REL1_32/php/MessageCache_8php_source.html

<?php

use MediaWiki\MediaWikiServices;

use Wikimedia\ScopedCallback;

use MediaWiki\Logger\LoggerFactory;

use Wikimedia\Rdbms\Database;


define( 'MSG_CACHE_VERSION', 2 );


class MessageCache {

    const FOR_UPDATE = 1; // force message reload


    const WAIT_SEC = 15;

    const LOCK_TTL = 30;


    protected $cache;


    protected $overridable;


    protected $cacheVolatile = [];


    protected $mDisable;


    protected $mExpiry;


    protected $mParserOptions;

    protected $mParser;


    protected $mInParser = false;


    protected $wanCache;

    protected $clusterCache;

    protected $srvCache;

    protected $contLang;


    private $loadedLanguages = [];


    private static $instance;


    public static function singleton() {

        if ( self::$instance === null ) {

            global $wgUseDatabaseMessages, $wgMsgCacheExpiry, $wgUseLocalMessageCache;

            $services = MediaWikiServices::getInstance();

            self::$instance = new self(

                $services->getMainWANObjectCache(),

                wfGetMessageCacheStorage(),

                $wgUseLocalMessageCache

                    ? $services->getLocalServerObjectCache()

                    : new EmptyBagOStuff(),

                $wgUseDatabaseMessages,

                $wgMsgCacheExpiry,

                $services->getContentLanguage()

            );

        }


        return self::$instance;

    }


    public static function destroyInstance() {

        self::$instance = null;

    }


    public static function normalizeKey( $key ) {

        $lckey = strtr( $key, ' ', '_' );

        if ( ord( $lckey ) < 128 ) {

            $lckey[0] = strtolower( $lckey[0] );

        } else {

            $lckey = MediaWikiServices::getInstance()->getContentLanguage()->lcfirst( $lckey );

        }


        return $lckey;

    }


    public function __construct(

        WANObjectCache $wanCache,

        BagOStuff $clusterCache,

        BagOStuff $serverCache,

        $useDB,

        $expiry,

        Language $contLang = null

    ) {

        $this->wanCache = $wanCache;

        $this->clusterCache = $clusterCache;

        $this->srvCache = $serverCache;


        $this->cache = new MapCacheLRU( 5 ); // limit size for sanity


        $this->mDisable = !$useDB;

        $this->mExpiry = $expiry;

        $this->contLang = $contLang ?? MediaWikiServices::getInstance()->getContentLanguage();

    }


    function getParserOptions() {

        global $wgUser;


        if ( !$this->mParserOptions ) {

            if ( !$wgUser->isSafeToLoad() ) {

                // $wgUser isn't unstubbable yet, so don't try to get a

                // ParserOptions for it. And don't cache this ParserOptions

                // either.

                $po = ParserOptions::newFromAnon();

                $po->setAllowUnsafeRawHtml( false );

                return $po;

            }


            $this->mParserOptions = new ParserOptions;

            // Messages may take parameters that could come

            // from malicious sources. As a precaution, disable

            // the <html> parser tag when parsing messages.

            $this->mParserOptions->setAllowUnsafeRawHtml( false );

        }


        return $this->mParserOptions;

    }


    protected function getLocalCache( $code ) {

        $cacheKey = $this->srvCache->makeKey( __CLASS__, $code );


        return $this->srvCache->get( $cacheKey );

    }


    protected function saveToLocalCache( $code, $cache ) {

        $cacheKey = $this->srvCache->makeKey( __CLASS__, $code );

        $this->srvCache->set( $cacheKey, $cache );

    }


    protected function load( $code, $mode = null ) {

        if ( !is_string( $code ) ) {

            throw new InvalidArgumentException( "Missing language code" );

        }


        # Don't do double loading...

        if ( isset( $this->loadedLanguages[$code] ) && $mode != self::FOR_UPDATE ) {

            return true;

        }


        $this->overridable = array_flip( Language::getMessageKeysFor( $code ) );


        # 8 lines of code just to say (once) that message cache is disabled

        if ( $this->mDisable ) {

            static $shownDisabled = false;

            if ( !$shownDisabled ) {

                wfDebug( __METHOD__ . ": disabled\n" );

                $shownDisabled = true;

            }


            return true;

        }


        # Loading code starts

        $success = false; # Keep track of success

        $staleCache = false; # a cache array with expired data, or false if none has been loaded

        $where = []; # Debug info, delayed to avoid spamming debug log too much


        # Hash of the contents is stored in memcache, to detect if data-center cache

        # or local cache goes out of date (e.g. due to replace() on some other server)

        list( $hash, $hashVolatile ) = $this->getValidationHash( $code );

        $this->cacheVolatile[$code] = $hashVolatile;


        # Try the local cache and check against the cluster hash key...

        $cache = $this->getLocalCache( $code );

        if ( !$cache ) {

            $where[] = 'local cache is empty';

        } elseif ( !isset( $cache['HASH'] ) || $cache['HASH'] !== $hash ) {

            $where[] = 'local cache has the wrong hash';

            $staleCache = $cache;

        } elseif ( $this->isCacheExpired( $cache ) ) {

            $where[] = 'local cache is expired';

            $staleCache = $cache;

        } elseif ( $hashVolatile ) {

            $where[] = 'local cache validation key is expired/volatile';

            $staleCache = $cache;

        } else {

            $where[] = 'got from local cache';

            $this->cache->set( $code, $cache );

            $success = true;

        }


        if ( !$success ) {

            $cacheKey = $this->clusterCache->makeKey( 'messages', $code );

            # Try the global cache. If it is empty, try to acquire a lock. If

            # the lock can't be acquired, wait for the other thread to finish

            # and then try the global cache a second time.

            for ( $failedAttempts = 0; $failedAttempts <= 1; $failedAttempts++ ) {

                if ( $hashVolatile && $staleCache ) {

                    # Do not bother fetching the whole cache blob to avoid I/O.

                    # Instead, just try to get the non-blocking $statusKey lock

                    # below, and use the local stale value if it was not acquired.

                    $where[] = 'global cache is presumed expired';

                } else {

                    $cache = $this->clusterCache->get( $cacheKey );

                    if ( !$cache ) {

                        $where[] = 'global cache is empty';

                    } elseif ( $this->isCacheExpired( $cache ) ) {

                        $where[] = 'global cache is expired';

                        $staleCache = $cache;

                    } elseif ( $hashVolatile ) {

                        # DB results are replica DB lag prone until the holdoff TTL passes.

                        # By then, updates should be reflected in loadFromDBWithLock().

                        # One thread regenerates the cache while others use old values.

                        $where[] = 'global cache is expired/volatile';

                        $staleCache = $cache;

                    } else {

                        $where[] = 'got from global cache';

                        $this->cache->set( $code, $cache );

                        $this->saveToCaches( $cache, 'local-only', $code );

                        $success = true;

                    }

                }


                if ( $success ) {

                    # Done, no need to retry

                    break;

                }


                # We need to call loadFromDB. Limit the concurrency to one process.

                # This prevents the site from going down when the cache expires.

                # Note that the DB slam protection lock here is non-blocking.

                $loadStatus = $this->loadFromDBWithLock( $code, $where, $mode );

                if ( $loadStatus === true ) {

                    $success = true;

                    break;

                } elseif ( $staleCache ) {

                    # Use the stale cache while some other thread constructs the new one

                    $where[] = 'using stale cache';

                    $this->cache->set( $code, $staleCache );

                    $success = true;

                    break;

                } elseif ( $failedAttempts > 0 ) {

                    # Already blocked once, so avoid another lock/unlock cycle.

                    # This case will typically be hit if memcached is down, or if

                    # loadFromDB() takes longer than LOCK_WAIT.

                    $where[] = "could not acquire status key.";

                    break;

                } elseif ( $loadStatus === 'cantacquire' ) {

                    # Wait for the other thread to finish, then retry. Normally,

                    # the memcached get() will then yield the other thread's result.

                    $where[] = 'waited for other thread to complete';

                    $this->getReentrantScopedLock( $cacheKey );

                } else {

                    # Disable cache; $loadStatus is 'disabled'

                    break;

                }

            }

        }


        if ( !$success ) {

            $where[] = 'loading FAILED - cache is disabled';

            $this->mDisable = true;

            $this->cache->set( $code, [] );

            wfDebugLog( 'MessageCacheError', __METHOD__ . ": Failed to load $code\n" );

            # This used to throw an exception, but that led to nasty side effects like

            # the whole wiki being instantly down if the memcached server died

        } else {

            # All good, just record the success

            $this->loadedLanguages[$code] = true;

        }


        if ( !$this->cache->has( $code ) ) { // sanity

            throw new LogicException( "Process cache for '$code' should be set by now." );

        }


        $info = implode( ', ', $where );

        wfDebugLog( 'MessageCache', __METHOD__ . ": Loading $code... $info\n" );


        return $success;

    }


    protected function loadFromDBWithLock( $code, array &$where, $mode = null ) {

        # If cache updates on all levels fail, give up on message overrides.

        # This is to avoid easy site outages; see $saveSuccess comments below.

        $statusKey = $this->clusterCache->makeKey( 'messages', $code, 'status' );

        $status = $this->clusterCache->get( $statusKey );

        if ( $status === 'error' ) {

            $where[] = "could not load; method is still globally disabled";

            return 'disabled';

        }


        # Now let's regenerate

        $where[] = 'loading from database';


        # Lock the cache to prevent conflicting writes.

        # This lock is non-blocking so stale cache can quickly be used.

        # Note that load() will call a blocking getReentrantScopedLock()

        # after this if it really need to wait for any current thread.

        $cacheKey = $this->clusterCache->makeKey( 'messages', $code );

        $scopedLock = $this->getReentrantScopedLock( $cacheKey, 0 );

        if ( !$scopedLock ) {

            $where[] = 'could not acquire main lock';

            return 'cantacquire';

        }


        $cache = $this->loadFromDB( $code, $mode );

        $this->cache->set( $code, $cache );

        $saveSuccess = $this->saveToCaches( $cache, 'all', $code );


        if ( !$saveSuccess ) {

            if ( $this->srvCache instanceof EmptyBagOStuff ) {

                $this->clusterCache->set( $statusKey, 'error', 60 * 5 );

                $where[] = 'could not save cache, disabled globally for 5 minutes';

            } else {

                $where[] = "could not save global cache";

            }

        }


        return true;

    }


    protected function loadFromDB( $code, $mode = null ) {

        global $wgMaxMsgCacheEntrySize, $wgLanguageCode, $wgAdaptiveMessageCache;


        // (T164666) The query here performs really poorly on WMF's

        // contributions replicas. We don't have a way to say "any group except

        // contributions", so for the moment let's specify 'api'.

        // @todo: Get rid of this hack.

        $dbr = wfGetDB( ( $mode == self::FOR_UPDATE ) ? DB_MASTER : DB_REPLICA, 'api' );


        $cache = [];


        $mostused = []; // list of "<cased message key>/<code>"

        if ( $wgAdaptiveMessageCache && $code !== $wgLanguageCode ) {

            if ( !$this->cache->has( $wgLanguageCode ) ) {

                $this->load( $wgLanguageCode );

            }

            $mostused = array_keys( $this->cache->get( $wgLanguageCode ) );

            foreach ( $mostused as $key => $value ) {

                $mostused[$key] = "$value/$code";

            }

        }


        // Get the list of software-defined messages in core/extensions

        $overridable = array_flip( Language::getMessageKeysFor( $wgLanguageCode ) );


        // Common conditions

        $conds = [

            'page_is_redirect' => 0,

            'page_namespace' => NS_MEDIAWIKI,

        ];

        if ( count( $mostused ) ) {

            $conds['page_title'] = $mostused;

        } elseif ( $code !== $wgLanguageCode ) {

            $conds[] = 'page_title' . $dbr->buildLike( $dbr->anyString(), '/', $code );

        } else {

            # Effectively disallows use of '/' character in NS_MEDIAWIKI for uses

            # other than language code.

            $conds[] = 'page_title NOT' .

                $dbr->buildLike( $dbr->anyString(), '/', $dbr->anyString() );

        }


        // Set the stubs for oversized software-defined messages in the main cache map

        $res = $dbr->select(

            'page',

            [ 'page_title', 'page_latest' ],

            array_merge( $conds, [ 'page_len > ' . intval( $wgMaxMsgCacheEntrySize ) ] ),

            __METHOD__ . "($code)-big"

        );

        foreach ( $res as $row ) {

            $name = $this->contLang->lcfirst( $row->page_title );

            // Include entries/stubs for all keys in $mostused in adaptive mode

            if ( $wgAdaptiveMessageCache || $this->isMainCacheable( $name, $overridable ) ) {

                $cache[$row->page_title] = '!TOO BIG';

            }

            // At least include revision ID so page changes are reflected in the hash

            $cache['EXCESSIVE'][$row->page_title] = $row->page_latest;

        }


        // Set the text for small software-defined messages in the main cache map

        $res = $dbr->select(

            [ 'page', 'revision', 'text' ],

            [ 'page_title', 'page_latest', 'old_id', 'old_text', 'old_flags' ],

            array_merge( $conds, [ 'page_len <= ' . intval( $wgMaxMsgCacheEntrySize ) ] ),

            __METHOD__ . "($code)-small",

            [],

            [

                'revision' => [ 'JOIN', 'page_latest=rev_id' ],

                'text' => [ 'JOIN', 'rev_text_id=old_id' ],

            ]

        );

        foreach ( $res as $row ) {

            $name = $this->contLang->lcfirst( $row->page_title );

            // Include entries/stubs for all keys in $mostused in adaptive mode

            if ( $wgAdaptiveMessageCache || $this->isMainCacheable( $name, $overridable ) ) {

                $text = Revision::getRevisionText( $row );

                if ( $text === false ) {

                    // Failed to fetch data; possible ES errors?

                    // Store a marker to fetch on-demand as a workaround...

                    // TODO Use a differnt marker

                    $entry = '!TOO BIG';

                    wfDebugLog(

                        'MessageCache',

                        __METHOD__

                        . ": failed to load message page text for {$row->page_title} ($code)"

                    );

                } else {

                    $entry = ' ' . $text;

                }

                $cache[$row->page_title] = $entry;

            } else {

                // T193271: cache object gets too big and slow to generate.

                // At least include revision ID so page changes are reflected in the hash.

                $cache['EXCESSIVE'][$row->page_title] = $row->page_latest;

            }

        }


        $cache['VERSION'] = MSG_CACHE_VERSION;

        ksort( $cache );


        # Hash for validating local cache (APC). No need to take into account

        # messages larger than $wgMaxMsgCacheEntrySize, since those are only

        # stored and fetched from memcache.

        $cache['HASH'] = md5( serialize( $cache ) );

        $cache['EXPIRY'] = wfTimestamp( TS_MW, time() + $this->mExpiry );

        unset( $cache['EXCESSIVE'] ); // only needed for hash


        return $cache;

    }


    private function isMainCacheable( $name, array $overridable ) {

        // Include common conversion table pages. This also avoids problems with

        // Installer::parse() bailing out due to disallowed DB queries (T207979).

        return ( isset( $overridable[$name] ) || strpos( $name, 'conversiontable/' ) === 0 );

    }


    public function replace( $title, $text ) {

        global $wgLanguageCode;


        if ( $this->mDisable ) {

            return;

        }


        list( $msg, $code ) = $this->figureMessage( $title );

        if ( strpos( $title, '/' ) !== false && $code === $wgLanguageCode ) {

            // Content language overrides do not use the /<code> suffix

            return;

        }


        // (a) Update the process cache with the new message text

        if ( $text === false ) {

            // Page deleted

            $this->cache->setField( $code, $title, '!NONEXISTENT' );

        } else {

            // Ignore $wgMaxMsgCacheEntrySize so the process cache is up to date

            $this->cache->setField( $code, $title, ' ' . $text );

        }


        // (b) Update the shared caches in a deferred update with a fresh DB snapshot

        DeferredUpdates::addUpdate(

            new MessageCacheUpdate( $code, $title, $msg ),

            DeferredUpdates::PRESEND

        );

    }


    public function refreshAndReplaceInternal( $code, array $replacements ) {

        global $wgMaxMsgCacheEntrySize;


        // Allow one caller at a time to avoid race conditions

        $scopedLock = $this->getReentrantScopedLock(

            $this->clusterCache->makeKey( 'messages', $code )

        );

        if ( !$scopedLock ) {

            foreach ( $replacements as list( $title ) ) {

                LoggerFactory::getInstance( 'MessageCache' )->error(

                    __METHOD__ . ': could not acquire lock to update {title} ({code})',

                    [ 'title' => $title, 'code' => $code ] );

            }


            return;

        }


        // Load the existing cache to update it in the local DC cache.

        // The other DCs will see a hash mismatch.

        if ( $this->load( $code, self::FOR_UPDATE ) ) {

            $cache = $this->cache->get( $code );

        } else {

            // Err? Fall back to loading from the database.

            $cache = $this->loadFromDB( $code, self::FOR_UPDATE );

        }

        // Check if individual cache keys should exist and update cache accordingly

        $newTextByTitle = []; // map of (title => content)

        $newBigTitles = []; // map of (title => latest revision ID), like EXCESSIVE in loadFromDB()

        foreach ( $replacements as list( $title ) ) {

            $page = WikiPage::factory( Title::makeTitle( NS_MEDIAWIKI, $title ) );

            $page->loadPageData( $page::READ_LATEST );

            $text = $this->getMessageTextFromContent( $page->getContent() );

            // Remember the text for the blob store update later on

            $newTextByTitle[$title] = $text;

            // Note that if $text is false, then $cache should have a !NONEXISTANT entry

            if ( !is_string( $text ) ) {

                $cache[$title] = '!NONEXISTENT';

            } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {

                $cache[$title] = '!TOO BIG';

                $newBigTitles[$title] = $page->getLatest();

            } else {

                $cache[$title] = ' ' . $text;

            }

        }

        // Update HASH for the new key. Incorporates various administrative keys,

        // including the old HASH (and thereby the EXCESSIVE value from loadFromDB()

        // and previous replace() calls), but that doesn't really matter since we

        // only ever compare it for equality with a copy saved by saveToCaches().

        $cache['HASH'] = md5( serialize( $cache + [ 'EXCESSIVE' => $newBigTitles ] ) );

        // Update the too-big WAN cache entries now that we have the new HASH

        foreach ( $newBigTitles as $title => $id ) {

            // Match logic of loadCachedMessagePageEntry()

            $this->wanCache->set(

                $this->bigMessageCacheKey( $cache['HASH'], $title ),

                ' ' . $newTextByTitle[$title],

                $this->mExpiry

            );

        }

        // Mark this cache as definitely being "latest" (non-volatile) so

        // load() calls do not try to refresh the cache with replica DB data

        $cache['LATEST'] = time();

        // Update the process cache

        $this->cache->set( $code, $cache );

        // Pre-emptively update the local datacenter cache so things like edit filter and

        // blacklist changes are reflected immediately; these often use MediaWiki: pages.

        // The datacenter handling replace() calls should be the same one handling edits

        // as they require HTTP POST.

        $this->saveToCaches( $cache, 'all', $code );

        // Release the lock now that the cache is saved

        ScopedCallback::consume( $scopedLock );


        // Relay the purge. Touching this check key expires cache contents

        // and local cache (APC) validation hash across all datacenters.

        $this->wanCache->touchCheckKey( $this->getCheckKey( $code ) );


        // Purge the messages in the message blob store and fire any hook handlers

        $resourceloader = RequestContext::getMain()->getOutput()->getResourceLoader();

        $blobStore = $resourceloader->getMessageBlobStore();

        foreach ( $replacements as list( $title, $msg ) ) {

            $blobStore->updateMessage( $this->contLang->lcfirst( $msg ) );

            Hooks::run( 'MessageCacheReplace', [ $title, $newTextByTitle[$title] ] );

        }

    }


    protected function isCacheExpired( $cache ) {

        if ( !isset( $cache['VERSION'] ) || !isset( $cache['EXPIRY'] ) ) {

            return true;

        }

        if ( $cache['VERSION'] != MSG_CACHE_VERSION ) {

            return true;

        }

        if ( wfTimestampNow() >= $cache['EXPIRY'] ) {

            return true;

        }


        return false;

    }


    protected function saveToCaches( array $cache, $dest, $code = false ) {

        if ( $dest === 'all' ) {

            $cacheKey = $this->clusterCache->makeKey( 'messages', $code );

            $success = $this->clusterCache->set( $cacheKey, $cache );

            $this->setValidationHash( $code, $cache );

        } else {

            $success = true;

        }


        $this->saveToLocalCache( $code, $cache );


        return $success;

    }


    protected function getValidationHash( $code ) {

        $curTTL = null;

        $value = $this->wanCache->get(

            $this->wanCache->makeKey( 'messages', $code, 'hash', 'v1' ),

            $curTTL,

            [ $this->getCheckKey( $code ) ]

        );


        if ( $value ) {

            $hash = $value['hash'];

            if ( ( time() - $value['latest'] ) < WANObjectCache::TTL_MINUTE ) {

                // Cache was recently updated via replace() and should be up-to-date.

                // That method is only called in the primary datacenter and uses FOR_UPDATE.

                // Also, it is unlikely that the current datacenter is *now* secondary one.

                $expired = false;

            } else {

                // See if the "check" key was bumped after the hash was generated

                $expired = ( $curTTL < 0 );

            }

        } else {

            // No hash found at all; cache must regenerate to be safe

            $hash = false;

            $expired = true;

        }


        return [ $hash, $expired ];

    }


    protected function setValidationHash( $code, array $cache ) {

        $this->wanCache->set(

            $this->wanCache->makeKey( 'messages', $code, 'hash', 'v1' ),

            [

                'hash' => $cache['HASH'],

                'latest' => $cache['LATEST'] ?? 0

            ],

            WANObjectCache::TTL_INDEFINITE

        );

    }


    protected function getReentrantScopedLock( $key, $timeout = self::WAIT_SEC ) {

        return $this->clusterCache->getScopedLock( $key, $timeout, self::LOCK_TTL, __METHOD__ );

    }


    function get( $key, $useDB = true, $langcode = true ) {

        if ( is_int( $key ) ) {

            // Fix numerical strings that somehow become ints

            // on their way here

            $key = (string)$key;

        } elseif ( !is_string( $key ) ) {

            throw new MWException( 'Non-string key given' );

        } elseif ( $key === '' ) {

            // Shortcut: the empty key is always missing

            return false;

        }


        // Normalise title-case input (with some inlining)

        $lckey = self::normalizeKey( $key );


        Hooks::run( 'MessageCache::get', [ &$lckey ] );


        // Loop through each language in the fallback list until we find something useful

        $message = $this->getMessageFromFallbackChain(

            wfGetLangObj( $langcode ),

            $lckey,

            !$this->mDisable && $useDB

        );


        // If we still have no message, maybe the key was in fact a full key so try that

        if ( $message === false ) {

            $parts = explode( '/', $lckey );

            // We may get calls for things that are http-urls from sidebar

            // Let's not load nonexistent languages for those

            // They usually have more than one slash.

            if ( count( $parts ) == 2 && $parts[1] !== '' ) {

                $message = Language::getMessageFor( $parts[0], $parts[1] );

                if ( $message === null ) {

                    $message = false;

                }

            }

        }


        // Post-processing if the message exists

        if ( $message !== false ) {

            // Fix whitespace

            $message = str_replace(

                [

                    # Fix for trailing whitespace, removed by textarea

                    '&#32;',

                    # Fix for NBSP, converted to space by firefox

                    '&nbsp;',

                    '&#160;',

                    '&shy;'

                ],

                [

                    ' ',

                    "\u{00A0}",

                    "\u{00A0}",

                    "\u{00AD}"

                ],

                $message

            );

        }


        return $message;

    }


    protected function getMessageFromFallbackChain( $lang, $lckey, $useDB ) {

        $alreadyTried = [];


        // First try the requested language.

        $message = $this->getMessageForLang( $lang, $lckey, $useDB, $alreadyTried );

        if ( $message !== false ) {

            return $message;

        }


        // Now try checking the site language.

        $message = $this->getMessageForLang( $this->contLang, $lckey, $useDB, $alreadyTried );

        return $message;

    }


    private function getMessageForLang( $lang, $lckey, $useDB, &$alreadyTried ) {

        $langcode = $lang->getCode();


        // Try checking the database for the requested language

        if ( $useDB ) {

            $uckey = $this->contLang->ucfirst( $lckey );


            if ( !isset( $alreadyTried[$langcode] ) ) {

                $message = $this->getMsgFromNamespace(

                    $this->getMessagePageName( $langcode, $uckey ),

                    $langcode

                );

                if ( $message !== false ) {

                    return $message;

                }

                $alreadyTried[$langcode] = true;

            }

        } else {

            $uckey = null;

        }


        // Check the CDB cache

        $message = $lang->getMessage( $lckey );

        if ( $message !== null ) {

            return $message;

        }


        // Try checking the database for all of the fallback languages

        if ( $useDB ) {

            $fallbackChain = Language::getFallbacksFor( $langcode );


            foreach ( $fallbackChain as $code ) {

                if ( isset( $alreadyTried[$code] ) ) {

                    continue;

                }


                $message = $this->getMsgFromNamespace(

                    $this->getMessagePageName( $code, $uckey ), $code );


                if ( $message !== false ) {

                    return $message;

                }

                $alreadyTried[$code] = true;

            }

        }


        return false;

    }


    private function getMessagePageName( $langcode, $uckey ) {

        global $wgLanguageCode;


        if ( $langcode === $wgLanguageCode ) {

            // Messages created in the content language will not have the /lang extension

            return $uckey;

        } else {

            return "$uckey/$langcode";

        }

    }


    public function getMsgFromNamespace( $title, $code ) {

        // Load all MediaWiki page definitions into cache. Note that individual keys

        // already loaded into cache during this request remain in the cache, which

        // includes the value of hook-defined messages.

        $this->load( $code );


        $entry = $this->cache->getField( $code, $title );


        if ( $entry !== null ) {

            // Message page exists as an override of a software messages

            if ( substr( $entry, 0, 1 ) === ' ' ) {

                // The message exists and is not '!TOO BIG'

                return (string)substr( $entry, 1 );

            } elseif ( $entry === '!NONEXISTENT' ) {

                // The text might be '-' or missing due to some data loss

                return false;

            }

            // Load the message page, utilizing the individual message cache.

            // If the page does not exist, there will be no hook handler fallbacks.

            $entry = $this->loadCachedMessagePageEntry(

                $title,

                $code,

                $this->cache->getField( $code, 'HASH' )

            );

        } else {

            // Message page either does not exist or does not override a software message

            $name = $this->contLang->lcfirst( $title );

            if ( !$this->isMainCacheable( $name, $this->overridable ) ) {

                // Message page does not override any software-defined message. A custom

                // message might be defined to have content or settings specific to the wiki.

                // Load the message page, utilizing the individual message cache as needed.

                $entry = $this->loadCachedMessagePageEntry(

                    $title,

                    $code,

                    $this->cache->getField( $code, 'HASH' )

                );

            }

            if ( $entry === null || substr( $entry, 0, 1 ) !== ' ' ) {

                // Message does not have a MediaWiki page definition; try hook handlers

                $message = false;

                Hooks::run( 'MessagesPreLoad', [ $title, &$message, $code ] );

                if ( $message !== false ) {

                    $this->cache->setField( $code, $title, ' ' . $message );

                } else {

                    $this->cache->setField( $code, $title, '!NONEXISTENT' );

                }


                return $message;

            }

        }


        if ( $entry !== false && substr( $entry, 0, 1 ) === ' ' ) {

            if ( $this->cacheVolatile[$code] ) {

                // Make sure that individual keys respect the WAN cache holdoff period too

                LoggerFactory::getInstance( 'MessageCache' )->debug(

                    __METHOD__ . ': loading volatile key \'{titleKey}\'',

                    [ 'titleKey' => $title, 'code' => $code ] );

            } else {

                $this->cache->setField( $code, $title, $entry );

            }

            // The message exists, so make sure a string is returned

            return (string)substr( $entry, 1 );

        }


        $this->cache->setField( $code, $title, '!NONEXISTENT' );


        return false;

    }


    private function loadCachedMessagePageEntry( $dbKey, $code, $hash ) {

        $fname = __METHOD__;

        return $this->srvCache->getWithSetCallback(

            $this->srvCache->makeKey( 'messages-big', $hash, $dbKey ),

            IExpiringStore::TTL_MINUTE,

            function () use ( $code, $dbKey, $hash, $fname ) {

                return $this->wanCache->getWithSetCallback(

                    $this->bigMessageCacheKey( $hash, $dbKey ),

                    $this->mExpiry,

                    function ( $oldValue, &$ttl, &$setOpts ) use ( $dbKey, $code, $fname ) {

                        // Try loading the message from the database

                        $dbr = wfGetDB( DB_REPLICA );

                        $setOpts += Database::getCacheSetOptions( $dbr );

                        // Use newKnownCurrent() to avoid querying revision/user tables

                        $title = Title::makeTitle( NS_MEDIAWIKI, $dbKey );

                        $revision = Revision::newKnownCurrent( $dbr, $title );

                        if ( !$revision ) {

                            // The wiki doesn't have a local override page. Cache absence with normal TTL.

                            // When overrides are created, self::replace() takes care of the cache.

                            return '!NONEXISTENT';

                        }

                        $content = $revision->getContent();

                        if ( $content ) {

                            $message = $this->getMessageTextFromContent( $content );

                        } else {

                            LoggerFactory::getInstance( 'MessageCache' )->warning(

                                $fname . ': failed to load page text for \'{titleKey}\'',

                                [ 'titleKey' => $dbKey, 'code' => $code ]

                            );

                            $message = null;

                        }


                        if ( !is_string( $message ) ) {

                            // Revision failed to load Content, or Content is incompatible with wikitext.

                            // Possibly a temporary loading failure.

                            $ttl = 5;


                            return '!NONEXISTENT';

                        }


                        return ' ' . $message;

                    }

                );

            }

        );

    }


    public function transform( $message, $interface = false, $language = null, $title = null ) {

        // Avoid creating parser if nothing to transform

        if ( strpos( $message, '{{' ) === false ) {

            return $message;

        }


        if ( $this->mInParser ) {

            return $message;

        }


        $parser = $this->getParser();

        if ( $parser ) {

            $popts = $this->getParserOptions();

            $popts->setInterfaceMessage( $interface );

            $popts->setTargetLanguage( $language );


            $userlang = $popts->setUserLang( $language );

            $this->mInParser = true;

            $message = $parser->transformMsg( $message, $popts, $title );

            $this->mInParser = false;

            $popts->setUserLang( $userlang );

        }


        return $message;

    }


    public function getParser() {

        global $wgParser, $wgParserConf;


        if ( !$this->mParser && isset( $wgParser ) ) {

            # Do some initialisation so that we don't have to do it twice

            $wgParser->firstCallInit();

            # Clone it and store it

            $class = $wgParserConf['class'];

            if ( $class == ParserDiffTest::class ) {

                # Uncloneable

                $this->mParser = new $class( $wgParserConf );

            } else {

                $this->mParser = clone $wgParser;

            }

        }


        return $this->mParser;

    }


    public function parse( $text, $title = null, $linestart = true,

        $interface = false, $language = null

    ) {

        global $wgTitle;


        if ( $this->mInParser ) {

            return htmlspecialchars( $text );

        }


        $parser = $this->getParser();

        $popts = $this->getParserOptions();

        $popts->setInterfaceMessage( $interface );


        if ( is_string( $language ) ) {

            $language = Language::factory( $language );

        }

        $popts->setTargetLanguage( $language );


        if ( !$title || !$title instanceof Title ) {

            wfDebugLog( 'GlobalTitleFail', __METHOD__ . ' called by ' .

                wfGetAllCallers( 6 ) . ' with no title set.' );

            $title = $wgTitle;

        }

        // Sometimes $wgTitle isn't set either...

        if ( !$title ) {

            # It's not uncommon having a null $wgTitle in scripts. See r80898

            # Create a ghost title in such case

            $title = Title::makeTitle( NS_SPECIAL, 'Badtitle/title not set in ' . __METHOD__ );

        }


        $this->mInParser = true;

        $res = $parser->parse( $text, $title, $popts, $linestart );

        $this->mInParser = false;


        return $res;

    }


    public function disable() {

        $this->mDisable = true;

    }


    public function enable() {

        $this->mDisable = false;

    }


    public function isDisabled() {

        return $this->mDisable;

    }


    public function clear() {

        $langs = Language::fetchLanguageNames( null, 'mw' );

        foreach ( array_keys( $langs ) as $code ) {

            $this->wanCache->touchCheckKey( $this->getCheckKey( $code ) );

        }

        $this->cache->clear();

        $this->loadedLanguages = [];

    }


    public function figureMessage( $key ) {

        global $wgLanguageCode;


        $pieces = explode( '/', $key );

        if ( count( $pieces ) < 2 ) {

            return [ $key, $wgLanguageCode ];

        }


        $lang = array_pop( $pieces );

        if ( !Language::fetchLanguageName( $lang, null, 'mw' ) ) {

            return [ $key, $wgLanguageCode ];

        }


        $message = implode( '/', $pieces );


        return [ $message, $lang ];

    }


    public function getAllMessageKeys( $code ) {

        $this->load( $code );

        if ( !$this->cache->has( $code ) ) {

            // Apparently load() failed

            return null;

        }

        // Remove administrative keys

        $cache = $this->cache->get( $code );

        unset( $cache['VERSION'] );

        unset( $cache['EXPIRY'] );

        unset( $cache['EXCESSIVE'] );

        // Remove any !NONEXISTENT keys

        $cache = array_diff( $cache, [ '!NONEXISTENT' ] );


        // Keys may appear with a capital first letter. lcfirst them.

        return array_map( [ $this->contLang, 'lcfirst' ], array_keys( $cache ) );

    }


    public function updateMessageOverride( Title $title, Content $content = null ) {

        $msgText = $this->getMessageTextFromContent( $content );

        if ( $msgText === null ) {

            $msgText = false; // treat as not existing

        }


        $this->replace( $title->getDBkey(), $msgText );


        if ( $this->contLang->hasVariants() ) {

            $this->contLang->updateConversionTable( $title );

        }

    }


    public function getCheckKey( $code ) {

        return $this->wanCache->makeKey( 'messages', $code );

    }


    private function getMessageTextFromContent( Content $content = null ) {

        // @TODO: could skip pseudo-messages like js/css here, based on content model

        if ( $content ) {

            // Message page exists...

            // XXX: Is this the right way to turn a Content object into a message?

            // NOTE: $content is typically either WikitextContent, JavaScriptContent or

            //       CssContent. MessageContent is *not* used for storing messages, it's

            //       only used for wrapping them when needed.

            $msgText = $content->getWikitextForTransclusion();

            if ( $msgText === false || $msgText === null ) {

                // This might be due to some kind of misconfiguration...

                $msgText = null;

                LoggerFactory::getInstance( 'MessageCache' )->warning(

                    __METHOD__ . ": message content doesn't provide wikitext "

                    . "(content model: " . $content->getModel() . ")" );

            }

        } else {

            // Message page does not exist...

            $msgText = false;

        }


        return $msgText;

    }


    private function bigMessageCacheKey( $hash, $title ) {

        return $this->wanCache->makeKey( 'messages-big', $hash, $title );

    }


}


or
or
Definition APACHE-LICENSE-2.0.txt:114

use
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
Definition APACHE-LICENSE-2.0.txt:10

by
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for and distribution as defined by Sections through of this document Licensor shall mean the copyright owner or entity authorized by the copyright owner that is granting the License Legal Entity shall mean the union of the acting entity and all other entities that control are controlled by or are under common control with that entity For the purposes of this definition control direct or to cause the direction or management of such whether by contract or including but not limited to software source documentation and configuration files Object form shall mean any form resulting from mechanical transformation or translation of a Source including but not limited to compiled object generated and conversions to other media types Work shall mean the work of whether in Source or Object made available under the as indicated by a copyright notice that is included in or attached to the whether in Source or Object that is based or other modifications as a an original work of authorship For the purposes of this Derivative Works shall not include works that remain separable or merely the Work and Derivative Works thereof Contribution shall mean any work of including the original version of the Work and any modifications or additions to that Work or Derivative Works that is intentionally submitted to Licensor for inclusion in the Work by the copyright owner or by an individual or Legal Entity authorized to submit on behalf of the copyright owner For the purposes of this submitted means any form of or written communication sent to the Licensor or its including but not limited to communication on electronic mailing source code control and issue tracking systems that are managed by
Definition APACHE-LICENSE-2.0.txt:58

serialize
serialize()
Definition ApiMessageTrait.php:131

$wgLanguageCode
$wgLanguageCode
Site language code.
Definition DefaultSettings.php:2942

$wgUseLocalMessageCache
$wgUseLocalMessageCache
Set this to true to maintain a copy of the message cache on the local server.
Definition DefaultSettings.php:2568

$wgAdaptiveMessageCache
$wgAdaptiveMessageCache
Instead of caching everything, only cache those messages which have been customised in the site conte...
Definition DefaultSettings.php:2576

$wgUseDatabaseMessages
$wgUseDatabaseMessages
Translation using MediaWiki: namespace.
Definition DefaultSettings.php:3096

$wgMaxMsgCacheEntrySize
$wgMaxMsgCacheEntrySize
Maximum entry size in the message cache, in bytes.
Definition DefaultSettings.php:3106

$wgParserConf
$wgParserConf
Parser configuration.
Definition DefaultSettings.php:4158

$wgMsgCacheExpiry
$wgMsgCacheExpiry
Expiry time for the message cache key.
Definition DefaultSettings.php:3101

wfGetLangObj
wfGetLangObj( $langcode=false)
Return a Language object from $langcode.
Definition GlobalFunctions.php:1293

wfDebug
wfDebug( $text, $dest='all', array $context=[])
Sends a line to the debug log if enabled or, optionally, to a comment in output.
Definition GlobalFunctions.php:1000

wfTimestampNow
wfTimestampNow()
Convenience function; returns MediaWiki timestamp for the present time.
Definition GlobalFunctions.php:1995

wfGetDB
wfGetDB( $db, $groups=[], $wiki=false)
Get a Database object.
Definition GlobalFunctions.php:2705

wfGetMessageCacheStorage
wfGetMessageCacheStorage()
Get the cache object used by the message cache.
Definition GlobalFunctions.php:3050

wfGetAllCallers
wfGetAllCallers( $limit=3)
Return a string consisting of callers in the stack.
Definition GlobalFunctions.php:1548

wfDebugLog
wfDebugLog( $logGroup, $text, $dest='all', array $context=[])
Send a line to a supplementary debug log file, if configured, or main debug log if not.
Definition GlobalFunctions.php:1094

wfTimestamp
wfTimestamp( $outputtype=TS_UNIX, $ts=0)
Get a timestamp string in one of various formats.
Definition GlobalFunctions.php:1966

MSG_CACHE_VERSION
const MSG_CACHE_VERSION
MediaWiki message cache structure version.
Definition MessageCache.php:32

$success
$success
Definition NoLocalSettings.php:42

$fname
if(defined( 'MW_SETUP_CALLBACK')) $fname
Customization point after all loading (constants, functions, classes, DefaultSettings,...
Definition Setup.php:121

$wgParser
$wgParser
Definition Setup.php:921

$wgTitle
if(! $wgRequest->checkUrlExtension()) if(isset( $_SERVER['PATH_INFO']) && $_SERVER['PATH_INFO'] !='') $wgTitle
Definition api.php:57

BagOStuff
Class representing a cache/ephemeral data store.
Definition BagOStuff.php:58

EmptyBagOStuff
A BagOStuff object with no objects in it.
Definition EmptyBagOStuff.php:29

Language
Internationalisation code.
Definition Language.php:35

MWException
MediaWiki exception.
Definition MWException.php:26

MapCacheLRU
Handles a simple LRU key/value map with a maximum number of entries.
Definition MapCacheLRU.php:37

MediaWiki\Logger\LoggerFactory
PSR-3 logger instance factory.
Definition LoggerFactory.php:45

MediaWiki\MediaWikiServices
MediaWikiServices is the service locator for the application scope of MediaWiki.
Definition MediaWikiServices.php:99

MessageCacheUpdate
Message cache purging and in-place update handler for specific message page changes.
Definition MessageCacheUpdate.php:31

MessageCache
Cache of messages that are defined by MediaWiki namespace pages or by hooks.
Definition MessageCache.php:40

MessageCache\getValidationHash
getValidationHash( $code)
Get the md5 used to validate the local APC cache.
Definition MessageCache.php:767

MessageCache\loadFromDBWithLock
loadFromDBWithLock( $code, array &$where, $mode=null)
Definition MessageCache.php:412

MessageCache\LOCK_TTL
const LOCK_TTL
How long memcached locks last.
Definition MessageCache.php:46

MessageCache\loadFromDB
loadFromDB( $code, $mode=null)
Loads cacheable messages from the database.
Definition MessageCache.php:474

MessageCache\getMessageForLang
getMessageForLang( $lang, $lckey, $useDB, &$alreadyTried)
Given a language, try and fetch messages from that language and its fallbacks.
Definition MessageCache.php:957

MessageCache\$mExpiry
$mExpiry
Lifetime for cache, used by object caching.
Definition MessageCache.php:77

MessageCache\saveToLocalCache
saveToLocalCache( $code, $cache)
Save the cache to APC.
Definition MessageCache.php:238

MessageCache\getMessagePageName
getMessagePageName( $langcode, $uckey)
Get the message page name for a given language.
Definition MessageCache.php:1013

MessageCache\$instance
static $instance
Singleton instance.
Definition MessageCache.php:112

MessageCache\$contLang
Language $contLang
Definition MessageCache.php:99

MessageCache\getCheckKey
getCheckKey( $code)
Definition MessageCache.php:1368

MessageCache\$mParser
Parser $mParser
Definition MessageCache.php:85

MessageCache\saveToCaches
saveToCaches(array $cache, $dest, $code=false)
Shortcut to update caches.
Definition MessageCache.php:747

MessageCache\$mInParser
$mInParser
Definition MessageCache.php:90

MessageCache\refreshAndReplaceInternal
refreshAndReplaceInternal( $code, array $replacements)
Definition MessageCache.php:634

MessageCache\setValidationHash
setValidationHash( $code, array $cache)
Set the md5 used to validate the local disk cache.
Definition MessageCache.php:805

MessageCache\isCacheExpired
isCacheExpired( $cache)
Is the given cache array expired due to time passing or a version change?
Definition MessageCache.php:724

MessageCache\getMsgFromNamespace
getMsgFromNamespace( $title, $code)
Get a message from the MediaWiki namespace, with caching.
Definition MessageCache.php:1036

MessageCache\getReentrantScopedLock
getReentrantScopedLock( $key, $timeout=self::WAIT_SEC)
Definition MessageCache.php:821

MessageCache\WAIT_SEC
const WAIT_SEC
How long to wait for memcached locks.
Definition MessageCache.php:44

MessageCache\$mDisable
$mDisable
Should mean that database cannot be used, but check.
Definition MessageCache.php:71

MessageCache\getLocalCache
getLocalCache( $code)
Try to load the cache from APC.
Definition MessageCache.php:226

MessageCache\destroyInstance
static destroyInstance()
Destroy the singleton instance.
Definition MessageCache.php:144

MessageCache\load
load( $code, $mode=null)
Loads messages from caches or from database in this order: (1) local message cache (if $wgUseLocalMes...
Definition MessageCache.php:264

MessageCache\$srvCache
BagOStuff $srvCache
Definition MessageCache.php:97

MessageCache\transform
transform( $message, $interface=false, $language=null, $title=null)
Definition MessageCache.php:1165

MessageCache\updateMessageOverride
updateMessageOverride(Title $title, Content $content=null)
Purge message caches when a MediaWiki: page is created, updated, or deleted.
Definition MessageCache.php:1351

MessageCache\$loadedLanguages
array $loadedLanguages
Track which languages have been loaded by load().
Definition MessageCache.php:105

MessageCache\getMessageFromFallbackChain
getMessageFromFallbackChain( $lang, $lckey, $useDB)
Given a language, try and fetch messages from that language.
Definition MessageCache.php:933

MessageCache\isDisabled
isDisabled()
Whether DB/cache usage is disabled for determining messages.
Definition MessageCache.php:1278

MessageCache\disable
disable()
Definition MessageCache.php:1258

MessageCache\$clusterCache
BagOStuff $clusterCache
Definition MessageCache.php:95

MessageCache\isMainCacheable
isMainCacheable( $name, array $overridable)
Definition MessageCache.php:588

MessageCache\getParser
getParser()
Definition MessageCache.php:1194

MessageCache\loadCachedMessagePageEntry
loadCachedMessagePageEntry( $dbKey, $code, $hash)
Definition MessageCache.php:1111

MessageCache\getMessageTextFromContent
getMessageTextFromContent(Content $content=null)
Definition MessageCache.php:1376

MessageCache\clear
clear()
Clear all stored messages in global and local cache.
Definition MessageCache.php:1287

MessageCache\singleton
static singleton()
Get the signleton instance of this class.
Definition MessageCache.php:120

MessageCache\getAllMessageKeys
getAllMessageKeys( $code)
Get all message keys stored in the message cache for a given language.
Definition MessageCache.php:1326

MessageCache\$cache
MapCacheLRU $cache
Process cache of loaded messages that are defined in MediaWiki namespace.
Definition MessageCache.php:53

MessageCache\$wanCache
WANObjectCache $wanCache
Definition MessageCache.php:93

MessageCache\normalizeKey
static normalizeKey( $key)
Normalize message key input.
Definition MessageCache.php:154

MessageCache\FOR_UPDATE
const FOR_UPDATE
Definition MessageCache.php:41

MessageCache\enable
enable()
Definition MessageCache.php:1262

MessageCache\figureMessage
figureMessage( $key)
Definition MessageCache.php:1300

MessageCache\$cacheVolatile
bool[] $cacheVolatile
Map of (language code => boolean)
Definition MessageCache.php:65

MessageCache\parse
parse( $text, $title=null, $linestart=true, $interface=false, $language=null)
Definition MessageCache.php:1221

MessageCache\$mParserOptions
ParserOptions $mParserOptions
Message cache has its own parser which it uses to transform messages.
Definition MessageCache.php:83

MessageCache\replace
replace( $title, $text)
Updates cache as necessary when message page is changed.
Definition MessageCache.php:600

MessageCache\__construct
__construct(WANObjectCache $wanCache, BagOStuff $clusterCache, BagOStuff $serverCache, $useDB, $expiry, Language $contLang=null)
Definition MessageCache.php:173

MessageCache\getParserOptions
getParserOptions()
ParserOptions is lazy initialised.
Definition MessageCache.php:197

MessageCache\bigMessageCacheKey
bigMessageCacheKey( $hash, $title)
Definition MessageCache.php:1405

MessageCache\$overridable
array $overridable
Map of (lowercase message key => index) for all software defined messages.
Definition MessageCache.php:60

ParserOptions
Set options of the Parser.
Definition ParserOptions.php:42

ParserOptions\setAllowUnsafeRawHtml
setAllowUnsafeRawHtml( $x)
If the wiki is configured to allow raw html ($wgRawHtml = true) is it allowed in the specific case of...
Definition ParserOptions.php:769

Parser
PHP Parser - Processes wiki markup (which uses a more user-friendly syntax, such as "[[link]]" for ma...
Definition Parser.php:68

Revision\newKnownCurrent
static newKnownCurrent(IDatabase $db, $pageIdOrTitle, $revId=0)
Load a revision based on a known page ID and current revision ID from the DB.
Definition Revision.php:1299

Revision\getRevisionText
static getRevisionText( $row, $prefix='old_', $wiki=false)
Get revision text associated with an old or archive row.
Definition Revision.php:1050

Title
Represents a title within MediaWiki.
Definition Title.php:39

Title\getDBkey
getDBkey()
Get the main part with underscores.
Definition Title.php:951

WANObjectCache
Multi-datacenter aware caching interface.
Definition WANObjectCache.php:118

Wikimedia\Rdbms\Database
Relational database abstraction object.
Definition Database.php:48

$res
$res
Definition database.txt:21

list
deferred txt A few of the database updates required by various functions here can be deferred until after the result page is displayed to the user For updating the view updating the linked to tables after a etc PHP does not yet have any way to tell the server to actually return and disconnect while still running these but it might have such a feature in the future We handle these by creating a deferred update object and putting those objects on a global list
Definition deferred.txt:11

as
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such as
Definition distributors.txt:22

too
This document is intended to provide useful advice for parties seeking to redistribute MediaWiki to end users It s targeted particularly at maintainers for Linux since it s been observed that distribution packages of MediaWiki often break We ve consistently had to recommend that users seeking support use official tarballs instead of their distribution s and this often solves whatever problem the user is having It would be nice if this could such and we might be restricted by PHP settings such as safe mode or open_basedir We cannot assume that the software even has read access anywhere useful Many shared hosts run all users web applications under the same so they can t rely on Unix and must forbid reads to even standard directories like tmp lest users read each others files We cannot assume that the user has the ability to install or run any programs not written as web accessible PHP scripts Since anything that works on cheap shared hosting will work if you have shell or root access too
Definition distributors.txt:32

of
globals txt Globals are evil The original MediaWiki code relied on globals for processing context far too often MediaWiki development since then has been a story of slowly moving context out of global variables and into objects Storing processing context in object member variables allows those objects to be reused in a much more flexible way Consider the elegance of
database rows
Definition globals.txt:10

NS_MEDIAWIKI
const NS_MEDIAWIKI
Definition Defines.php:72

NS_SPECIAL
const NS_SPECIAL
Definition Defines.php:53

$parser
see documentation in includes Linker php for Linker::makeImageLink or false for current used if you return false $parser
Definition hooks.txt:1873

replace
static configuration should be added through ResourceLoaderGetConfigVars instead can be used to get the real title e g db for database replication lag or jobqueue for job queue size converted to pseudo seconds It is possible to add more fields and they will be returned to the user in the API response after the basic globals have been set but before ordinary actions take place replace
Definition hooks.txt:2317

string
This code would result in ircNotify being run twice when an article is and once for brion Hooks can return three possible true was required This is the default since MediaWiki *some string
Definition hooks.txt:181

$status
Status::newGood()` to allow deletion, and then `return false` from the hook function. Ensure you consume the 'ChangeTagAfterDelete' hook to carry out custom deletion actions. $tag:name of the tag $user:user initiating the action & $status:Status object. See above. 'ChangeTagsListActive':Allows you to nominate which of the tags your extension uses are in active use. & $tags:list of all active tags. Append to this array. 'ChangeTagsAfterUpdateTags':Called after tags have been updated with the ChangeTags::updateTags function. Params:$addedTags:tags effectively added in the update $removedTags:tags effectively removed in the update $prevTags:tags that were present prior to the update $rc_id:recentchanges table id $rev_id:revision table id $log_id:logging table id $params:tag params $rc:RecentChange being tagged when the tagging accompanies the action, or null $user:User who performed the tagging when the tagging is subsequent to the action, or null 'ChangeTagsAllowedAdd':Called when checking if a user can add tags to a change. & $allowedTags:List of all the tags the user is allowed to add. Any tags the user wants to add( $addTags) that are not in this array will cause it to fail. You may add or remove tags to this array as required. $addTags:List of tags user intends to add. $user:User who is adding the tags. 'ChangeUserGroups':Called before user groups are changed. $performer:The User who will perform the change $user:The User whose groups will be changed & $add:The groups that will be added & $remove:The groups that will be removed 'Collation::factory':Called if $wgCategoryCollation is an unknown collation. $collationName:Name of the collation in question & $collationObject:Null. Replace with a subclass of the Collation class that implements the collation given in $collationName. 'ConfirmEmailComplete':Called after a user 's email has been confirmed successfully. $user:user(object) whose email is being confirmed 'ContentAlterParserOutput':Modify parser output for a given content object. Called by Content::getParserOutput after parsing has finished. Can be used for changes that depend on the result of the parsing but have to be done before LinksUpdate is called(such as adding tracking categories based on the rendered HTML). $content:The Content to render $title:Title of the page, as context $parserOutput:ParserOutput to manipulate 'ContentGetParserOutput':Customize parser output for a given content object, called by AbstractContent::getParserOutput. May be used to override the normal model-specific rendering of page content. $content:The Content to render $title:Title of the page, as context $revId:The revision ID, as context $options:ParserOptions for rendering. To avoid confusing the parser cache, the output can only depend on parameters provided to this hook function, not on global state. $generateHtml:boolean, indicating whether full HTML should be generated. If false, generation of HTML may be skipped, but other information should still be present in the ParserOutput object. & $output:ParserOutput, to manipulate or replace 'ContentHandlerDefaultModelFor':Called when the default content model is determined for a given title. May be used to assign a different model for that title. $title:the Title in question & $model:the model name. Use with CONTENT_MODEL_XXX constants. 'ContentHandlerForModelID':Called when a ContentHandler is requested for a given content model name, but no entry for that model exists in $wgContentHandlers. Note:if your extension implements additional models via this hook, please use GetContentModels hook to make them known to core. $modeName:the requested content model name & $handler:set this to a ContentHandler object, if desired. 'ContentModelCanBeUsedOn':Called to determine whether that content model can be used on a given page. This is especially useful to prevent some content models to be used in some special location. $contentModel:ID of the content model in question $title:the Title in question. & $ok:Output parameter, whether it is OK to use $contentModel on $title. Handler functions that modify $ok should generally return false to prevent further hooks from further modifying $ok. 'ContribsPager::getQueryInfo':Before the contributions query is about to run & $pager:Pager object for contributions & $queryInfo:The query for the contribs Pager 'ContribsPager::reallyDoQuery':Called before really executing the query for My Contributions & $data:an array of results of all contribs queries $pager:The ContribsPager object hooked into $offset:Index offset, inclusive $limit:Exact query limit $descending:Query direction, false for ascending, true for descending 'ContributionsLineEnding':Called before a contributions HTML line is finished $page:SpecialPage object for contributions & $ret:the HTML line $row:the DB row for this line & $classes:the classes to add to the surrounding< li > & $attribs:associative array of other HTML attributes for the< li > element. Currently only data attributes reserved to MediaWiki are allowed(see Sanitizer::isReservedDataAttribute). 'ContributionsToolLinks':Change tool links above Special:Contributions $id:User identifier $title:User page title & $tools:Array of tool links $specialPage:SpecialPage instance for context and services. Can be either SpecialContributions or DeletedContributionsPage. Extensions should type hint against a generic SpecialPage though. 'ConvertContent':Called by AbstractContent::convert when a conversion to another content model is requested. Handler functions that modify $result should generally return false to disable further attempts at conversion. $content:The Content object to be converted. $toModel:The ID of the content model to convert to. $lossy:boolean indicating whether lossy conversion is allowed. & $result:Output parameter, in case the handler function wants to provide a converted Content object. Note that $result->getContentModel() must return $toModel. 'ContentSecurityPolicyDefaultSource':Modify the allowed CSP load sources. This affects all directives except for the script directive. If you want to add a script source, see ContentSecurityPolicyScriptSource hook. & $defaultSrc:Array of Content-Security-Policy allowed sources $policyConfig:Current configuration for the Content-Security-Policy header $mode:ContentSecurityPolicy::REPORT_ONLY_MODE or ContentSecurityPolicy::FULL_MODE depending on type of header 'ContentSecurityPolicyDirectives':Modify the content security policy directives. Use this only if ContentSecurityPolicyDefaultSource and ContentSecurityPolicyScriptSource do not meet your needs. & $directives:Array of CSP directives $policyConfig:Current configuration for the CSP header $mode:ContentSecurityPolicy::REPORT_ONLY_MODE or ContentSecurityPolicy::FULL_MODE depending on type of header 'ContentSecurityPolicyScriptSource':Modify the allowed CSP script sources. Note that you also have to use ContentSecurityPolicyDefaultSource if you want non-script sources to be loaded from whatever you add. & $scriptSrc:Array of CSP directives $policyConfig:Current configuration for the CSP header $mode:ContentSecurityPolicy::REPORT_ONLY_MODE or ContentSecurityPolicy::FULL_MODE depending on type of header 'CustomEditor':When invoking the page editor Return true to allow the normal editor to be used, or false if implementing a custom editor, e.g. for a special namespace, etc. $article:Article being edited $user:User performing the edit 'DatabaseOraclePostInit':Called after initialising an Oracle database $db:the DatabaseOracle object 'DeletedContribsPager::reallyDoQuery':Called before really executing the query for Special:DeletedContributions Similar to ContribsPager::reallyDoQuery & $data:an array of results of all contribs queries $pager:The DeletedContribsPager object hooked into $offset:Index offset, inclusive $limit:Exact query limit $descending:Query direction, false for ascending, true for descending 'DeletedContributionsLineEnding':Called before a DeletedContributions HTML line is finished. Similar to ContributionsLineEnding $page:SpecialPage object for DeletedContributions & $ret:the HTML line $row:the DB row for this line & $classes:the classes to add to the surrounding< li > & $attribs:associative array of other HTML attributes for the< li > element. Currently only data attributes reserved to MediaWiki are allowed(see Sanitizer::isReservedDataAttribute). 'DeleteUnknownPreferences':Called by the cleanupPreferences.php maintenance script to build a WHERE clause with which to delete preferences that are not known about. This hook is used by extensions that have dynamically-named preferences that should not be deleted in the usual cleanup process. For example, the Gadgets extension creates preferences prefixed with 'gadget-', and so anything with that prefix is excluded from the deletion. &where:An array that will be passed as the $cond parameter to IDatabase::select() to determine what will be deleted from the user_properties table. $db:The IDatabase object, useful for accessing $db->buildLike() etc. 'DifferenceEngineAfterLoadNewText':called in DifferenceEngine::loadNewText() after the new revision 's content has been loaded into the class member variable $differenceEngine->mNewContent but before returning true from this function. $differenceEngine:DifferenceEngine object 'DifferenceEngineLoadTextAfterNewContentIsLoaded':called in DifferenceEngine::loadText() after the new revision 's content has been loaded into the class member variable $differenceEngine->mNewContent but before checking if the variable 's value is null. This hook can be used to inject content into said class member variable. $differenceEngine:DifferenceEngine object 'DifferenceEngineMarkPatrolledLink':Allows extensions to change the "mark as patrolled" link which is shown both on the diff header as well as on the bottom of a page, usually wrapped in a span element which has class="patrollink". $differenceEngine:DifferenceEngine object & $markAsPatrolledLink:The "mark as patrolled" link HTML(string) $rcid:Recent change ID(rc_id) for this change(int) 'DifferenceEngineMarkPatrolledRCID':Allows extensions to possibly change the rcid parameter. For example the rcid might be set to zero due to the user being the same as the performer of the change but an extension might still want to show it under certain conditions. & $rcid:rc_id(int) of the change or 0 $differenceEngine:DifferenceEngine object $change:RecentChange object $user:User object representing the current user 'DifferenceEngineNewHeader':Allows extensions to change the $newHeader variable, which contains information about the new revision, such as the revision 's author, whether the revision was marked as a minor edit or not, etc. $differenceEngine:DifferenceEngine object & $newHeader:The string containing the various #mw-diff-otitle[1-5] divs, which include things like revision author info, revision comment, RevisionDelete link and more $formattedRevisionTools:Array containing revision tools, some of which may have been injected with the DiffRevisionTools hook $nextlink:String containing the link to the next revision(if any) $status
Definition hooks.txt:1305

$title
namespace and then decline to actually register it file or subcat img or subcat $title
Definition hooks.txt:994

$code
this hook is for auditing only or null if authentication failed before getting that far or null if we can t even determine that probably a stub it is not rendered in wiki pages or galleries in category pages allow injecting custom HTML after the section Any uses of the hook need to handle escaping see BaseTemplate::getToolbox and BaseTemplate::makeListItem for details on the format of individual items inside of this array or by returning and letting standard HTTP rendering take place modifiable or by returning false and taking over the output modifiable & $code
Definition hooks.txt:895

true
null means default in associative array with keys and values unescaped Should be merged with default with a value of false meaning to suppress the attribute in associative array with keys and values unescaped noclasses just before the function returns a value If you return true
Definition hooks.txt:2055

$services
static configuration should be added through ResourceLoaderGetConfigVars instead can be used to get the real title e g db for database replication lag or jobqueue for job queue size converted to pseudo seconds It is possible to add more fields and they will be returned to the user in the API response after the basic globals have been set but before ordinary actions take place or wrap services the preferred way to define a new service is the $wgServiceWiringFiles array $services
Definition hooks.txt:2335

$name
Allows to change the fields on the form that will be generated $name
Definition hooks.txt:302

function
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback function
Definition injection.txt:30

php
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition injection.txt:37

Content
Base interface for content objects.
Definition Content.php:34

cache
you have access to all of the normal MediaWiki so you can get a DB use the cache
Definition maintenance.txt:55

$cache
$cache
Definition mcc.php:33

array
The wiki should then use memcached to cache various data To use multiple just add more items to the array To increase the weight of a make its entry a array("192.168.0.1:11211", 2))

load
MediaWiki has optional support for a high distributed memory object caching system For general information on but for a larger site with heavy load
Definition memcached.txt:6

$content
$content
Definition pageupdater.txt:72

data
This document describes the state of Postgres support in and is fairly well maintained The main code is very well while extensions are very hit and miss it is probably the most supported database after MySQL Much of the work in making MediaWiki database agnostic came about through the work of creating Postgres as and are nearing end of but without copying over all the usage comments General notes on the but these can almost always be programmed around *Although Postgres has a true BOOLEAN boolean columns are always mapped to as the code does not always treat the column as a and VARBINARY columns should simply be TEXT The only exception is when VARBINARY is used to store true binary data
Definition postgres.txt:43

DB_REPLICA
const DB_REPLICA
Definition defines.php:25

DB_MASTER
const DB_MASTER
Definition defines.php:26

$value
$value
Definition styleTest.css.php:49

$lang
if(!isset( $args[0])) $lang
Definition testCompression.php:33

$dbr
$dbr
Definition testCompression.php:50