TYPO3 Solr: Search across multiple languages (language per core = Do not loose features like stemming)

_Introduction.md

TYPO3: A multi-language search with EXT:solr

Solr has a feature called sharding for doing search requests across multiple cores (core per language).

Pro:

• Use language individual stemming

Contra:

• Variants do not work across shards

TypoScript configuration

# de language = 0
# en language = 1
plugin.tx_solr.search.query.shard.languages = 0,1

This adds the shard parameter to the solr request:

http://localhost:8983/solr/core_de/select?shards=localhost:8983/solr/core_de,localhost:8983/solr/core_en

---

It was developed in times of TYPO3 10.4

ext_localconf.php

\ApacheSolrForTypo3\Solr\Search\SearchComponentManager::registerSearchComponent(
    'shard',
    \My\Site\Search\ShardComponent::class
);

Shard.php

<?php declare(strict_types=1);
namespace My\Site\Query\Modifier;

use ApacheSolrForTypo3\Solr\ConnectionManager;
use ApacheSolrForTypo3\Solr\Domain\Search\Query\QueryBuilder;
use ApacheSolrForTypo3\Solr\Domain\Search\Query\Query;
use ApacheSolrForTypo3\Solr\Query\Modifier\Modifier;
use ApacheSolrForTypo3\Solr\System\Configuration\TypoScriptConfiguration;
use ApacheSolrForTypo3\Solr\Util;
use TYPO3\CMS\Core\Utility\GeneralUtility;

/**
 * Adds shard query parameter
 *
 * http://localhost:8983/solr/core_de/select?shards=localhost:8983/solr/core_de,localhost:8983/solr/core_en
 */
class Shard implements Modifier
{
    /**
     * @var QueryBuilder
     */
    protected $queryBuilder;

    /**
     * @var ConnectionManager
     */
    protected $connectionManager;

    /**
     * @var TypoScriptConfiguration
     */
    protected $typoScriptConfiguration = null;

    public function __construct(QueryBuilder $builder = null)
    {
        $this->queryBuilder = $builder ?? GeneralUtility::makeInstance(QueryBuilder::class);
        $this->typoScriptConfiguration = Util::getSolrConfiguration();
        $this->connectionManager = GeneralUtility::makeInstance(ConnectionManager::class);
    }

    public function modifyQuery(Query $query): Query
    {
        $languages = GeneralUtility::trimExplode(',',
            $this->typoScriptConfiguration->getValueByPath('plugin.tx_solr.search.query.shard.languages') ?? '');
        if (count($languages) > 0) {
            $shards = [];
            foreach ($languages as $language) {
                $connection = $this->connectionManager->getConnectionByPageId($GLOBALS['TSFE']->id, (integer)$language);
                $node = $connection->getNode('read');
                $shards[] = rtrim($node->__toString(), '/');
            }
            $query->addParam('shards', implode(',', $shards));
        }

        return $query;
    }
}

ShardComponent.php

<?php declare(strict_types=1);
namespace My\Site\Search;

use My\Site\Query\Modifier\Shard;
use ApacheSolrForTypo3\Solr\Search\AbstractComponent;

class ShardComponent extends AbstractComponent
{
    public function initializeSearchComponent()
    {
        $GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['solr']['modifySearchQuery']['tx_mysite_shard'] = Shard::class;
    }
}