wikimedia/mediawiki-extensions-CirrusSearch

<?php

namespace CirrusSearch\Query;

use CirrusSearch\CrossSearchStrategy;
use CirrusSearch\Parser\AST\KeywordFeatureNode;
use CirrusSearch\Query\Builder\QueryBuildingContext;
use CirrusSearch\Search\Rescore\ByKeywordTemplateBoostFunction;
use CirrusSearch\Search\SearchContext;
use CirrusSearch\WarningCollector;

/**
 * Handles the boost-templates keyword in full text search. Allows user
 * to specify a percentage to increase or decrease a search result by based
 * on the templates included in the page. Templates can be specified with
 * spaces or underscores. Multiple templates can be specified. Any value
 * including a space must be quoted.
 *
 * Examples:
 *  boost-templates:Main_article|250%
 *  boost-templates:"Featured sound|150%"
 *  boost-templates:"Main_article|250% List_of_lists|10%"
 */
class BoostTemplatesFeature extends SimpleKeywordFeature implements BoostFunctionFeature {
    /**
     * @return string[]
     */
    protected function getKeywords() {
        return [ 'boost-templates' ];
    }

    /**
     * @param KeywordFeatureNode $node
     * @return CrossSearchStrategy
     */
    public function getCrossSearchStrategy( KeywordFeatureNode $node ) {
        return CrossSearchStrategy::allWikisStrategy();
    }

    /**
     * @param SearchContext $context
     * @param string $key The keyword
     * @param string $value The value attached to the keyword with quotes stripped
     * @param string $quotedValue The original value in the search string, including quotes if used
     * @param bool $negated Is the search negated? Not used to generate the returned AbstractQuery,
     *  that will be negated as necessary. Used for any other building/context necessary.
     * @return array Two element array, first an AbstractQuery or null to apply to the
     *  query. Second a boolean indicating if the quotedValue should be kept in the search
     *  string.
     */
    protected function doApply( SearchContext $context, $key, $value, $quotedValue, $negated ) {
        $context->addCustomRescoreComponent(
            $this->buildBoostFunction( [ 'boost-templates' => self::parseBoostTemplates( $value ) ] )
        );

        return [ null, false ];
    }

    /**
     * Parse boosted templates.  Parse failures silently return no boosted templates.
     * Matches a template name followed by a | then a positive integer followed by a %.
     * Multiple templates can be specified separated by a space.
     *
     * Examples:
     *   Featured_article|150%
     *   List of lists|10% Featured_sound|200%
     *
     * @param string $text text representation of boosted templates
     * @return float[] map of boosted templates (key is the template, value is a float).
     */
    public static function parseBoostTemplates( $text ) {
        $boostTemplates = [];
        $templateMatches = [];
        if ( preg_match_all( '/([^|]+)\|(\d+)% ?/', $text, $templateMatches, PREG_SET_ORDER ) ) {
            foreach ( $templateMatches as $templateMatch ) {
                // templates field is populated with Title::getPrefixedText
                // which will replace _ to ' '. We should do the same here.
                $template = strtr( $templateMatch[ 1 ], '_', ' ' );
                $boostTemplates[ $template ] = floatval( $templateMatch[ 2 ] ) / 100;
            }
        }
        return $boostTemplates;
    }

    /**
     * @param string $key
     * @param string $value
     * @param string $quotedValue
     * @param string $valueDelimiter
     * @param string $suffix
     * @param WarningCollector $warningCollector
     * @return array|false|float[]|null
     */
    public function parseValue( $key, $value, $quotedValue, $valueDelimiter, $suffix, WarningCollector $warningCollector ) {
        return [ 'boost-templates' => self::parseBoostTemplates( $value ) ];
    }

    /**
     * @param KeywordFeatureNode $node
     * @param QueryBuildingContext $context
     * @return \CirrusSearch\Search\Rescore\BoostFunctionBuilder|null
     */
    public function getBoostFunctionBuilder( KeywordFeatureNode $node, QueryBuildingContext $context ) {
        return $this->buildBoostFunction( $node->getParsedValue() );
    }

    /**
     * @param array $parsedValue
     * @return ByKeywordTemplateBoostFunction
     */
    private function buildBoostFunction( array $parsedValue ) {
        return new ByKeywordTemplateBoostFunction( $parsedValue['boost-templates'] );
    }
}