.. _extending_solr:

Extending Solr indexation
-------------------------

How to index page blocks contents
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If all your text content is written in *block nodes* instead of reachable *pages*, you should index them
into your page Solr documents to improve your search engine relevancy.

You can use the ``NodesSourcesIndexingEvent::class`` event to enhance your node indexing data before
it’s persisted into *Solr* engine (especially ``collection_txt`` field):

.. code-block:: php

    <?php

    declare(strict_types=1);

    namespace App\EventSubscriber;

    use RZ\Roadiz\CoreBundle\Api\TreeWalker\AutoChildrenNodeSourceWalker;
    use RZ\Roadiz\CoreBundle\Entity\NodesSources;
    use RZ\Roadiz\CoreBundle\Event\NodesSources\NodesSourcesIndexingEvent;
    use RZ\Roadiz\CoreBundle\SearchEngine\SolariumFactoryInterface;
    use RZ\TreeWalker\WalkerContextInterface;
    use RZ\TreeWalker\WalkerInterface;
    use Symfony\Component\EventDispatcher\EventSubscriberInterface;

    /**
     * Index sub nodes content into any reachable node-source.
     */
    final class NodeSourceIndexingEventSubscriber implements EventSubscriberInterface
    {
        private WalkerContextInterface $walkerContext;
        private SolariumFactoryInterface $solariumFactory;
        private int $maxLevel;

        /**
         * @param WalkerContextInterface $walkerContext
         * @param SolariumFactoryInterface $solariumFactory
         * @param int $maxLevel
         */
        public function __construct(
            WalkerContextInterface $walkerContext,
            SolariumFactoryInterface $solariumFactory,
            int $maxLevel = 5
        ) {
            $this->walkerContext = $walkerContext;
            $this->solariumFactory = $solariumFactory;
            $this->maxLevel = $maxLevel;
        }

        /**
         * @inheritDoc
         */
        public static function getSubscribedEvents(): array
        {
            return [
                NodesSourcesIndexingEvent::class => ['onIndexing'],
            ];
        }

        public function onIndexing(NodesSourcesIndexingEvent $event): void
        {
            $nodeSource = $event->getNodeSource();

            if (null !== $nodeSource->getNode() && $nodeSource->isReachable() && !$event->isSubResource()) {
                $assoc = $event->getAssociations();

                $blockWalker = AutoChildrenNodeSourceWalker::build(
                    $nodeSource,
                    $this->walkerContext,
                    $this->maxLevel
                );

                // Need a locale field
                $locale = $nodeSource->getTranslation()->getLocale();
                $lang = \Locale::getPrimaryLanguage($locale) ?? 'fr';

                foreach ($blockWalker->getChildren() as $subWalker) {
                    $this->walkAndIndex($subWalker, $assoc, $lang);
                }

                $event->setAssociations($assoc);
            }
        }

        /**
         * @param WalkerInterface $walker
         * @param array $assoc
         * @param string $locale
         * @throws \Exception
         */
        protected function walkAndIndex(WalkerInterface $walker, array &$assoc, string $locale): void
        {
            $item = $walker->getItem();
            if ($item instanceof NodesSources) {
                $solarium = $this->solariumFactory->createWithNodesSources($walker->getItem());
                // Fetch all fields array association AS sub-resources (i.e. do not index their title)
                $childAssoc = $solarium->getFieldsAssoc(true);
                $assoc['collection_txt'] = array_filter(array_merge(
                    $assoc['collection_txt'],
                    $childAssoc['collection_txt']
                ));
                if (!empty($childAssoc['collection_txt_' . $locale])) {
                    $assoc['collection_txt_' . $locale] .= PHP_EOL . $childAssoc['collection_txt_' . $locale];
                }
            }
            if ($walker->count() > 0) {
                foreach ($walker->getChildren() as $subWalker) {
                    $this->walkAndIndex($subWalker, $assoc, $locale);
                }
            }
        }
    }