wikimedia/mediawiki-extensions-CirrusSearch

<?php

namespace CirrusSearch\Fallbacks;

use CirrusSearch\Parser\QueryStringRegex\SearchQueryParseException;
use CirrusSearch\Search\CirrusSearchResultSet;
use CirrusSearch\Search\SearchQuery;
use CirrusSearch\Search\SearchQueryBuilder;
use CirrusSearch\Searcher;
use Elastica\ResultSet as ElasticaResultSet;
use HtmlArmor;
use ISearchResultSet;
use MediaWiki\Logger\LoggerFactory;

trait FallbackMethodTrait {

    /**
     * Check the number of total hits stored in $resultSet
     * and return true if it's greater or equals than $threshold
     * NOTE: inter wiki results are check
     *
     * @param CirrusSearchResultSet $resultSet
     * @param int $threshold (defaults to 1).
     *
     * @see \ISearchResultSet::getInterwikiResults()
     * @see \ISearchResultSet::SECONDARY_RESULTS
     * @return bool
     */
    public function resultsThreshold( CirrusSearchResultSet $resultSet, $threshold = 1 ) {
        if ( $resultSet->getTotalHits() >= $threshold ) {
            return true;
        }
        foreach ( $resultSet->getInterwikiResults( ISearchResultSet::SECONDARY_RESULTS ) as $resultSet ) {
            if ( $resultSet->getTotalHits() >= $threshold ) {
                return true;
            }
        }
        return false;
    }

    /**
     * Check if any result in the response is fully highlighted on the title field
     * @param \Elastica\ResultSet $results
     * @return bool true if a result has its title fully highlighted
     */
    public function resultContainsFullyHighlightedMatch( ElasticaResultSet $results ) {
        foreach ( $results as $result ) {
            $highlights = $result->getHighlights();
            // TODO: Should we check redirects as well?
            // If the whole string is highlighted then return true
            $regex = '/' . Searcher::HIGHLIGHT_PRE_MARKER . '.*?' . Searcher::HIGHLIGHT_POST_MARKER . '/';
            if ( isset( $highlights[ 'title' ] ) &&
                 !trim( preg_replace( $regex, '', $highlights[ 'title' ][ 0 ] ) ) ) {
                return true;
            }
        }
        return false;
    }

    /**
     * If all conditions are met execute a search query using the $suggestedQuery and returns its results.
     * Conditions are:
     *  - SearchQuery::isAllowRewrite() must be true on the original query
     *  - The original query must be a simple bag of words
     *  - FallbackRunnerContext::costlyCallAllowed() must be true
     *  - number of displayable results must not exceed $resultsThreshold
     *
     * @param FallbackRunnerContext $context
     * @param SearchQuery $originalQuery
     * @param string $suggestedQuery
     * @param HtmlArmor|string|null $suggestedQuerySnippet
     * @param int $resultsThreshold
     * @return FallbackStatus
     * @throws \CirrusSearch\Parser\ParsedQueryClassifierException
     * @see SearchQuery::isAllowRewrite()
     * @see FallbackRunnerContext::costlyCallAllowed()
     * @see FallbackMethodTrait::resultsThreshold()
     */
    public function maybeSearchAndRewrite(
        FallbackRunnerContext $context,
        SearchQuery $originalQuery,
        string $suggestedQuery,
        $suggestedQuerySnippet = null,
        int $resultsThreshold = 1
    ): FallbackStatus {
        $previousSet = $context->getPreviousResultSet();
        if ( !$originalQuery->isAllowRewrite()
             || !$context->costlyCallAllowed()
             || $this->resultsThreshold( $previousSet, $resultsThreshold )
        ) {
            // Only provide the suggestion, not the results of the suggestion.
            return FallbackStatus::suggestQuery( $suggestedQuery, $suggestedQuerySnippet );
        }

        try {
            $rewrittenQuery = SearchQueryBuilder::forRewrittenQuery( $originalQuery, $suggestedQuery,
                    $context->getNamespacePrefixParser(), $context->getCirrusSearchHookRunner() )->build();
        } catch ( SearchQueryParseException $e ) {
            LoggerFactory::getInstance( 'CirrusSearch' )
                ->warning( "Cannot parse rewritten query", [ 'exception' => $e ] );
            // Suggest the user submits the suggested query directly
            return FallbackStatus::suggestQuery( $suggestedQuery, $suggestedQuerySnippet );
        }
        $searcher = $context->makeSearcher( $rewrittenQuery );
        $status = $searcher->search( $rewrittenQuery );
        if ( $status->isOK() && $status->getValue() instanceof CirrusSearchResultSet ) {
            /**
             * @var CirrusSearchResultSet $newResults
             */
            $newResults = $status->getValue();
            return FallbackStatus::replaceLocalResults( $newResults, $suggestedQuery, $suggestedQuerySnippet );
        } else {
            // The suggested query returned no results, there doesn't seem to be any benefit
            // to sugesting it to the user.
            return FallbackStatus::noSuggestion();
        }
    }
}