ApiQuery.php

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<?php
use Wikimedia\Rdbms\IDatabase;

class ApiQuery extends ApiBase {

    private static $QueryPropModules = [
        'categories' => ApiQueryCategories::class,
        'categoryinfo' => ApiQueryCategoryInfo::class,
        'contributors' => ApiQueryContributors::class,
        'deletedrevisions' => ApiQueryDeletedRevisions::class,
        'duplicatefiles' => ApiQueryDuplicateFiles::class,
        'extlinks' => ApiQueryExternalLinks::class,
        'fileusage' => ApiQueryBacklinksprop::class,
        'images' => ApiQueryImages::class,
        'imageinfo' => ApiQueryImageInfo::class,
        'info' => ApiQueryInfo::class,
        'links' => ApiQueryLinks::class,
        'linkshere' => ApiQueryBacklinksprop::class,
        'iwlinks' => ApiQueryIWLinks::class,
        'langlinks' => ApiQueryLangLinks::class,
        'pageprops' => ApiQueryPageProps::class,
        'redirects' => ApiQueryBacklinksprop::class,
        'revisions' => ApiQueryRevisions::class,
        'stashimageinfo' => ApiQueryStashImageInfo::class,
        'templates' => ApiQueryLinks::class,
        'transcludedin' => ApiQueryBacklinksprop::class,
    ];

    private static $QueryListModules = [
        'allcategories' => ApiQueryAllCategories::class,
        'alldeletedrevisions' => ApiQueryAllDeletedRevisions::class,
        'allfileusages' => ApiQueryAllLinks::class,
        'allimages' => ApiQueryAllImages::class,
        'alllinks' => ApiQueryAllLinks::class,
        'allpages' => ApiQueryAllPages::class,
        'allredirects' => ApiQueryAllLinks::class,
        'allrevisions' => ApiQueryAllRevisions::class,
        'mystashedfiles' => ApiQueryMyStashedFiles::class,
        'alltransclusions' => ApiQueryAllLinks::class,
        'allusers' => ApiQueryAllUsers::class,
        'backlinks' => ApiQueryBacklinks::class,
        'blocks' => ApiQueryBlocks::class,
        'categorymembers' => ApiQueryCategoryMembers::class,
        'deletedrevs' => ApiQueryDeletedrevs::class,
        'embeddedin' => ApiQueryBacklinks::class,
        'exturlusage' => ApiQueryExtLinksUsage::class,
        'filearchive' => ApiQueryFilearchive::class,
        'imageusage' => ApiQueryBacklinks::class,
        'iwbacklinks' => ApiQueryIWBacklinks::class,
        'langbacklinks' => ApiQueryLangBacklinks::class,
        'logevents' => ApiQueryLogEvents::class,
        'pageswithprop' => ApiQueryPagesWithProp::class,
        'pagepropnames' => ApiQueryPagePropNames::class,
        'prefixsearch' => ApiQueryPrefixSearch::class,
        'protectedtitles' => ApiQueryProtectedTitles::class,
        'querypage' => ApiQueryQueryPage::class,
        'random' => ApiQueryRandom::class,
        'recentchanges' => ApiQueryRecentChanges::class,
        'search' => ApiQuerySearch::class,
        'tags' => ApiQueryTags::class,
        'usercontribs' => ApiQueryUserContribs::class,
        'users' => ApiQueryUsers::class,
        'watchlist' => ApiQueryWatchlist::class,
        'watchlistraw' => ApiQueryWatchlistRaw::class,
    ];

    private static $QueryMetaModules = [
        'allmessages' => ApiQueryAllMessages::class,
        'authmanagerinfo' => ApiQueryAuthManagerInfo::class,
        'siteinfo' => ApiQuerySiteinfo::class,
        'userinfo' => ApiQueryUserInfo::class,
        'filerepoinfo' => ApiQueryFileRepoInfo::class,
        'tokens' => ApiQueryTokens::class,
        'languageinfo' => ApiQueryLanguageinfo::class,
    ];

    private $mPageSet;

    private $mParams;
    private $mNamedDB = [];
    private $mModuleMgr;

    public function __construct( ApiMain $main, $action ) {
        parent::__construct( $main, $action );

        $this->mModuleMgr = new ApiModuleManager( $this );

        // Allow custom modules to be added in LocalSettings.php
        $config = $this->getConfig();
        $this->mModuleMgr->addModules( self::$QueryPropModules, 'prop' );
        $this->mModuleMgr->addModules( $config->get( 'APIPropModules' ), 'prop' );
        $this->mModuleMgr->addModules( self::$QueryListModules, 'list' );
        $this->mModuleMgr->addModules( $config->get( 'APIListModules' ), 'list' );
        $this->mModuleMgr->addModules( self::$QueryMetaModules, 'meta' );
        $this->mModuleMgr->addModules( $config->get( 'APIMetaModules' ), 'meta' );

        Hooks::run( 'ApiQuery::moduleManager', [ $this->mModuleMgr ] );

        // Create PageSet that will process titles/pageids/revids/generator
        $this->mPageSet = new ApiPageSet( $this );
    }

    public function getModuleManager() {
        return $this->mModuleMgr;
    }

    public function getNamedDB( $name, $db, $groups ) {
        if ( !array_key_exists( $name, $this->mNamedDB ) ) {
            $this->mNamedDB[$name] = wfGetDB( $db, $groups );
        }

        return $this->mNamedDB[$name];
    }

    public function getPageSet() {
        return $this->mPageSet;
    }

    public function getCustomPrinter() {
        // If &exportnowrap is set, use the raw formatter
        if ( $this->getParameter( 'export' ) &&
            $this->getParameter( 'exportnowrap' )
        ) {
            return new ApiFormatRaw( $this->getMain(),
                $this->getMain()->createPrinterByName( 'xml' ) );
        } else {
            return null;
        }
    }

    public function execute() {
        $this->mParams = $this->extractRequestParams();

        // Instantiate requested modules
        $allModules = [];
        $this->instantiateModules( $allModules, 'prop' );
        $propModules = array_keys( $allModules );
        $this->instantiateModules( $allModules, 'list' );
        $this->instantiateModules( $allModules, 'meta' );

        // Filter modules based on continue parameter
        $continuationManager = new ApiContinuationManager( $this, $allModules, $propModules );
        $this->setContinuationManager( $continuationManager );
        $modules = $continuationManager->getRunModules();

        if ( !$continuationManager->isGeneratorDone() ) {
            // Query modules may optimize data requests through the $this->getPageSet()
            // object by adding extra fields from the page table.
            foreach ( $modules as $module ) {
                $module->requestExtraData( $this->mPageSet );
            }
            // Populate page/revision information
            $this->mPageSet->execute();
            // Record page information (title, namespace, if exists, etc)
            $this->outputGeneralPageInfo();
        } else {
            $this->mPageSet->executeDryRun();
        }

        $cacheMode = $this->mPageSet->getCacheMode();

        // Execute all unfinished modules
        foreach ( $modules as $module ) {
            $params = $module->extractRequestParams();
            $cacheMode = $this->mergeCacheMode(
                $cacheMode, $module->getCacheMode( $params ) );
            $module->execute();
            Hooks::run( 'APIQueryAfterExecute', [ &$module ] );
        }

        // Set the cache mode
        $this->getMain()->setCacheMode( $cacheMode );

        // Write the continuation data into the result
        $this->setContinuationManager( null );
        if ( $this->mParams['rawcontinue'] ) {
            $data = $continuationManager->getRawNonContinuation();
            if ( $data ) {
                $this->getResult()->addValue( null, 'query-noncontinue', $data,
                    ApiResult::ADD_ON_TOP | ApiResult::NO_SIZE_CHECK );
            }
            $data = $continuationManager->getRawContinuation();
            if ( $data ) {
                $this->getResult()->addValue( null, 'query-continue', $data,
                    ApiResult::ADD_ON_TOP | ApiResult::NO_SIZE_CHECK );
            }
        } else {
            $continuationManager->setContinuationIntoResult( $this->getResult() );
        }
    }

    protected function mergeCacheMode( $cacheMode, $modCacheMode ) {
        if ( $modCacheMode === 'anon-public-user-private' ) {
            if ( $cacheMode !== 'private' ) {
                $cacheMode = 'anon-public-user-private';
            }
        } elseif ( $modCacheMode === 'public' ) {
            // do nothing, if it's public already it will stay public
        } else {
            $cacheMode = 'private';
        }

        return $cacheMode;
    }

    private function instantiateModules( &$modules, $param ) {
        $wasPosted = $this->getRequest()->wasPosted();
        if ( isset( $this->mParams[$param] ) ) {
            foreach ( $this->mParams[$param] as $moduleName ) {
                $instance = $this->mModuleMgr->getModule( $moduleName, $param );
                if ( $instance === null ) {
                    ApiBase::dieDebug( __METHOD__, 'Error instantiating module' );
                }
                if ( !$wasPosted && $instance->mustBePosted() ) {
                    $this->dieWithErrorOrDebug( [ 'apierror-mustbeposted', $moduleName ] );
                }
                // Ignore duplicates. TODO 2.0: die()?
                if ( !array_key_exists( $moduleName, $modules ) ) {
                    $modules[$moduleName] = $instance;
                }
            }
        }
    }

    private function outputGeneralPageInfo() {
        $pageSet = $this->getPageSet();
        $result = $this->getResult();

        // We can't really handle max-result-size failure here, but we need to
        // check anyway in case someone set the limit stupidly low.
        $fit = true;

        $values = $pageSet->getNormalizedTitlesAsResult( $result );
        if ( $values ) {
            $fit = $fit && $result->addValue( 'query', 'normalized', $values );
        }
        $values = $pageSet->getConvertedTitlesAsResult( $result );
        if ( $values ) {
            $fit = $fit && $result->addValue( 'query', 'converted', $values );
        }
        $values = $pageSet->getInterwikiTitlesAsResult( $result, $this->mParams['iwurl'] );
        if ( $values ) {
            $fit = $fit && $result->addValue( 'query', 'interwiki', $values );
        }
        $values = $pageSet->getRedirectTitlesAsResult( $result );
        if ( $values ) {
            $fit = $fit && $result->addValue( 'query', 'redirects', $values );
        }
        $values = $pageSet->getMissingRevisionIDsAsResult( $result );
        if ( $values ) {
            $fit = $fit && $result->addValue( 'query', 'badrevids', $values );
        }

        // Page elements
        $pages = [];

        // Report any missing titles
        foreach ( $pageSet->getMissingTitles() as $fakeId => $title ) {
            $vals = [];
            ApiQueryBase::addTitleInfo( $vals, $title );
            $vals['missing'] = true;
            if ( $title->isKnown() ) {
                $vals['known'] = true;
            }
            $pages[$fakeId] = $vals;
        }
        // Report any invalid titles
        foreach ( $pageSet->getInvalidTitlesAndReasons() as $fakeId => $data ) {
            $pages[$fakeId] = $data + [ 'invalid' => true ];
        }
        // Report any missing page ids
        foreach ( $pageSet->getMissingPageIDs() as $pageid ) {
            $pages[$pageid] = [
                'pageid' => $pageid,
                'missing' => true,
            ];
        }
        // Report special pages
        foreach ( $pageSet->getSpecialTitles() as $fakeId => $title ) {
            $vals = [];
            ApiQueryBase::addTitleInfo( $vals, $title );
            $vals['special'] = true;
            if ( !$title->isKnown() ) {
                $vals['missing'] = true;
            }
            $pages[$fakeId] = $vals;
        }

        // Output general page information for found titles
        foreach ( $pageSet->getGoodTitles() as $pageid => $title ) {
            $vals = [];
            $vals['pageid'] = $pageid;
            ApiQueryBase::addTitleInfo( $vals, $title );
            $pages[$pageid] = $vals;
        }

        if ( count( $pages ) ) {
            $pageSet->populateGeneratorData( $pages );
            ApiResult::setArrayType( $pages, 'BCarray' );

            if ( $this->mParams['indexpageids'] ) {
                $pageIDs = array_keys( ApiResult::stripMetadataNonRecursive( $pages ) );
                // json treats all map keys as strings - converting to match
                $pageIDs = array_map( 'strval', $pageIDs );
                ApiResult::setIndexedTagName( $pageIDs, 'id' );
                $fit = $fit && $result->addValue( 'query', 'pageids', $pageIDs );
            }

            ApiResult::setIndexedTagName( $pages, 'page' );
            $fit = $fit && $result->addValue( 'query', 'pages', $pages );
        }

        if ( !$fit ) {
            $this->dieWithError( 'apierror-badconfig-resulttoosmall', 'badconfig' );
        }

        if ( $this->mParams['export'] ) {
            $this->doExport( $pageSet, $result );
        }
    }

    private function doExport( $pageSet, $result ) {
        $exportTitles = [];
        $titles = $pageSet->getGoodTitles();
        if ( count( $titles ) ) {
            foreach ( $titles as $title ) {
                if ( $this->getPermissionManager()->userCan( 'read', $this->getUser(), $title ) ) {
                    $exportTitles[] = $title;
                }
            }
        }

        $exporter = new WikiExporter( $this->getDB() );
        $sink = new DumpStringOutput;
        $exporter->setOutputSink( $sink );
        $exporter->setSchemaVersion( $this->mParams['exportschema'] );
        $exporter->openStream();
        foreach ( $exportTitles as $title ) {
            $exporter->pageByTitle( $title );
        }
        $exporter->closeStream();

        // Don't check the size of exported stuff
        // It's not continuable, so it would cause more
        // problems than it'd solve
        if ( $this->mParams['exportnowrap'] ) {
            $result->reset();
            // Raw formatter will handle this
            $result->addValue( null, 'text', $sink, ApiResult::NO_SIZE_CHECK );
            $result->addValue( null, 'mime', 'text/xml', ApiResult::NO_SIZE_CHECK );
            $result->addValue( null, 'filename', 'export.xml', ApiResult::NO_SIZE_CHECK );
        } else {
            $result->addValue( 'query', 'export', $sink, ApiResult::NO_SIZE_CHECK );
            $result->addValue( 'query', ApiResult::META_BC_SUBELEMENTS, [ 'export' ] );
        }
    }

    public function getAllowedParams( $flags = 0 ) {
        $result = [
            'prop' => [
                ApiBase::PARAM_ISMULTI => true,
                ApiBase::PARAM_TYPE => 'submodule',
            ],
            'list' => [
                ApiBase::PARAM_ISMULTI => true,
                ApiBase::PARAM_TYPE => 'submodule',
            ],
            'meta' => [
                ApiBase::PARAM_ISMULTI => true,
                ApiBase::PARAM_TYPE => 'submodule',
            ],
            'indexpageids' => false,
            'export' => false,
            'exportnowrap' => false,
            'exportschema' => [
                ApiBase::PARAM_DFLT => WikiExporter::schemaVersion(),
                ApiBase::PARAM_TYPE => XmlDumpWriter::$supportedSchemas,
            ],
            'iwurl' => false,
            'continue' => [
                ApiBase::PARAM_HELP_MSG => 'api-help-param-continue',
            ],
            'rawcontinue' => false,
        ];
        if ( $flags ) {
            $result += $this->getPageSet()->getFinalParams( $flags );
        }

        return $result;
    }

    public function isReadMode() {
        // We need to make an exception for certain meta modules that should be
        // accessible even without the 'read' right. Restrict the exception as
        // much as possible: no other modules allowed, and no pageset
        // parameters either. We do allow the 'rawcontinue' and 'indexpageids'
        // parameters since frameworks might add these unconditionally and they
        // can't expose anything here.
        $this->mParams = $this->extractRequestParams();
        $params = array_filter(
            array_diff_key(
                $this->mParams + $this->getPageSet()->extractRequestParams(),
                [ 'rawcontinue' => 1, 'indexpageids' => 1 ]
            )
        );
        if ( array_keys( $params ) !== [ 'meta' ] ) {
            return true;
        }

        // Ask each module if it requires read mode. Any true => this returns
        // true.
        $modules = [];
        $this->instantiateModules( $modules, 'meta' );
        foreach ( $modules as $module ) {
            if ( $module->isReadMode() ) {
                return true;
            }
        }

        return false;
    }

    protected function getExamplesMessages() {
        return [
            'action=query&prop=revisions&meta=siteinfo&' .
                'titles=Main%20Page&rvprop=user|comment&continue='
                => 'apihelp-query-example-revisions',
            'action=query&generator=allpages&gapprefix=API/&prop=revisions&continue='
                => 'apihelp-query-example-allpages',
        ];
    }

    public function getHelpUrls() {
        return [
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Query',
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Meta',
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Properties',
            'https://www.mediawiki.org/wiki/Special:MyLanguage/API:Lists',
        ];
    }
}