Move ILoadBalancer to Rdbms namespace

[mediawiki.git] / includes / resourceloader / ResourceLoaderWikiModule.php

<?php
/**
 * Abstraction for ResourceLoader modules that pull from wiki pages.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @author Trevor Parscal
 * @author Roan Kattouw
 */

/**
 * Abstraction for ResourceLoader modules which pull from wiki pages
 *
 * This can only be used for wiki pages in the MediaWiki and User namespaces,
 * because of its dependence on the functionality of Title::isCssJsSubpage
 * and Title::isCssOrJsPage().
 *
 * This module supports being used as a placeholder for a module on a remote wiki.
 * To do so, getDB() must be overloaded to return a foreign database object that
 * allows local wikis to query page metadata.
 *
 * Safe for calls on local wikis are:
 * - Option getters:
 *   - getGroup()
 *   - getPages()
 * - Basic methods that strictly involve the foreign database
 *   - getDB()
 *   - isKnownEmpty()
 *   - getTitleInfo()
 */
class ResourceLoaderWikiModule extends ResourceLoaderModule {

        // Origin defaults to users with sitewide authority
        protected $origin = self::ORIGIN_USER_SITEWIDE;

        // In-process cache for title info
        protected $titleInfo = [];

        // List of page names that contain CSS
        protected $styles = [];

        // List of page names that contain JavaScript
        protected $scripts = [];

        // Group of module
        protected $group;

        /**
         * @param array $options For back-compat, this can be omitted in favour of overwriting getPages.
         */
        public function __construct( array $options = null ) {
                if ( is_null( $options ) ) {
                        return;
                }

                foreach ( $options as $member => $option ) {
                        switch ( $member ) {
                                case 'styles':
                                case 'scripts':
                                case 'group':
                                case 'targets':
                                        $this->{$member} = $option;
                                        break;
                        }
                }
        }

        /**
         * Subclasses should return an associative array of resources in the module.
         * Keys should be the title of a page in the MediaWiki or User namespace.
         *
         * Values should be a nested array of options.  The supported keys are 'type' and
         * (CSS only) 'media'.
         *
         * For scripts, 'type' should be 'script'.
         *
         * For stylesheets, 'type' should be 'style'.
         * There is an optional media key, the value of which can be the
         * medium ('screen', 'print', etc.) of the stylesheet.
         *
         * @param ResourceLoaderContext $context
         * @return array
         */
        protected function getPages( ResourceLoaderContext $context ) {
                $config = $this->getConfig();
                $pages = [];

                // Filter out pages from origins not allowed by the current wiki configuration.
                if ( $config->get( 'UseSiteJs' ) ) {
                        foreach ( $this->scripts as $script ) {
                                $pages[$script] = [ 'type' => 'script' ];
                        }
                }

                if ( $config->get( 'UseSiteCss' ) ) {
                        foreach ( $this->styles as $style ) {
                                $pages[$style] = [ 'type' => 'style' ];
                        }
                }

                return $pages;
        }

        /**
         * Get group name
         *
         * @return string
         */
        public function getGroup() {
                return $this->group;
        }

        /**
         * Get the Database object used in getTitleInfo().
         *
         * Defaults to the local replica DB. Subclasses may want to override this to return a foreign
         * database object, or null if getTitleInfo() shouldn't access the database.
         *
         * NOTE: This ONLY works for getTitleInfo() and isKnownEmpty(), NOT FOR ANYTHING ELSE.
         * In particular, it doesn't work for getContent() or getScript() etc.
         *
         * @return IDatabase|null
         */
        protected function getDB() {
                return wfGetDB( DB_REPLICA );
        }

        /**
         * @param string $titleText
         * @return null|string
         */
        protected function getContent( $titleText ) {
                $title = Title::newFromText( $titleText );
                if ( !$title ) {
                        return null;
                }

                $handler = ContentHandler::getForTitle( $title );
                if ( $handler->isSupportedFormat( CONTENT_FORMAT_CSS ) ) {
                        $format = CONTENT_FORMAT_CSS;
                } elseif ( $handler->isSupportedFormat( CONTENT_FORMAT_JAVASCRIPT ) ) {
                        $format = CONTENT_FORMAT_JAVASCRIPT;
                } else {
                        return null;
                }

                $revision = Revision::newKnownCurrent( wfGetDB( DB_REPLICA ), $title->getArticleID(),
                        $title->getLatestRevID() );
                if ( !$revision ) {
                        return null;
                }
                $revision->setTitle( $title );
                $content = $revision->getContent( Revision::RAW );

                if ( !$content ) {
                        wfDebugLog( 'resourceloader', __METHOD__ . ': failed to load content of JS/CSS page!' );
                        return null;
                }

                return $content->serialize( $format );
        }

        /**
         * @param ResourceLoaderContext $context
         * @return string
         */
        public function getScript( ResourceLoaderContext $context ) {
                $scripts = '';
                foreach ( $this->getPages( $context ) as $titleText => $options ) {
                        if ( $options['type'] !== 'script' ) {
                                continue;
                        }
                        $script = $this->getContent( $titleText );
                        if ( strval( $script ) !== '' ) {
                                $script = $this->validateScriptFile( $titleText, $script );
                                $scripts .= ResourceLoader::makeComment( $titleText ) . $script . "\n";
                        }
                }
                return $scripts;
        }

        /**
         * @param ResourceLoaderContext $context
         * @return array
         */
        public function getStyles( ResourceLoaderContext $context ) {
                $styles = [];
                foreach ( $this->getPages( $context ) as $titleText => $options ) {
                        if ( $options['type'] !== 'style' ) {
                                continue;
                        }
                        $media = isset( $options['media'] ) ? $options['media'] : 'all';
                        $style = $this->getContent( $titleText );
                        if ( strval( $style ) === '' ) {
                                continue;
                        }
                        if ( $this->getFlip( $context ) ) {
                                $style = CSSJanus::transform( $style, true, false );
                        }
                        $style = MemoizedCallable::call( 'CSSMin::remap',
                                [ $style, false, $this->getConfig()->get( 'ScriptPath' ), true ] );
                        if ( !isset( $styles[$media] ) ) {
                                $styles[$media] = [];
                        }
                        $style = ResourceLoader::makeComment( $titleText ) . $style;
                        $styles[$media][] = $style;
                }
                return $styles;
        }

        /**
         * Disable module content versioning.
         *
         * This class does not support generating content outside of a module
         * request due to foreign database support.
         *
         * See getDefinitionSummary() for meta-data versioning.
         *
         * @return bool
         */
        public function enableModuleContentVersion() {
                return false;
        }

        /**
         * @param ResourceLoaderContext $context
         * @return array
         */
        public function getDefinitionSummary( ResourceLoaderContext $context ) {
                $summary = parent::getDefinitionSummary( $context );
                $summary[] = [
                        'pages' => $this->getPages( $context ),
                        // Includes meta data of current revisions
                        'titleInfo' => $this->getTitleInfo( $context ),
                ];
                return $summary;
        }

        /**
         * @param ResourceLoaderContext $context
         * @return bool
         */
        public function isKnownEmpty( ResourceLoaderContext $context ) {
                $revisions = $this->getTitleInfo( $context );

                // For user modules, don't needlessly load if there are no non-empty pages
                if ( $this->getGroup() === 'user' ) {
                        foreach ( $revisions as $revision ) {
                                if ( $revision['page_len'] > 0 ) {
                                        // At least one non-empty page, module should be loaded
                                        return false;
                                }
                        }
                        return true;
                }

                // Bug 68488: For other modules (i.e. ones that are called in cached html output) only check
                // page existance. This ensures that, if some pages in a module are temporarily blanked,
                // we don't end omit the module's script or link tag on some pages.
                return count( $revisions ) === 0;
        }

        private function setTitleInfo( $key, array $titleInfo ) {
                $this->titleInfo[$key] = $titleInfo;
        }

        /**
         * Get the information about the wiki pages for a given context.
         * @param ResourceLoaderContext $context
         * @return array Keyed by page name
         */
        protected function getTitleInfo( ResourceLoaderContext $context ) {
                $dbr = $this->getDB();
                if ( !$dbr ) {
                        // We're dealing with a subclass that doesn't have a DB
                        return [];
                }

                $pageNames = array_keys( $this->getPages( $context ) );
                sort( $pageNames );
                $key = implode( '|', $pageNames );
                if ( !isset( $this->titleInfo[$key] ) ) {
                        $this->titleInfo[$key] = static::fetchTitleInfo( $dbr, $pageNames, __METHOD__ );
                }
                return $this->titleInfo[$key];
        }

        protected static function fetchTitleInfo( IDatabase $db, array $pages, $fname = __METHOD__ ) {
                $titleInfo = [];
                $batch = new LinkBatch;
                foreach ( $pages as $titleText ) {
                        $title = Title::newFromText( $titleText );
                        if ( $title ) {
                                // Page name may be invalid if user-provided (e.g. gadgets)
                                $batch->addObj( $title );
                        }
                }
                if ( !$batch->isEmpty() ) {
                        $res = $db->select( 'page',
                                // Include page_touched to allow purging if cache is poisoned (T117587, T113916)
                                [ 'page_namespace', 'page_title', 'page_touched', 'page_len', 'page_latest' ],
                                $batch->constructSet( 'page', $db ),
                                $fname
                        );
                        foreach ( $res as $row ) {
                                // Avoid including ids or timestamps of revision/page tables so
                                // that versions are not wasted
                                $title = Title::makeTitle( $row->page_namespace, $row->page_title );
                                $titleInfo[$title->getPrefixedText()] = [
                                        'page_len' => $row->page_len,
                                        'page_latest' => $row->page_latest,
                                        'page_touched' => $row->page_touched,
                                ];
                        }
                }
                return $titleInfo;
        }

        /**
         * @since 1.28
         * @param ResourceLoaderContext $context
         * @param IDatabase $db
         * @param string[] $moduleNames
         */
        public static function preloadTitleInfo(
                ResourceLoaderContext $context, IDatabase $db, array $moduleNames
        ) {
                $rl = $context->getResourceLoader();
                // getDB() can be overridden to point to a foreign database.
                // For now, only preload local. In the future, we could preload by wikiID.
                $allPages = [];
                /** @var ResourceLoaderWikiModule[] $wikiModules */
                $wikiModules = [];
                foreach ( $moduleNames as $name ) {
                        $module = $rl->getModule( $name );
                        if ( $module instanceof self ) {
                                $mDB = $module->getDB();
                                // Subclasses may disable getDB and implement getTitleInfo differently
                                if ( $mDB && $mDB->getWikiID() === $db->getWikiID() ) {
                                        $wikiModules[] = $module;
                                        $allPages += $module->getPages( $context );
                                }
                        }
                }

                $pageNames = array_keys( $allPages );
                sort( $pageNames );
                $hash = sha1( implode( '|', $pageNames ) );

                // Avoid Zend bug where "static::" does not apply LSB in the closure
                $func = [ static::class, 'fetchTitleInfo' ];
                $fname = __METHOD__;

                $cache = ObjectCache::getMainWANInstance();
                $allInfo = $cache->getWithSetCallback(
                        $cache->makeGlobalKey( 'resourceloader', 'titleinfo', $db->getWikiID(), $hash ),
                        $cache::TTL_HOUR,
                        function ( $curVal, &$ttl, array &$setOpts ) use ( $func, $pageNames, $db, $fname ) {
                                $setOpts += Database::getCacheSetOptions( $db );

                                return call_user_func( $func, $db, $pageNames, $fname );
                        },
                        [ 'checkKeys' => [ $cache->makeGlobalKey( 'resourceloader', 'titleinfo', $db->getWikiID() ) ] ]
                );

                foreach ( $wikiModules as $wikiModule ) {
                        $pages = $wikiModule->getPages( $context );
                        // Before we intersect, map the names to canonical form (T145673).
                        $intersect = [];
                        foreach ( $pages as $page => $unused ) {
                                $title = Title::newFromText( $page );
                                if ( $title ) {
                                        $intersect[ $title->getPrefixedText() ] = 1;
                                } else {
                                        // Page name may be invalid if user-provided (e.g. gadgets)
                                        $rl->getLogger()->info(
                                                'Invalid wiki page title "{title}" in ' . __METHOD__,
                                                [ 'title' => $page ]
                                        );
                                }
                        }
                        $info = array_intersect_key( $allInfo, $intersect );
                        $pageNames = array_keys( $pages );
                        sort( $pageNames );
                        $key = implode( '|', $pageNames );
                        $wikiModule->setTitleInfo( $key, $info );
                }
        }

        /**
         * Clear the preloadTitleInfo() cache for all wiki modules on this wiki on
         * page change if it was a JS or CSS page
         *
         * @param Title $title
         * @param Revision|null $old Prior page revision
         * @param Revision|null $new New page revision
         * @param string $wikiId
         * @since 1.28
         */
        public static function invalidateModuleCache(
                Title $title, Revision $old = null, Revision $new = null, $wikiId
        ) {
                static $formats = [ CONTENT_FORMAT_CSS, CONTENT_FORMAT_JAVASCRIPT ];

                if ( $old && in_array( $old->getContentFormat(), $formats ) ) {
                        $purge = true;
                } elseif ( $new && in_array( $new->getContentFormat(), $formats ) ) {
                        $purge = true;
                } else {
                        $purge = ( $title->isCssOrJsPage() || $title->isCssJsSubpage() );
                }

                if ( $purge ) {
                        $cache = ObjectCache::getMainWANInstance();
                        $key = $cache->makeGlobalKey( 'resourceloader', 'titleinfo', $wikiId );
                        $cache->touchCheckKey( $key );
                }
        }

        /**
         * @since 1.28
         * @return string
         */
        public function getType() {
                // Check both because subclasses don't always pass pages via the constructor,
                // they may also override getPages() instead, in which case we should keep
                // defaulting to LOAD_GENERAL and allow them to override getType() separately.
                return ( $this->styles && !$this->scripts ) ? self::LOAD_STYLES : self::LOAD_GENERAL;
        }
}