ApiOpenSearch.php

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<?php
use MediaWiki\MediaWikiServices;

class ApiOpenSearch extends ApiBase {

    private $format = null;
    private $fm = null;

    protected function getFormat() {
        if ( $this->format === null ) {
            $params = $this->extractRequestParams();
            $format = $params['format'];

            $allowedParams = $this->getAllowedParams();
            if ( !in_array( $format, $allowedParams['format'][ApiBase::PARAM_TYPE] ) ) {
                $format = $allowedParams['format'][ApiBase::PARAM_DFLT];
            }

            if ( substr( $format, -2 ) === 'fm' ) {
                $this->format = substr( $format, 0, -2 );
                $this->fm = 'fm';
            } else {
                $this->format = $format;
                $this->fm = '';
            }
        }
        return $this->format;
    }

    public function getCustomPrinter() {
        switch ( $this->getFormat() ) {
            case 'json':
                return new ApiOpenSearchFormatJson(
                    $this->getMain(), $this->fm, $this->getParameter( 'warningsaserror' )
                );

            case 'xml':
                $printer = $this->getMain()->createPrinterByName( 'xml' . $this->fm );
                $printer->setRootElement( 'SearchSuggestion' );
                return $printer;

            default:
                ApiBase::dieDebug( __METHOD__, "Unsupported format '{$this->getFormat()}'" );
        }
    }

    public function execute() {
        $params = $this->extractRequestParams();
        $search = $params['search'];
        $limit = $params['limit'];
        $namespaces = $params['namespace'];
        $suggest = $params['suggest'];

        if ( $params['redirects'] === null ) {
            // Backwards compatibility, don't resolve for JSON.
            $resolveRedir = $this->getFormat() !== 'json';
        } else {
            $resolveRedir = $params['redirects'] === 'resolve';
        }

        $results = [];

        if ( !$suggest || $this->getConfig()->get( 'EnableOpenSearchSuggest' ) ) {
            // Open search results may be stored for a very long time
            $this->getMain()->setCacheMaxAge( $this->getConfig()->get( 'SearchSuggestCacheExpiry' ) );
            $this->getMain()->setCacheMode( 'public' );
            $this->search( $search, $limit, $namespaces, $resolveRedir, $results );

            // Allow hooks to populate extracts and images
            Hooks::run( 'ApiOpenSearchSuggest', [ &$results ] );

            // Trim extracts, if necessary
            $length = $this->getConfig()->get( 'OpenSearchDescriptionLength' );
            foreach ( $results as &$r ) {
                if ( is_string( $r['extract'] ) && !$r['extract trimmed'] ) {
                    $r['extract'] = self::trimExtract( $r['extract'], $length );
                }
            }
        }

        // Populate result object
        $this->populateResult( $search, $results );
    }

    protected function search( $search, $limit, $namespaces, $resolveRedir, &$results ) {
        $searchEngine = MediaWikiServices::getInstance()->newSearchEngine();
        $searchEngine->setLimitOffset( $limit );
        $searchEngine->setNamespaces( $namespaces );
        $titles = $searchEngine->extractTitles( $searchEngine->completionSearchWithVariants( $search ) );

        if ( !$titles ) {
            return;
        }

        // Special pages need unique integer ids in the return list, so we just
        // assign them negative numbers because those won't clash with the
        // always positive articleIds that non-special pages get.
        $nextSpecialPageId = -1;

        if ( $resolveRedir ) {
            // Query for redirects
            $redirects = [];
            $lb = new LinkBatch( $titles );
            if ( !$lb->isEmpty() ) {
                $db = $this->getDB();
                $res = $db->select(
                    [ 'page', 'redirect' ],
                    [ 'page_namespace', 'page_title', 'rd_namespace', 'rd_title' ],
                    [
                        'rd_from = page_id',
                        'rd_interwiki IS NULL OR rd_interwiki = ' . $db->addQuotes( '' ),
                        $lb->constructSet( 'page', $db ),
                    ],
                    __METHOD__
                );
                foreach ( $res as $row ) {
                    $redirects[$row->page_namespace][$row->page_title] =
                        [ $row->rd_namespace, $row->rd_title ];
                }
            }

            // Bypass any redirects
            $seen = [];
            foreach ( $titles as $title ) {
                $ns = $title->getNamespace();
                $dbkey = $title->getDBkey();
                $from = null;
                if ( isset( $redirects[$ns][$dbkey] ) ) {
                    list( $ns, $dbkey ) = $redirects[$ns][$dbkey];
                    $from = $title;
                    $title = Title::makeTitle( $ns, $dbkey );
                }
                if ( !isset( $seen[$ns][$dbkey] ) ) {
                    $seen[$ns][$dbkey] = true;
                    $resultId = $title->getArticleID();
                    if ( $resultId === 0 ) {
                        $resultId = $nextSpecialPageId;
                        $nextSpecialPageId -= 1;
                    }
                    $results[$resultId] = [
                        'title' => $title,
                        'redirect from' => $from,
                        'extract' => false,
                        'extract trimmed' => false,
                        'image' => false,
                        'url' => wfExpandUrl( $title->getFullURL(), PROTO_CURRENT ),
                    ];
                }
            }
        } else {
            foreach ( $titles as $title ) {
                $resultId = $title->getArticleID();
                if ( $resultId === 0 ) {
                    $resultId = $nextSpecialPageId;
                    $nextSpecialPageId -= 1;
                }
                $results[$resultId] = [
                    'title' => $title,
                    'redirect from' => null,
                    'extract' => false,
                    'extract trimmed' => false,
                    'image' => false,
                    'url' => wfExpandUrl( $title->getFullURL(), PROTO_CURRENT ),
                ];
            }
        }
    }

    protected function populateResult( $search, &$results ) {
        $result = $this->getResult();

        switch ( $this->getFormat() ) {
            case 'json':
                // http://www.opensearch.org/Specifications/OpenSearch/Extensions/Suggestions/1.1
                $result->addArrayType( null, 'array' );
                $result->addValue( null, 0, strval( $search ) );
                $terms = [];
                $descriptions = [];
                $urls = [];
                foreach ( $results as $r ) {
                    $terms[] = $r['title']->getPrefixedText();
                    $descriptions[] = strval( $r['extract'] );
                    $urls[] = $r['url'];
                }
                $result->addValue( null, 1, $terms );
                $result->addValue( null, 2, $descriptions );
                $result->addValue( null, 3, $urls );
                break;

            case 'xml':
                // http://msdn.microsoft.com/en-us/library/cc891508%28v=vs.85%29.aspx
                $imageKeys = [
                    'source' => true,
                    'alt' => true,
                    'width' => true,
                    'height' => true,
                    'align' => true,
                ];
                $items = [];
                foreach ( $results as $r ) {
                    $item = [
                        'Text' => $r['title']->getPrefixedText(),
                        'Url' => $r['url'],
                    ];
                    if ( is_string( $r['extract'] ) && $r['extract'] !== '' ) {
                        $item['Description'] = $r['extract'];
                    }
                    if ( is_array( $r['image'] ) && isset( $r['image']['source'] ) ) {
                        $item['Image'] = array_intersect_key( $r['image'], $imageKeys );
                    }
                    ApiResult::setSubelementsList( $item, array_keys( $item ) );
                    $items[] = $item;
                }
                ApiResult::setIndexedTagName( $items, 'Item' );
                $result->addValue( null, 'version', '2.0' );
                $result->addValue( null, 'xmlns', 'http://opensearch.org/searchsuggest2' );
                $result->addValue( null, 'Query', strval( $search ) );
                $result->addSubelementsList( null, 'Query' );
                $result->addValue( null, 'Section', $items );
                break;

            default:
                ApiBase::dieDebug( __METHOD__, "Unsupported format '{$this->getFormat()}'" );
        }
    }

    public function getAllowedParams() {
        return [
            'search' => null,
            'limit' => [
                ApiBase::PARAM_DFLT => $this->getConfig()->get( 'OpenSearchDefaultLimit' ),
                ApiBase::PARAM_TYPE => 'limit',
                ApiBase::PARAM_MIN => 1,
                ApiBase::PARAM_MAX => 100,
                ApiBase::PARAM_MAX2 => 100
            ],
            'namespace' => [
                ApiBase::PARAM_DFLT => NS_MAIN,
                ApiBase::PARAM_TYPE => 'namespace',
                ApiBase::PARAM_ISMULTI => true
            ],
            'suggest' => false,
            'redirects' => [
                ApiBase::PARAM_TYPE => [ 'return', 'resolve' ],
            ],
            'format' => [
                ApiBase::PARAM_DFLT => 'json',
                ApiBase::PARAM_TYPE => [ 'json', 'jsonfm', 'xml', 'xmlfm' ],
            ],
            'warningsaserror' => false,
        ];
    }

    protected function getExamplesMessages() {
        return [
            'action=opensearch&search=Te'
                => 'apihelp-opensearch-example-te',
        ];
    }

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

    public static function trimExtract( $text, $length ) {
        static $regex = null;

        if ( $regex === null ) {
            $endchars = [
                '([^\d])\.\s', '\!\s', '\?\s', // regular ASCII
                '。', // full-width ideographic full-stop
                '．', '！', '？', // double-width roman forms
                '｡', // half-width ideographic full stop
            ];
            $endgroup = implode( '|', $endchars );
            $end = "(?:$endgroup)";
            $sentence = ".{{$length},}?$end+";
            $regex = "/^($sentence)/u";
        }

        $matches = [];
        if ( preg_match( $regex, $text, $matches ) ) {
            return trim( $matches[1] );
        } else {
            // Just return the first line
            return trim( explode( "\n", $text )[0] );
        }
    }

    public static function getOpenSearchTemplate( $type ) {
        $config = MediaWikiServices::getInstance()->getSearchEngineConfig();
        $template = $config->getConfig()->get( 'OpenSearchTemplate' );

        if ( $template && $type === 'application/x-suggestions+json' ) {
            return $template;
        }

        $ns = implode( '|', $config->defaultNamespaces() );
        if ( !$ns ) {
            $ns = '0';
        }

        switch ( $type ) {
            case 'application/x-suggestions+json':
                return $config->getConfig()->get( 'CanonicalServer' ) . wfScript( 'api' )
                    . '?action=opensearch&search={searchTerms}&namespace=' . $ns;

            case 'application/x-suggestions+xml':
                return $config->getConfig()->get( 'CanonicalServer' ) . wfScript( 'api' )
                    . '?action=opensearch&format=xml&search={searchTerms}&namespace=' . $ns;

            default:
                throw new MWException( __METHOD__ . ": Unknown type '$type'" );
        }
    }
}

class ApiOpenSearchFormatJson extends ApiFormatJson {
    private $warningsAsError = false;

    public function __construct( ApiMain $main, $fm, $warningsAsError ) {
        parent::__construct( $main, "json$fm" );
        $this->warningsAsError = $warningsAsError;
    }

    public function execute() {
        if ( !$this->getResult()->getResultData( 'error' ) ) {
            $result = $this->getResult();

            // Ignore warnings or treat as errors, as requested
            $warnings = $result->removeValue( 'warnings', null );
            if ( $this->warningsAsError && $warnings ) {
                $this->dieUsage(
                    'Warnings cannot be represented in OpenSearch JSON format', 'warnings', 0,
                    [ 'warnings' => $warnings ]
                );
            }

            // Ignore any other unexpected keys (e.g. from $wgDebugToolbar)
            $remove = array_keys( array_diff_key(
                $result->getResultData(),
                [ 0 => 'search', 1 => 'terms', 2 => 'descriptions', 3 => 'urls' ]
            ) );
            foreach ( $remove as $key ) {
                $result->removeValue( $key, null );
            }
        }

        parent::execute();
    }
}