ApiQueryLangLinks.php

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<?php
class ApiQueryLangLinks extends ApiQueryBase {

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

    public function execute() {
        if ( $this->getPageSet()->getGoodTitleCount() == 0 ) {
            return;
        }

        $params = $this->extractRequestParams();
        $prop = array_flip( (array)$params['prop'] );

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

        // Handle deprecated param
        $this->requireMaxOneParameter( $params, 'url', 'prop' );
        if ( $params['url'] ) {
            $prop = [ 'url' => 1 ];
        }

        $this->addFields( [
            'll_from',
            'll_lang',
            'll_title'
        ] );

        $this->addTables( 'langlinks' );
        $this->addWhereFld( 'll_from', array_keys( $this->getPageSet()->getGoodTitles() ) );
        if ( !is_null( $params['continue'] ) ) {
            $cont = explode( '|', $params['continue'] );
            $this->dieContinueUsageIf( count( $cont ) != 2 );
            $op = $params['dir'] == 'descending' ? '<' : '>';
            $llfrom = intval( $cont[0] );
            $lllang = $this->getDB()->addQuotes( $cont[1] );
            $this->addWhere(
                "ll_from $op $llfrom OR " .
                "(ll_from = $llfrom AND " .
                "ll_lang $op= $lllang)"
            );
        }

        // FIXME: (follow-up) To allow extensions to add to the language links, we need
        //       to load them all, add the extra links, then apply paging.
        //       Should not be terrible, it's not going to be more than a few hundred links.

        // Note that, since (ll_from, ll_lang) is a unique key, we don't need
        // to sort by ll_title to ensure deterministic ordering.
        $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 {
            // Don't order by ll_from if it's constant in the WHERE clause
            if ( count( $this->getPageSet()->getGoodTitles() ) == 1 ) {
                $this->addOption( 'ORDER BY', 'll_lang' . $sort );
            } else {
                $this->addOption( 'ORDER BY', [
                    'll_from' . $sort,
                    'll_lang' . $sort
                ] );
            }
        }

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

        $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->ll_from}|{$row->ll_lang}" );
                break;
            }
            $entry = [ 'lang' => $row->ll_lang ];
            if ( isset( $prop['url'] ) ) {
                $title = Title::newFromText( "{$row->ll_lang}:{$row->ll_title}" );
                if ( $title ) {
                    $entry['url'] = wfExpandUrl( $title->getFullURL(), PROTO_CURRENT );
                }
            }
            if ( isset( $prop['langname'] ) ) {
                $entry['langname'] = Language::fetchLanguageName( $row->ll_lang, $params['inlanguagecode'] );
            }
            if ( isset( $prop['autonym'] ) ) {
                $entry['autonym'] = Language::fetchLanguageName( $row->ll_lang );
            }
            ApiResult::setContentValue( $entry, 'title', $row->ll_title );
            $fit = $this->addPageSubItem( $row->ll_from, $entry );
            if ( !$fit ) {
                $this->setContinueEnumParameter( 'continue', "{$row->ll_from}|{$row->ll_lang}" );
                break;
            }
        }
    }

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

    public function getAllowedParams() {
        global $wgContLang;
        return [
            'prop' => [
                ApiBase::PARAM_ISMULTI => true,
                ApiBase::PARAM_TYPE => [
                    'url',
                    'langname',
                    'autonym',
                ],
                ApiBase::PARAM_HELP_MSG_PER_VALUE => [],
            ],
            'lang' => null,
            'title' => null,
            'dir' => [
                ApiBase::PARAM_DFLT => 'ascending',
                ApiBase::PARAM_TYPE => [
                    'ascending',
                    'descending'
                ]
            ],
            'inlanguagecode' => $wgContLang->getCode(),
            'limit' => [
                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' => [
                ApiBase::PARAM_HELP_MSG => 'api-help-param-continue',
            ],
            'url' => [
                ApiBase::PARAM_DFLT => false,
                ApiBase::PARAM_DEPRECATED => true,
            ],
        ];
    }

    protected function getExamplesMessages() {
        return [
            'action=query&prop=langlinks&titles=Main%20Page&redirects='
                => 'apihelp-query+langlinks-example-simple',
        ];
    }

    public function getHelpUrls() {
        return 'https://www.mediawiki.org/wiki/API:Langlinks';
    }
}