482 lines
16 KiB
PHP
482 lines
16 KiB
PHP
<?php
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/**
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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*/
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use MediaWiki\Logger\LoggerFactory;
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use MediaWiki\MediaWikiServices;
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use Wikimedia\ScopedCallback;
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/**
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* Prepare an edit in shared cache so that it can be reused on edit
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*
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* This endpoint can be called via AJAX as the user focuses on the edit
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* summary box. By the time of submission, the parse may have already
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* finished, and can be immediately used on page save. Certain parser
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* functions like {{REVISIONID}} or {{CURRENTTIME}} may cause the cache
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* to not be used on edit. Template and files used are check for changes
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* since the output was generated. The cache TTL is also kept low for sanity.
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*
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* @ingroup API
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* @since 1.25
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*/
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class ApiStashEdit extends ApiBase {
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const ERROR_NONE = 'stashed';
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const ERROR_PARSE = 'error_parse';
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const ERROR_CACHE = 'error_cache';
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const ERROR_UNCACHEABLE = 'uncacheable';
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const ERROR_BUSY = 'busy';
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const PRESUME_FRESH_TTL_SEC = 30;
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const MAX_CACHE_TTL = 300; // 5 minutes
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const MAX_SIGNATURE_TTL = 60;
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public function execute() {
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$user = $this->getUser();
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$params = $this->extractRequestParams();
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if ( $user->isBot() ) { // sanity
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$this->dieWithError( 'apierror-botsnotsupported' );
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}
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$cache = ObjectCache::getLocalClusterInstance();
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$page = $this->getTitleOrPageId( $params );
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$title = $page->getTitle();
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if ( !ContentHandler::getForModelID( $params['contentmodel'] )
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->isSupportedFormat( $params['contentformat'] )
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) {
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$this->dieWithError(
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[ 'apierror-badformat-generic', $params['contentformat'], $params['contentmodel'] ],
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'badmodelformat'
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);
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}
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$this->requireAtLeastOneParameter( $params, 'stashedtexthash', 'text' );
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$text = null;
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$textHash = null;
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if ( strlen( $params['stashedtexthash'] ) ) {
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// Load from cache since the client indicates the text is the same as last stash
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$textHash = $params['stashedtexthash'];
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if ( !preg_match( '/^[0-9a-f]{40}$/', $textHash ) ) {
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$this->dieWithError( 'apierror-stashedit-missingtext', 'missingtext' );
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}
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$textKey = $cache->makeKey( 'stashedit', 'text', $textHash );
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$text = $cache->get( $textKey );
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if ( !is_string( $text ) ) {
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$this->dieWithError( 'apierror-stashedit-missingtext', 'missingtext' );
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}
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} elseif ( $params['text'] !== null ) {
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// Trim and fix newlines so the key SHA1's match (see WebRequest::getText())
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$text = rtrim( str_replace( "\r\n", "\n", $params['text'] ) );
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$textHash = sha1( $text );
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} else {
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$this->dieWithError( [
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'apierror-missingparam-at-least-one-of',
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Message::listParam( [ '<var>stashedtexthash</var>', '<var>text</var>' ] ),
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2,
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], 'missingparam' );
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}
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$textContent = ContentHandler::makeContent(
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$text, $title, $params['contentmodel'], $params['contentformat'] );
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$page = WikiPage::factory( $title );
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if ( $page->exists() ) {
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// Page exists: get the merged content with the proposed change
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$baseRev = Revision::newFromPageId( $page->getId(), $params['baserevid'] );
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if ( !$baseRev ) {
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$this->dieWithError( [ 'apierror-nosuchrevid', $params['baserevid'] ] );
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}
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$currentRev = $page->getRevision();
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if ( !$currentRev ) {
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$this->dieWithError( [ 'apierror-missingrev-pageid', $page->getId() ], 'missingrev' );
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}
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// Merge in the new version of the section to get the proposed version
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$editContent = $page->replaceSectionAtRev(
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$params['section'],
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$textContent,
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$params['sectiontitle'],
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$baseRev->getId()
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);
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if ( !$editContent ) {
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$this->dieWithError( 'apierror-sectionreplacefailed', 'replacefailed' );
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}
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if ( $currentRev->getId() == $baseRev->getId() ) {
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// Base revision was still the latest; nothing to merge
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$content = $editContent;
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} else {
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// Merge the edit into the current version
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$baseContent = $baseRev->getContent();
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$currentContent = $currentRev->getContent();
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if ( !$baseContent || !$currentContent ) {
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$this->dieWithError( [ 'apierror-missingcontent-pageid', $page->getId() ], 'missingrev' );
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}
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$handler = ContentHandler::getForModelID( $baseContent->getModel() );
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$content = $handler->merge3( $baseContent, $editContent, $currentContent );
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}
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} else {
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// New pages: use the user-provided content model
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$content = $textContent;
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}
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if ( !$content ) { // merge3() failed
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$this->getResult()->addValue( null,
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$this->getModuleName(), [ 'status' => 'editconflict' ] );
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return;
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}
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// The user will abort the AJAX request by pressing "save", so ignore that
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ignore_user_abort( true );
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if ( $user->pingLimiter( 'stashedit' ) ) {
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$status = 'ratelimited';
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} else {
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$status = self::parseAndStash( $page, $content, $user, $params['summary'] );
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$textKey = $cache->makeKey( 'stashedit', 'text', $textHash );
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$cache->set( $textKey, $text, self::MAX_CACHE_TTL );
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}
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$stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
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$stats->increment( "editstash.cache_stores.$status" );
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$this->getResult()->addValue(
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null,
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$this->getModuleName(),
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[
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'status' => $status,
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'texthash' => $textHash
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]
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);
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}
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/**
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* @param WikiPage $page
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* @param Content $content Edit content
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* @param User $user
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* @param string $summary Edit summary
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* @return string ApiStashEdit::ERROR_* constant
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* @since 1.25
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*/
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public static function parseAndStash( WikiPage $page, Content $content, User $user, $summary ) {
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$cache = ObjectCache::getLocalClusterInstance();
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$logger = LoggerFactory::getInstance( 'StashEdit' );
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$title = $page->getTitle();
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$key = self::getStashKey( $title, self::getContentHash( $content ), $user );
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// Use the master DB to allow for fast blocking locks on the "save path" where this
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// value might actually be used to complete a page edit. If the edit submission request
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// happens before this edit stash requests finishes, then the submission will block until
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// the stash request finishes parsing. For the lock acquisition below, there is not much
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// need to duplicate parsing of the same content/user/summary bundle, so try to avoid
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// blocking at all here.
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$dbw = wfGetDB( DB_MASTER );
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if ( !$dbw->lock( $key, __METHOD__, 0 ) ) {
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// De-duplicate requests on the same key
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return self::ERROR_BUSY;
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}
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/** @noinspection PhpUnusedLocalVariableInspection */
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$unlocker = new ScopedCallback( function () use ( $dbw, $key ) {
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$dbw->unlock( $key, __METHOD__ );
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} );
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$cutoffTime = time() - self::PRESUME_FRESH_TTL_SEC;
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// Reuse any freshly build matching edit stash cache
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$editInfo = $cache->get( $key );
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if ( $editInfo && wfTimestamp( TS_UNIX, $editInfo->timestamp ) >= $cutoffTime ) {
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$alreadyCached = true;
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} else {
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$format = $content->getDefaultFormat();
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$editInfo = $page->prepareContentForEdit( $content, null, $user, $format, false );
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$alreadyCached = false;
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}
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if ( $editInfo && $editInfo->output ) {
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// Let extensions add ParserOutput metadata or warm other caches
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Hooks::run( 'ParserOutputStashForEdit',
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[ $page, $content, $editInfo->output, $summary, $user ] );
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$titleStr = (string)$title;
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if ( $alreadyCached ) {
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$logger->debug( "Already cached parser output for key '{cachekey}' ('{title}').",
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[ 'cachekey' => $key, 'title' => $titleStr ] );
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return self::ERROR_NONE;
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}
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list( $stashInfo, $ttl, $code ) = self::buildStashValue(
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$editInfo->pstContent,
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$editInfo->output,
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$editInfo->timestamp,
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$user
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);
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if ( $stashInfo ) {
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$ok = $cache->set( $key, $stashInfo, $ttl );
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if ( $ok ) {
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$logger->debug( "Cached parser output for key '{cachekey}' ('{title}').",
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[ 'cachekey' => $key, 'title' => $titleStr ] );
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return self::ERROR_NONE;
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} else {
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$logger->error( "Failed to cache parser output for key '{cachekey}' ('{title}').",
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[ 'cachekey' => $key, 'title' => $titleStr ] );
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return self::ERROR_CACHE;
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}
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} else {
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$logger->info( "Uncacheable parser output for key '{cachekey}' ('{title}') [{code}].",
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[ 'cachekey' => $key, 'title' => $titleStr, 'code' => $code ] );
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return self::ERROR_UNCACHEABLE;
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}
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}
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return self::ERROR_PARSE;
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}
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/**
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* Check that a prepared edit is in cache and still up-to-date
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*
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* This method blocks if the prepared edit is already being rendered,
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* waiting until rendering finishes before doing final validity checks.
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*
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* The cache is rejected if template or file changes are detected.
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* Note that foreign template or file transclusions are not checked.
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*
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* The result is a map (pstContent,output,timestamp) with fields
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* extracted directly from WikiPage::prepareContentForEdit().
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*
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* @param Title $title
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* @param Content $content
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* @param User $user User to get parser options from
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* @return stdClass|bool Returns false on cache miss
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*/
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public static function checkCache( Title $title, Content $content, User $user ) {
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if ( $user->isBot() ) {
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return false; // bots never stash - don't pollute stats
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}
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$cache = ObjectCache::getLocalClusterInstance();
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$logger = LoggerFactory::getInstance( 'StashEdit' );
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$stats = MediaWikiServices::getInstance()->getStatsdDataFactory();
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$key = self::getStashKey( $title, self::getContentHash( $content ), $user );
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$editInfo = $cache->get( $key );
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if ( !is_object( $editInfo ) ) {
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$start = microtime( true );
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// We ignore user aborts and keep parsing. Block on any prior parsing
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// so as to use its results and make use of the time spent parsing.
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// Skip this logic if there no master connection in case this method
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// is called on an HTTP GET request for some reason.
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$lb = MediaWikiServices::getInstance()->getDBLoadBalancer();
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$dbw = $lb->getAnyOpenConnection( $lb->getWriterIndex() );
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if ( $dbw && $dbw->lock( $key, __METHOD__, 30 ) ) {
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$editInfo = $cache->get( $key );
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$dbw->unlock( $key, __METHOD__ );
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}
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$timeMs = 1000 * max( 0, microtime( true ) - $start );
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$stats->timing( 'editstash.lock_wait_time', $timeMs );
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}
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if ( !is_object( $editInfo ) || !$editInfo->output ) {
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$stats->increment( 'editstash.cache_misses.no_stash' );
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$logger->debug( "Empty cache for key '$key' ('$title'); user '{$user->getName()}'." );
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return false;
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}
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$age = time() - wfTimestamp( TS_UNIX, $editInfo->output->getCacheTime() );
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if ( $age <= self::PRESUME_FRESH_TTL_SEC ) {
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// Assume nothing changed in this time
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$stats->increment( 'editstash.cache_hits.presumed_fresh' );
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$logger->debug( "Timestamp-based cache hit for key '$key' (age: $age sec)." );
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} elseif ( isset( $editInfo->edits ) && $editInfo->edits === $user->getEditCount() ) {
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// Logged-in user made no local upload/template edits in the meantime
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$stats->increment( 'editstash.cache_hits.presumed_fresh' );
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$logger->debug( "Edit count based cache hit for key '$key' (age: $age sec)." );
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} elseif ( $user->isAnon()
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&& self::lastEditTime( $user ) < $editInfo->output->getCacheTime()
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) {
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// Logged-out user made no local upload/template edits in the meantime
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$stats->increment( 'editstash.cache_hits.presumed_fresh' );
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$logger->debug( "Edit check based cache hit for key '$key' (age: $age sec)." );
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} else {
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// User may have changed included content
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$editInfo = false;
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}
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if ( !$editInfo ) {
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$stats->increment( 'editstash.cache_misses.proven_stale' );
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$logger->info( "Stale cache for key '$key'; old key with outside edits. (age: $age sec)" );
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} elseif ( $editInfo->output->getFlag( 'vary-revision' ) ) {
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// This can be used for the initial parse, e.g. for filters or doEditContent(),
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// but a second parse will be triggered in doEditUpdates(). This is not optimal.
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$logger->info( "Cache for key '$key' ('$title') has vary_revision." );
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} elseif ( $editInfo->output->getFlag( 'vary-revision-id' ) ) {
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// Similar to the above if we didn't guess the ID correctly.
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$logger->info( "Cache for key '$key' ('$title') has vary_revision_id." );
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}
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return $editInfo;
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}
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/**
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* @param User $user
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* @return string|null TS_MW timestamp or null
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*/
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private static function lastEditTime( User $user ) {
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$time = wfGetDB( DB_REPLICA )->selectField(
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'recentchanges',
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'MAX(rc_timestamp)',
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[ 'rc_user_text' => $user->getName() ],
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__METHOD__
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);
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return wfTimestampOrNull( TS_MW, $time );
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}
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/**
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* Get hash of the content, factoring in model/format
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*
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* @param Content $content
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* @return string
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*/
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private static function getContentHash( Content $content ) {
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return sha1( implode( "\n", [
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$content->getModel(),
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$content->getDefaultFormat(),
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$content->serialize( $content->getDefaultFormat() )
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] ) );
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}
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/**
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* Get the temporary prepared edit stash key for a user
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*
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* This key can be used for caching prepared edits provided:
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* - a) The $user was used for PST options
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* - b) The parser output was made from the PST using cannonical matching options
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*
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* @param Title $title
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* @param string $contentHash Result of getContentHash()
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* @param User $user User to get parser options from
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* @return string
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*/
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private static function getStashKey( Title $title, $contentHash, User $user ) {
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return ObjectCache::getLocalClusterInstance()->makeKey(
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'prepared-edit',
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md5( $title->getPrefixedDBkey() ),
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// Account for the edit model/text
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$contentHash,
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// Account for user name related variables like signatures
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md5( $user->getId() . "\n" . $user->getName() )
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);
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}
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/**
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* Build a value to store in memcached based on the PST content and parser output
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*
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* This makes a simple version of WikiPage::prepareContentForEdit() as stash info
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*
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* @param Content $pstContent Pre-Save transformed content
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* @param ParserOutput $parserOutput
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* @param string $timestamp TS_MW
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* @param User $user
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* @return array (stash info array, TTL in seconds, info code) or (null, 0, info code)
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*/
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private static function buildStashValue(
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Content $pstContent, ParserOutput $parserOutput, $timestamp, User $user
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) {
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// If an item is renewed, mind the cache TTL determined by config and parser functions.
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// Put an upper limit on the TTL for sanity to avoid extreme template/file staleness.
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$since = time() - wfTimestamp( TS_UNIX, $parserOutput->getTimestamp() );
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$ttl = min( $parserOutput->getCacheExpiry() - $since, self::MAX_CACHE_TTL );
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// Avoid extremely stale user signature timestamps (T84843)
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if ( $parserOutput->getFlag( 'user-signature' ) ) {
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$ttl = min( $ttl, self::MAX_SIGNATURE_TTL );
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}
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if ( $ttl <= 0 ) {
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return [ null, 0, 'no_ttl' ];
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}
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// Only store what is actually needed
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$stashInfo = (object)[
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'pstContent' => $pstContent,
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'output' => $parserOutput,
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'timestamp' => $timestamp,
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'edits' => $user->getEditCount()
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];
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return [ $stashInfo, $ttl, 'ok' ];
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}
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public function getAllowedParams() {
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return [
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'title' => [
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ApiBase::PARAM_TYPE => 'string',
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ApiBase::PARAM_REQUIRED => true
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],
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'section' => [
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ApiBase::PARAM_TYPE => 'string',
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],
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'sectiontitle' => [
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ApiBase::PARAM_TYPE => 'string'
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],
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'text' => [
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ApiBase::PARAM_TYPE => 'text',
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ApiBase::PARAM_DFLT => null
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],
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'stashedtexthash' => [
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ApiBase::PARAM_TYPE => 'string',
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ApiBase::PARAM_DFLT => null
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],
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'summary' => [
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ApiBase::PARAM_TYPE => 'string',
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],
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'contentmodel' => [
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ApiBase::PARAM_TYPE => ContentHandler::getContentModels(),
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ApiBase::PARAM_REQUIRED => true
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],
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'contentformat' => [
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ApiBase::PARAM_TYPE => ContentHandler::getAllContentFormats(),
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ApiBase::PARAM_REQUIRED => true
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],
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'baserevid' => [
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ApiBase::PARAM_TYPE => 'integer',
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ApiBase::PARAM_REQUIRED => true
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]
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];
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}
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public function needsToken() {
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return 'csrf';
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}
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public function mustBePosted() {
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return true;
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}
|
|
|
|
public function isWriteMode() {
|
|
return true;
|
|
}
|
|
|
|
public function isInternal() {
|
|
return true;
|
|
}
|
|
}
|