ApiQueryLinks.php

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<?php
class ApiQueryLinks extends ApiQueryGeneratorBase {

        const LINKS = 'links';
        const TEMPLATES = 'templates';

        private $table, $prefix, $description, $helpUrl;

        public function __construct( $query, $moduleName ) {
                switch ( $moduleName ) {
                        case self::LINKS:
                                $this->table = 'pagelinks';
                                $this->prefix = 'pl';
                                $this->description = 'link';
                                $this->titlesParam = 'titles';
                                $this->titlesParamDescription = 'Only list links to these titles. Useful for checking whether a certain page links to a certain title.';
                                $this->helpUrl = 'https://www.mediawiki.org/wiki/API:Properties#links_.2F_pl';
                                break;
                        case self::TEMPLATES:
                                $this->table = 'templatelinks';
                                $this->prefix = 'tl';
                                $this->description = 'template';
                                $this->titlesParam = 'templates';
                                $this->titlesParamDescription = 'Only list these templates. Useful for checking whether a certain page uses a certain template.';
                                $this->helpUrl = 'https://www.mediawiki.org/wiki/API:Properties#templates_.2F_tl';
                                break;
                        default:
                                ApiBase::dieDebug( __METHOD__, 'Unknown module name' );
                }

                parent::__construct( $query, $moduleName, $this->prefix );
        }

        public function execute() {
                $this->run();
        }

        public function getCacheMode( $params ) {
                return 'public';
        }

        public function executeGenerator( $resultPageSet ) {
                $this->run( $resultPageSet );
        }

        private function run( $resultPageSet = null ) {
                if ( $this->getPageSet()->getGoodTitleCount() == 0 ) {
                        return; // nothing to do
                }

                $params = $this->extractRequestParams();

                $this->addFields( array(
                        $this->prefix . '_from AS pl_from',
                        $this->prefix . '_namespace AS pl_namespace',
                        $this->prefix . '_title AS pl_title'
                ) );

                $this->addTables( $this->table );
                $this->addWhereFld( $this->prefix . '_from', array_keys( $this->getPageSet()->getGoodTitles() ) );
                $this->addWhereFld( $this->prefix . '_namespace', $params['namespace'] );

                if ( !is_null( $params[$this->titlesParam] ) ) {
                        $lb = new LinkBatch;
                        foreach ( $params[$this->titlesParam] as $t ) {
                                $title = Title::newFromText( $t );
                                if ( !$title ) {
                                        $this->setWarning( "\"$t\" is not a valid title" );
                                } else {
                                        $lb->addObj( $title );
                                }
                        }
                        $cond = $lb->constructSet( $this->prefix, $this->getDB() );
                        if ( $cond ) {
                                $this->addWhere( $cond );
                        }
                }

                if ( !is_null( $params['continue'] ) ) {
                        $cont = explode( '|', $params['continue'] );
                        if ( count( $cont ) != 3 ) {
                                $this->dieUsage( 'Invalid continue param. You should pass the ' .
                                        'original value returned by the previous query', '_badcontinue' );
                        }
                        $plfrom = intval( $cont[0] );
                        $plns = intval( $cont[1] );
                        $pltitle = $this->getDB()->strencode( $this->titleToKey( $cont[2] ) );
                        $this->addWhere(
                                "{$this->prefix}_from > $plfrom OR " .
                                "({$this->prefix}_from = $plfrom AND " .
                                "({$this->prefix}_namespace > $plns OR " .
                                "({$this->prefix}_namespace = $plns AND " .
                                "{$this->prefix}_title >= '$pltitle')))"
                        );
                }

                $dir = ( $params['dir'] == 'descending' ? ' DESC' : '' );
                // Here's some MySQL craziness going on: if you use WHERE foo='bar'
                // and later ORDER BY foo MySQL doesn't notice the ORDER BY is pointless
                // but instead goes and filesorts, because the index for foo was used
                // already. To work around this, we drop constant fields in the WHERE
                // clause from the ORDER BY clause
                $order = array();
                if ( count( $this->getPageSet()->getGoodTitles() ) != 1 ) {
                        $order[] = $this->prefix . '_from' . $dir;
                }
                if ( count( $params['namespace'] ) != 1 ) {
                        $order[] = $this->prefix . '_namespace' . $dir;
                }

                $order[] = $this->prefix . "_title" . $dir;
                $this->addOption( 'ORDER BY', $order );
                $this->addOption( 'USE INDEX', $this->prefix . '_from' );
                $this->addOption( 'LIMIT', $params['limit'] + 1 );

                $res = $this->select( __METHOD__ );

                if ( is_null( $resultPageSet ) ) {
                        $count = 0;
                        foreach ( $res as $row ) {
                                if ( ++$count > $params['limit'] ) {
                                        // We've reached the one extra which shows that
                                        // there are additional pages to be had. Stop here...
                                        $this->setContinueEnumParameter( 'continue',
                                                "{$row->pl_from}|{$row->pl_namespace}|" .
                                                $this->keyToTitle( $row->pl_title ) );
                                        break;
                                }
                                $vals = array();
                                ApiQueryBase::addTitleInfo( $vals, Title::makeTitle( $row->pl_namespace, $row->pl_title ) );
                                $fit = $this->addPageSubItem( $row->pl_from, $vals );
                                if ( !$fit ) {
                                        $this->setContinueEnumParameter( 'continue',
                                                "{$row->pl_from}|{$row->pl_namespace}|" .
                                                $this->keyToTitle( $row->pl_title ) );
                                        break;
                                }
                        }
                } else {
                        $titles = array();
                        $count = 0;
                        foreach ( $res as $row ) {
                                if ( ++$count > $params['limit'] ) {
                                        // We've reached the one extra which shows that
                                        // there are additional pages to be had. Stop here...
                                        $this->setContinueEnumParameter( 'continue',
                                                "{$row->pl_from}|{$row->pl_namespace}|" .
                                                $this->keyToTitle( $row->pl_title ) );
                                        break;
                                }
                                $titles[] = Title::makeTitle( $row->pl_namespace, $row->pl_title );
                        }
                        $resultPageSet->populateFromTitles( $titles );
                }
        }

        public function getAllowedParams() {
                return array(
                        'namespace' => array(
                                ApiBase::PARAM_TYPE => 'namespace',
                                ApiBase::PARAM_ISMULTI => true
                        ),
                        'limit' => array(
                                ApiBase::PARAM_DFLT => 10,
                                ApiBase::PARAM_TYPE => 'limit',
                                ApiBase::PARAM_MIN => 1,
                                ApiBase::PARAM_MAX => ApiBase::LIMIT_BIG1,
                                ApiBase::PARAM_MAX2 => ApiBase::LIMIT_BIG2
                        ),
                        'continue' => null,
                        $this->titlesParam => array(
                                ApiBase::PARAM_ISMULTI => true,
                        ),
                        'dir' => array(
                                ApiBase::PARAM_DFLT => 'ascending',
                                ApiBase::PARAM_TYPE => array(
                                        'ascending',
                                        'descending'
                                )
                        ),
                );
        }

        public function getParamDescription() {
                $desc = $this->description;
                return array(
                        'namespace' => "Show {$desc}s in this namespace(s) only",
                        'limit' => "How many {$desc}s to return",
                        'continue' => 'When more results are available, use this to continue',
                        $this->titlesParam => $this->titlesParamDescription,
                        'dir' => 'The direction in which to list',
                );
        }

        public function getDescription() {
                return "Returns all {$this->description}s from the given page(s)";
        }

        public function getExamples() {
                $desc = $this->description;
                $name = $this->getModuleName();
                return array(
                        "api.php?action=query&prop={$name}&titles=Main%20Page" => "Get {$desc}s from the [[Main Page]]:",
                        "api.php?action=query&generator={$name}&titles=Main%20Page&prop=info" => "Get information about the {$desc} pages in the [[Main Page]]:",
                        "api.php?action=query&prop={$name}&titles=Main%20Page&{$this->prefix}namespace=2|10" => "Get {$desc}s from the Main Page in the User and Template namespaces:",
                );
        }

        public function getHelpUrls() {
                return $this->helpUrl;
        }

        public function getVersion() {
                return __CLASS__ . ': $Id$';
        }
}