Add event subscriber.

advanced_search.services.yml

@@ -0,0 +1,4 @@
+services:
+  Drupal\advanced_search\EventSubscriber\PostConvertedQueryEventSubscriber:
+    tags:
+      - { name: 'event_subscriber' }

src/EventSubscriber/PostConvertedQueryEventSubscriber.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Drupal\advanced_search\EventSubscriber;
+
+use Drupal\advanced_search\AdvancedSearchQuery;
+use Drupal\search_api_solr\Event\SearchAPISolrEvents;
+use Drupal\search_api_solr\Event\PostConvertedQueryEvent;
+
+class PostConvertedQueryEventSubscriber extends EventSubscriberInterface() {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function getSubscribedEvents() {
+    $events[SearchAPISolrEvents::POST_CONVERT_QUERY][] = ['alter'];
+
+    return $events;
+
+  }
+
+  /**
+   * Alter the query.
+   */
+  public function alter(PostConvertedQueryEvent $event) {
+    $search_api_query = $event->getSearchApiQuery();
+    $solarium_query = $event->getSolariumQuery();
+    $advanced_search_query = new AdvancedSearchQuery();
+    $advanced_search_query->alterQuery(\Drupal::request(), $solarium_query, $search_api_query);
+  }
+
+}