preferred language
895 * @param string $lckey Lowercase key for the message (as for localisation cache)
896 * @param bool $useDB Whether to include messages from the wiki database
897 * @param bool[] $alreadyTried Contains true for each language that has been tried already
898 * @return string|bool The message, or false if not found
900 private function getMessageForLang( $lang, $lckey, $useDB, &$alreadyTried ) {
903 $langcode = $lang->getCode();
905 // Try checking the database for the requested language
907 $uckey = $wgContLang->ucfirst( $lckey );
909 if ( !isset( $alreadyTried[ $langcode ] ) ) {
910 $message = $this->getMsgFromNamespace(
911 $this->getMessagePageName( $langcode, $uckey ),
915 if ( $message !== false ) {
918 $alreadyTried[ $langcode ] = true;
924 // Check the CDB cache
925 $message = $lang->getMessage( $lckey );
926 if ( $message !== null ) {
930 // Try checking the database for all of the fallback languages
932 $fallbackChain = Language
::getFallbacksFor( $langcode );
934 foreach ( $fallbackChain as $code ) {
935 if ( isset( $alreadyTried[ $code ] ) ) {
939 $message = $this->getMsgFromNamespace(
940 $this->getMessagePageName( $code, $uckey ), $code );
942 if ( $message !== false ) {
945 $alreadyTried[ $code ] = true;
953 * Get the message page name for a given language
955 * @param string $langcode
956 * @param string $uckey Uppercase key for the message
957 * @return string The page name
959 private function getMessagePageName( $langcode, $uckey ) {
960 global $wgLanguageCode;
962 if ( $langcode === $wgLanguageCode ) {
963 // Messages created in the content language will not have the /lang extension
966 return "$uckey/$langcode";
971 * Get a message from the MediaWiki namespace, with caching. The key must
972 * first be converted to two-part lang/msg form if necessary.
974 * Unlike self::get(), this function doesn't resolve fallback chains, and
975 * some callers require this behavior. LanguageConverter::parseCachedTable()
976 * and self::get() are some examples in core.
978 * @param string $title Message cache key with initial uppercase letter
979 * @param string $code Code denoting the language to try
980 * @return string|bool The message, or false if it does not exist or on error
982 public function getMsgFromNamespace( $title, $code ) {
983 $this->load( $code );
985 if ( isset( $this->mCache
[$code][$title] ) ) {
986 $entry = $this->mCache
[$code][$title];
987 if ( substr( $entry, 0, 1 ) === ' ' ) {
988 // The message exists, so make sure a string is returned.
989 return (string)substr( $entry, 1 );
990 } elseif ( $entry === '!NONEXISTENT' ) {
992 } elseif ( $entry === '!TOO BIG' ) {
993 // Fall through and try invididual message cache below
996 // XXX: This is not cached in process cache, should it?
998 Hooks
::run( 'MessagesPreLoad', [ $title, &$message, $code ] );
999 if ( $message !== false ) {
1006 // Individual message cache key
1007 $titleKey = $this->bigMessageCacheKey( $this->mCache
[$code]['HASH'], $title );
1009 if ( $this->mCacheVolatile
[$code] ) {
1011 // Make sure that individual keys respect the WAN cache holdoff period too
1012 LoggerFactory
::getInstance( 'MessageCache' )->debug(
1013 __METHOD__
. ': loading volatile key \'{titleKey}\'',
1014 [ 'titleKey' => $titleKey, 'code' => $code ] );
1016 // Try the individual message cache
1017 $entry = $this->wanCache
->get( $titleKey );
1020 if ( $entry !== false ) {
1021 if ( substr( $entry, 0, 1 ) === ' ' ) {
1022 $this->mCache
[$code][$title] = $entry;
1023 // The message exists, so make sure a string is returned
1024 return (string)substr( $entry, 1 );
1025 } elseif ( $entry === '!NONEXISTENT' ) {
1026 $this->mCache
[$code][$title] = '!NONEXISTENT';
1030 // Corrupt/obsolete entry, delete it
1031 $this->wanCache
->delete( $titleKey );
1035 // Try loading the message from the database
1036 $dbr = wfGetDB( DB_REPLICA
);
1037 $cacheOpts = Database
::getCacheSetOptions( $dbr );
1038 // Use newKnownCurrent() to avoid querying revision/user tables
1039 $titleObj = Title
::makeTitle( NS_MEDIAWIKI
, $title );
1040 if ( $titleObj->getLatestRevID() ) {
1041 $revision = Revision
::newKnownCurrent(
1050 $content = $revision->getContent();
1052 $message = $this->getMessageTextFromContent( $content );
1053 if ( is_string( $message ) ) {
1054 $this->mCache
[$code][$title] = ' ' . $message;
1055 $this->wanCache
->set( $titleKey, ' ' . $message, $this->mExpiry
, $cacheOpts );
1058 // A possibly temporary loading failure
1059 LoggerFactory
::getInstance( 'MessageCache' )->warning(
1060 __METHOD__
. ': failed to load message page text for \'{titleKey}\'',
1061 [ 'titleKey' => $titleKey, 'code' => $code ] );
1062 $message = null; // no negative caching
1065 $message = false; // negative caching
1068 if ( $message === false ) {
1069 // Negative caching in case a "too big" message is no longer available (deleted)
1070 $this->mCache
[$code][$title] = '!NONEXISTENT';
1071 $this->wanCache
->set( $titleKey, '!NONEXISTENT', $this->mExpiry
, $cacheOpts );
1078 * @param string $message
1079 * @param bool $interface
1080 * @param string $language Language code
1081 * @param Title $title
1084 function transform( $message, $interface = false, $language = null, $title = null ) {
1085 // Avoid creating parser if nothing to transform
1086 if ( strpos( $message, '{{' ) === false ) {
1090 if ( $this->mInParser
) {
1094 $parser = $this->getParser();
1096 $popts = $this->getParserOptions();
1097 $popts->setInterfaceMessage( $interface );
1098 $popts->setTargetLanguage( $language );
1100 $userlang = $popts->setUserLang( $language );
1101 $this->mInParser
= true;
1102 $message = $parser->transformMsg( $message, $popts, $title );
1103 $this->mInParser
= false;
1104 $popts->setUserLang( $userlang );
1113 function getParser() {
1114 global $wgParser, $wgParserConf;
1116 if ( !$this->mParser
&& isset( $wgParser ) ) {
1117 # Do some initialisation so that we don't have to do it twice
1118 $wgParser->firstCallInit();
1119 # Clone it and store it
1120 $class = $wgParserConf['class'];
1121 if ( $class == ParserDiffTest
::class ) {
1123 $this->mParser
= new $class( $wgParserConf );
1125 $this->mParser
= clone $wgParser;
1129 return $this->mParser
;
1133 * @param string $text
1134 * @param Title $title
1135 * @param bool $linestart Whether or not this is at the start of a line
1136 * @param bool $interface Whether this is an interface message
1137 * @param Language|string $language Language code
1138 * @return ParserOutput|string
1140 public function parse( $text, $title = null, $linestart = true,
1141 $interface = false, $language = null
1145 if ( $this->mInParser
) {
1146 return htmlspecialchars( $text );
1149 $parser = $this->getParser();
1150 $popts = $this->getParserOptions();
1151 $popts->setInterfaceMessage( $interface );
1153 if ( is_string( $language ) ) {
1154 $language = Language
::factory( $language );
1156 $popts->setTargetLanguage( $language );
1158 if ( !$title ||
!$title instanceof Title
) {
1159 wfDebugLog( 'GlobalTitleFail', __METHOD__
. ' called by ' .
1160 wfGetAllCallers( 6 ) . ' with no title set.' );
1163 // Sometimes $wgTitle isn't set either...
1165 # It's not uncommon having a null $wgTitle in scripts. See r80898
1166 # Create a ghost title in such case
1167 $title = Title
::makeTitle( NS_SPECIAL
, 'Badtitle/title not set in ' . __METHOD__
);
1170 $this->mInParser
= true;
1171 $res = $parser->parse( $text, $title, $popts, $linestart );
1172 $this->mInParser
= false;
1177 function disable() {
1178 $this->mDisable
= true;
1182 $this->mDisable
= false;
1186 * Whether DB/cache usage is disabled for determining messages
1188 * If so, this typically indicates either:
1189 * - a) load() failed to find a cached copy nor query the DB
1190 * - b) we are in a special context or error mode that cannot use the DB
1191 * If the DB is ignored, any derived HTML output or cached objects may be wrong.
1192 * To avoid long-term cache pollution, TTLs can be adjusted accordingly.
1197 public function isDisabled() {
1198 return $this->mDisable
;
1202 * Clear all stored messages. Mainly used after a mass rebuild.
1205 $langs = Language
::fetchLanguageNames( null, 'mw' );
1206 foreach ( array_keys( $langs ) as $code ) {
1207 # Global and local caches
1208 $this->wanCache
->touchCheckKey( $this->wanCache
->makeKey( 'messages', $code ) );
1211 $this->mLoadedLanguages
= [];
1215 * @param string $key
1218 public function figureMessage( $key ) {
1219 global $wgLanguageCode;
1221 $pieces = explode( '/', $key );
1222 if ( count( $pieces ) < 2 ) {
1223 return [ $key, $wgLanguageCode ];
1226 $lang = array_pop( $pieces );
1227 if ( !Language
::fetchLanguageName( $lang, null, 'mw' ) ) {
1228 return [ $key, $wgLanguageCode ];
1231 $message = implode( '/', $pieces );
1233 return [ $message, $lang ];
1237 * Get all message keys stored in the message cache for a given language.
1238 * If $code is the content language code, this will return all message keys
1239 * for which MediaWiki:msgkey exists. If $code is another language code, this
1240 * will ONLY return message keys for which MediaWiki:msgkey/$code exists.
1241 * @param string $code Language code
1242 * @return array Array of message keys (strings)
1244 public function getAllMessageKeys( $code ) {
1247 $this->load( $code );
1248 if ( !isset( $this->mCache
[$code] ) ) {
1249 // Apparently load() failed
1252 // Remove administrative keys
1253 $cache = $this->mCache
[$code];
1254 unset( $cache['VERSION'] );
1255 unset( $cache['EXPIRY'] );
1256 unset( $cache['EXCESSIVE'] );
1257 // Remove any !NONEXISTENT keys
1258 $cache = array_diff( $cache, [ '!NONEXISTENT' ] );
1260 // Keys may appear with a capital first letter. lcfirst them.
1261 return array_map( [ $wgContLang, 'lcfirst' ], array_keys( $cache ) );
1265 * Purge message caches when a MediaWiki: page is created, updated, or deleted
1267 * @param Title $title Message page title
1268 * @param Content|null $content New content for edit/create, null on deletion
1271 public function updateMessageOverride( Title
$title, Content
$content = null ) {
1274 $msgText = $this->getMessageTextFromContent( $content );
1275 if ( $msgText === null ) {
1276 $msgText = false; // treat as not existing
1279 $this->replace( $title->getDBkey(), $msgText );
1281 if ( $wgContLang->hasVariants() ) {
1282 $wgContLang->updateConversionTable( $title );
1287 * @param Content|null $content Content or null if the message page does not exist
1288 * @return string|bool|null Returns false if $content is null and null on error
1290 private function getMessageTextFromContent( Content
$content = null ) {
1291 // @TODO: could skip pseudo-messages like js/css here, based on content model
1293 // Message page exists...
1294 // XXX: Is this the right way to turn a Content object into a message?
1295 // NOTE: $content is typically either WikitextContent, JavaScriptContent or
1296 // CssContent. MessageContent is *not* used for storing messages, it's
1297 // only used for wrapping them when needed.
1298 $msgText = $content->getWikitextForTransclusion();
1299 if ( $msgText === false ||
$msgText === null ) {
1300 // This might be due to some kind of misconfiguration...
1302 LoggerFactory
::getInstance( 'MessageCache' )->warning(
1303 __METHOD__
. ": message content doesn't provide wikitext "
1304 . "(content model: " . $content->getModel() . ")" );
1307 // Message page does not exist...
1315 * @param string $hash Hash for this version of the entire key/value overrides map
1316 * @param string $title Message cache key with initial uppercase letter
1319 private function bigMessageCacheKey( $hash, $title ) {
1320 return $this->wanCache
->makeKey( 'messages-big', $hash, $title );