ApiQueryLangBacklinks.php

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<?php
class ApiQueryLangBacklinks extends ApiQueryGeneratorBase {

        public function __construct( $query, $moduleName ) {
                parent::__construct( $query, $moduleName, 'lbl' );
        }

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

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

        public function run( $resultPageSet = null ) {
                $params = $this->extractRequestParams();

                if ( isset( $params['title'] ) && !isset( $params['lang'] ) ) {
                        $this->dieUsageMsg( array( 'missingparam', 'lang' ) );
                }

                if ( !is_null( $params['continue'] ) ) {
                        $cont = explode( '|', $params['continue'] );
                        $this->dieContinueUsageIf( count( $cont ) != 3 );

                        $db = $this->getDB();
                        $op = $params['dir'] == 'descending' ? '<' : '>';
                        $prefix = $db->addQuotes( $cont[0] );
                        $title = $db->addQuotes( $cont[1] );
                        $from = intval( $cont[2] );
                        $this->addWhere(
                                "ll_lang $op $prefix OR " .
                                "(ll_lang = $prefix AND " .
                                "(ll_title $op $title OR " .
                                "(ll_title = $title AND " .
                                "ll_from $op= $from)))"
                        );
                }

                $prop = array_flip( $params['prop'] );
                $lllang = isset( $prop['lllang'] );
                $lltitle = isset( $prop['lltitle'] );

                $this->addTables( array( 'langlinks', 'page' ) );
                $this->addWhere( 'll_from = page_id' );

                $this->addFields( array( 'page_id', 'page_title', 'page_namespace', 'page_is_redirect',
                        'll_from', 'll_lang', 'll_title' ) );

                $sort = ( $params['dir'] == 'descending' ? ' DESC' : '' );
                if ( isset( $params['lang'] ) ) {
                        $this->addWhereFld( 'll_lang', $params['lang'] );
                        if ( isset( $params['title'] ) ) {
                                $this->addWhereFld( 'll_title', $params['title'] );
                                $this->addOption( 'ORDER BY', 'll_from' . $sort );
                        } else {
                                $this->addOption( 'ORDER BY', array(
                                        'll_title' . $sort,
                                        'll_from' . $sort
                                ));
                        }
                } else {
                        $this->addOption( 'ORDER BY', array(
                                'll_lang' . $sort,
                                'll_title' . $sort,
                                'll_from' . $sort
                        ));
                }

                $this->addOption( 'LIMIT', $params['limit'] + 1 );

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

                $pages = array();

                $count = 0;
                $result = $this->getResult();
                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...
                                // Continue string preserved in case the redirect query doesn't pass the limit
                                $this->setContinueEnumParameter( 'continue', "{$row->ll_lang}|{$row->ll_title}|{$row->ll_from}" );
                                break;
                        }

                        if ( !is_null( $resultPageSet ) ) {
                                $pages[] = Title::newFromRow( $row );
                        } else {
                                $entry = array( 'pageid' => $row->page_id );

                                $title = Title::makeTitle( $row->page_namespace, $row->page_title );
                                ApiQueryBase::addTitleInfo( $entry, $title );

                                if ( $row->page_is_redirect ) {
                                        $entry['redirect'] = '';
                                }

                                if ( $lllang ) {
                                        $entry['lllang'] = $row->ll_lang;
                                }

                                if ( $lltitle ) {
                                        $entry['lltitle'] = $row->ll_title;
                                }

                                $fit = $result->addValue( array( 'query', $this->getModuleName() ), null, $entry );
                                if ( !$fit ) {
                                        $this->setContinueEnumParameter( 'continue', "{$row->ll_lang}|{$row->ll_title}|{$row->ll_from}" );
                                        break;
                                }
                        }
                }

                if ( is_null( $resultPageSet ) ) {
                        $result->setIndexedTagName_internal( array( 'query', $this->getModuleName() ), 'll' );
                } else {
                        $resultPageSet->populateFromTitles( $pages );
                }
        }

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

        public function getAllowedParams() {
                return array(
                        'lang' => null,
                        'title' => null,
                        'continue' => null,
                        '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
                        ),
                        'prop' => array(
                                ApiBase::PARAM_ISMULTI => true,
                                ApiBase::PARAM_DFLT => '',
                                ApiBase::PARAM_TYPE => array(
                                        'lllang',
                                        'lltitle',
                                ),
                        ),
                        'dir' => array(
                                ApiBase::PARAM_DFLT => 'ascending',
                                ApiBase::PARAM_TYPE => array(
                                        'ascending',
                                        'descending'
                                )
                        ),
                );
        }

        public function getParamDescription() {
                return array(
                        'lang' => 'Language for the language link',
                        'title' => "Language link to search for. Must be used with {$this->getModulePrefix()}lang",
                        'continue' => 'When more results are available, use this to continue',
                        'prop' => array(
                                'Which properties to get',
                                ' lllang         - Adds the language code of the language link',
                                ' lltitle        - Adds the title of the language ink',
                        ),
                        'limit' => 'How many total pages to return',
                        'dir' => 'The direction in which to list',
                );
        }

        public function getResultProperties() {
                return array(
                        '' => array(
                                'pageid' => 'integer',
                                'ns' => 'namespace',
                                'title' => 'string',
                                'redirect' => 'boolean'
                        ),
                        'lllang' => array(
                                'lllang' => 'string'
                        ),
                        'lltitle' => array(
                                'lltitle' => 'string'
                        )
                );
        }

        public function getDescription() {
                return array( 'Find all pages that link to the given language link.',
                        'Can be used to find all links with a language code, or',
                        'all links to a title (with a given language).',
                        'Using neither parameter is effectively "All Language Links"',
                );
        }

        public function getPossibleErrors() {
                return array_merge( parent::getPossibleErrors(), array(
                        array( 'missingparam', 'lang' ),
                ) );
        }

        public function getExamples() {
                return array(
                        'api.php?action=query&list=langbacklinks&lbltitle=Test&lbllang=fr',
                        'api.php?action=query&generator=langbacklinks&glbltitle=Test&glbllang=fr&prop=info'
                );
        }
}