- public static function parseAndStash( WikiPage $page, Content $content, User $user, $summary ) {
- $logger = LoggerFactory::getInstance( 'StashEdit' );
-
- $title = $page->getTitle();
- $key = self::getStashKey( $title, self::getContentHash( $content ), $user );
- $fname = __METHOD__;
-
- // Use the master DB to allow for fast blocking locks on the "save path" where this
- // value might actually be used to complete a page edit. If the edit submission request
- // happens before this edit stash requests finishes, then the submission will block until
- // the stash request finishes parsing. For the lock acquisition below, there is not much
- // need to duplicate parsing of the same content/user/summary bundle, so try to avoid
- // blocking at all here.
- $dbw = wfGetDB( DB_MASTER );
- if ( !$dbw->lock( $key, $fname, 0 ) ) {
- // De-duplicate requests on the same key
- return self::ERROR_BUSY;
- }
- /** @noinspection PhpUnusedLocalVariableInspection */
- $unlocker = new ScopedCallback( function () use ( $dbw, $key, $fname ) {
- $dbw->unlock( $key, $fname );
- } );
-
- $cutoffTime = time() - self::PRESUME_FRESH_TTL_SEC;
-
- // Reuse any freshly build matching edit stash cache
- $editInfo = self::getStashValue( $key );
- if ( $editInfo && wfTimestamp( TS_UNIX, $editInfo->timestamp ) >= $cutoffTime ) {
- $alreadyCached = true;
- } else {
- $format = $content->getDefaultFormat();
- $editInfo = $page->prepareContentForEdit( $content, null, $user, $format, false );
- $alreadyCached = false;
- }
-
- if ( $editInfo && $editInfo->output ) {
- // Let extensions add ParserOutput metadata or warm other caches
- Hooks::run( 'ParserOutputStashForEdit',
- [ $page, $content, $editInfo->output, $summary, $user ] );
-
- $titleStr = (string)$title;
- if ( $alreadyCached ) {
- $logger->debug( "Already cached parser output for key '{cachekey}' ('{title}').",
- [ 'cachekey' => $key, 'title' => $titleStr ] );
- return self::ERROR_NONE;
- }
-
- $code = self::storeStashValue(
- $key,
- $editInfo->pstContent,
- $editInfo->output,
- $editInfo->timestamp,
- $user
- );
-
- if ( $code === true ) {
- $logger->debug( "Cached parser output for key '{cachekey}' ('{title}').",
- [ 'cachekey' => $key, 'title' => $titleStr ] );
- return self::ERROR_NONE;
- } elseif ( $code === 'uncacheable' ) {
- $logger->info(
- "Uncacheable parser output for key '{cachekey}' ('{title}') [{code}].",
- [ 'cachekey' => $key, 'title' => $titleStr, 'code' => $code ] );
- return self::ERROR_UNCACHEABLE;
- } else {
- $logger->error( "Failed to cache parser output for key '{cachekey}' ('{title}').",
- [ 'cachekey' => $key, 'title' => $titleStr, 'code' => $code ] );
- return self::ERROR_CACHE;
- }
- }
-
- return self::ERROR_PARSE;
- }
-
- /**
- * Check that a prepared edit is in cache and still up-to-date
- *
- * This method blocks if the prepared edit is already being rendered,
- * waiting until rendering finishes before doing final validity checks.
- *
- * The cache is rejected if template or file changes are detected.
- * Note that foreign template or file transclusions are not checked.
- *
- * The result is a map (pstContent,output,timestamp) with fields
- * extracted directly from WikiPage::prepareContentForEdit().
- *
- * @param Title $title
- * @param Content $content
- * @param User $user User to get parser options from
- * @return stdClass|bool Returns false on cache miss
- */
- public static function checkCache( Title $title, Content $content, User $user ) {
- if ( $user->isBot() ) {
- return false; // bots never stash - don't pollute stats
- }
-
- $logger = LoggerFactory::getInstance( 'StashEdit' );
- $stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
-
- $key = self::getStashKey( $title, self::getContentHash( $content ), $user );
- $editInfo = self::getStashValue( $key );
- if ( !is_object( $editInfo ) ) {
- $start = microtime( true );
- // We ignore user aborts and keep parsing. Block on any prior parsing
- // so as to use its results and make use of the time spent parsing.
- // Skip this logic if there no master connection in case this method
- // is called on an HTTP GET request for some reason.
- $lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
- $dbw = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
- if ( $dbw && $dbw->lock( $key, __METHOD__, 30 ) ) {
- $editInfo = self::getStashValue( $key );
- $dbw->unlock( $key, __METHOD__ );
- }
-
- $timeMs = 1000 * max( 0, microtime( true ) - $start );
- $stats->timing( 'editstash.lock_wait_time', $timeMs );
- }
-
- if ( !is_object( $editInfo ) || !$editInfo->output ) {
- $stats->increment( 'editstash.cache_misses.no_stash' );
- $logger->debug( "Empty cache for key '$key' ('$title'); user '{$user->getName()}'." );
- return false;
- }
-
- $age = time() - wfTimestamp( TS_UNIX, $editInfo->output->getCacheTime() );
- if ( $age <= self::PRESUME_FRESH_TTL_SEC ) {
- // Assume nothing changed in this time
- $stats->increment( 'editstash.cache_hits.presumed_fresh' );
- $logger->debug( "Timestamp-based cache hit for key '$key' (age: $age sec)." );
- } elseif ( isset( $editInfo->edits ) && $editInfo->edits === $user->getEditCount() ) {
- // Logged-in user made no local upload/template edits in the meantime
- $stats->increment( 'editstash.cache_hits.presumed_fresh' );
- $logger->debug( "Edit count based cache hit for key '$key' (age: $age sec)." );
- } elseif ( $user->isAnon()
- && self::lastEditTime( $user ) < $editInfo->output->getCacheTime()
- ) {
- // Logged-out user made no local upload/template edits in the meantime
- $stats->increment( 'editstash.cache_hits.presumed_fresh' );
- $logger->debug( "Edit check based cache hit for key '$key' (age: $age sec)." );
- } else {
- // User may have changed included content
- $editInfo = false;
- }
-
- if ( !$editInfo ) {
- $stats->increment( 'editstash.cache_misses.proven_stale' );
- $logger->info( "Stale cache for key '$key'; old key with outside edits. (age: $age sec)" );
- } elseif ( $editInfo->output->getFlag( 'vary-revision' ) ) {
- // This can be used for the initial parse, e.g. for filters or doEditContent(),
- // but a second parse will be triggered in doEditUpdates(). This is not optimal.
- $logger->info( "Cache for key '$key' ('$title') has vary_revision." );
- } elseif ( $editInfo->output->getFlag( 'vary-revision-id' ) ) {
- // Similar to the above if we didn't guess the ID correctly.
- $logger->info( "Cache for key '$key' ('$title') has vary_revision_id." );
- }
-
- return $editInfo;
- }
-
- /**
- * @param User $user
- * @return string|null TS_MW timestamp or null
- */
- private static function lastEditTime( User $user ) {
- $db = wfGetDB( DB_REPLICA );
- $actorQuery = ActorMigration::newMigration()->getWhere( $db, 'rc_user', $user, false );
- $time = $db->selectField(
- [ 'recentchanges' ] + $actorQuery['tables'],
- 'MAX(rc_timestamp)',
- [ $actorQuery['conds'] ],
- __METHOD__,
- [],
- $actorQuery['joins']
- );
-
- return wfTimestampOrNull( TS_MW, $time );
- }
-
- /**
- * Get hash of the content, factoring in model/format
- *
- * @param Content $content
- * @return string
- */
- private static function getContentHash( Content $content ) {
- return sha1( implode( "\n", [
- $content->getModel(),
- $content->getDefaultFormat(),
- $content->serialize( $content->getDefaultFormat() )
- ] ) );
- }
-
- /**
- * Get the temporary prepared edit stash key for a user
- *
- * This key can be used for caching prepared edits provided:
- * - a) The $user was used for PST options
- * - b) The parser output was made from the PST using cannonical matching options
- *
- * @param Title $title
- * @param string $contentHash Result of getContentHash()
- * @param User $user User to get parser options from
- * @return string
- */
- private static function getStashKey( Title $title, $contentHash, User $user ) {
- return ObjectCache::getLocalClusterInstance()->makeKey(
- 'stashed-edit-info',
- md5( $title->getPrefixedDBkey() ),
- // Account for the edit model/text
- $contentHash,
- // Account for user name related variables like signatures
- md5( $user->getId() . "\n" . $user->getName() )
- );
- }
-
- /**
- * @param string $uuid
- * @return string
- */
- private static function getStashParserOutputKey( $uuid ) {
- return ObjectCache::getLocalClusterInstance()->makeKey( 'stashed-edit-output', $uuid );
- }
-
- /**
- * @param string $key
- * @return stdClass|bool Object map (pstContent,output,outputID,timestamp,edits) or false
- */
- private static function getStashValue( $key ) {
- $cache = ObjectCache::getLocalClusterInstance();
-
- $stashInfo = $cache->get( $key );
- if ( !is_object( $stashInfo ) ) {
- return false;
- }
-
- $parserOutputKey = self::getStashParserOutputKey( $stashInfo->outputID );
- $parserOutput = $cache->get( $parserOutputKey );
- if ( $parserOutput instanceof ParserOutput ) {
- $stashInfo->output = $parserOutput;
-
- return $stashInfo;
- }
-
- return false;
- }
-
- /**
- * Build a value to store in memcached based on the PST content and parser output
- *
- * This makes a simple version of WikiPage::prepareContentForEdit() as stash info
- *
- * @param string $key
- * @param Content $pstContent Pre-Save transformed content
- * @param ParserOutput $parserOutput
- * @param string $timestamp TS_MW
- * @param User $user
- * @return string|bool True or an error code
- */
- private static function storeStashValue(
- $key, Content $pstContent, ParserOutput $parserOutput, $timestamp, User $user
- ) {
- // If an item is renewed, mind the cache TTL determined by config and parser functions.
- // Put an upper limit on the TTL for sanity to avoid extreme template/file staleness.
- $age = time() - wfTimestamp( TS_UNIX, $parserOutput->getCacheTime() );
- $ttl = min( $parserOutput->getCacheExpiry() - $age, self::MAX_CACHE_TTL );
- // Avoid extremely stale user signature timestamps (T84843)
- if ( $parserOutput->getFlag( 'user-signature' ) ) {
- $ttl = min( $ttl, self::MAX_SIGNATURE_TTL );
- }
-
- if ( $ttl <= 0 ) {
- return 'uncacheable'; // low TTL due to a tag, magic word, or signature?
- }
-
- // Store what is actually needed and split the output into another key (T204742)
- $parseroutputID = md5( $key );
- $stashInfo = (object)[
- 'pstContent' => $pstContent,
- 'outputID' => $parseroutputID,
- 'timestamp' => $timestamp,
- 'edits' => $user->getEditCount()
- ];
-
- $cache = ObjectCache::getLocalClusterInstance();
- $ok = $cache->set( $key, $stashInfo, $ttl );
- if ( $ok ) {
- $ok = $cache->set(
- self::getStashParserOutputKey( $parseroutputID ),
- $parserOutput,
- $ttl
- );
- }
-
- if ( $ok ) {
- // These blobs can waste slots in low cardinality memcached slabs
- self::pruneExcessStashedEntries( $cache, $user, $key );
- }
-
- return $ok ? true : 'store_error';
- }
-
- /**
- * @param BagOStuff $cache
- * @param User $user
- * @param string $newKey
- */
- private static function pruneExcessStashedEntries( BagOStuff $cache, User $user, $newKey ) {
- $key = $cache->makeKey( 'stash-edit-recent', $user->getId() );
-
- $keyList = $cache->get( $key ) ?: [];
- if ( count( $keyList ) >= self::MAX_CACHE_RECENT ) {
- $oldestKey = array_shift( $keyList );
- $cache->delete( $oldestKey );
- }