How to Alter Entity Autocomplete Results in Drupal 8

Sometimes you might want to display additional data in the autocomplete results, for instance add content language next to the title, or display entity type or any other related data. In this blog post I will demonstrate how to alter suggestions in autocomplete fields in Drupal 8. The project is available for download from github, see the link at the bottom of the page.

Link autocomplete results

Here is the module structure I will be using:

alter_entity_autocomplete/
  - alter_entity_autocomplete.info.yml
  - alter_entity_autocomplete.services.yml
  - src/
    - EntityAutocompleteMatcher.php
    - Controller/
      - EntityAutocompleteController.php
    - Routing/
      - AutocompleteRouteSubscriber.php

Contents of the alter_entity_autocomplete.info.yml file:

name: Alter Entity Autocomplete
description: The module alters entity autocomplete suggestion list.
type: module
core: 8.x

Contents of the alter_entity_autocomplete.services.yml file:

services:

  alter_entity_autocomplete.route_subscriber:
    class: Drupal\alter_entity_autocomplete\Routing\AutocompleteRouteSubscriber
    tags:
      - { name: event_subscriber }

  alter_entity_autocomplete.autocomplete_matcher:
    class: Drupal\alter_entity_autocomplete\EntityAutocompleteMatcher
    arguments: ['@plugin.manager.entity_reference_selection']

Contents of the src/EntityAutocompleteMatcher.php file. This is the file where you would change the output of the sugesstions/autocomplete results:

<?php

namespace Drupal\alter_entity_autocomplete;

use Drupal\Component\Utility\Html;
use Drupal\Component\Utility\Tags;

class EntityAutocompleteMatcher extends \Drupal\Core\Entity\EntityAutocompleteMatcher {

  /**
   * Gets matched labels based on a given search string.
   */
  public function getMatches($target_type, $selection_handler, $selection_settings, $string = '') {

    $matches = [];

    $options = [
      'target_type'      => $target_type,
      'handler'          => $selection_handler,
      'handler_settings' => $selection_settings,
    ];

    $handler = $this->selectionManager->getInstance($options);

    if (isset($string)) {
      // Get an array of matching entities.
      $match_operator = !empty($selection_settings['match_operator']) ? $selection_settings['match_operator'] : 'CONTAINS';
      $entity_labels = $handler->getReferenceableEntities($string, $match_operator, 10);

      // Loop through the entities and convert them into autocomplete output.
      foreach ($entity_labels as $values) {
        foreach ($values as $entity_id => $label) {

          $entity = \Drupal::entityTypeManager()->getStorage($target_type)->load($entity_id);
          $entity = \Drupal::entityManager()->getTranslationFromContext($entity);

          $type = !empty($entity->type->entity) ? $entity->type->entity->label() : $entity->bundle();
          $status = '';
          if ($entity->getEntityType()->id() == 'node') {
            $status = ($entity->isPublished()) ? ", Published" : ", Unpublished";
          }

          $key = $label . ' (' . $entity_id . ')';
          // Strip things like starting/trailing white spaces, line breaks and tags.
          $key = preg_replace('/\s\s+/', ' ', str_replace("\n", '', trim(Html::decodeEntities(strip_tags($key)))));
          // Names containing commas or quotes must be wrapped in quotes.
          $key = Tags::encode($key);
          $label = $label . ' (' . $entity_id . ') [' . $type . $status . ']';
          $matches[] = ['value' => $key, 'label' => $label];
        }
      }
    }

    return $matches;
  }

}

Contents of the src/Controller/EntityAutocompleteController.php file:

<?php

namespace Drupal\alter_entity_autocomplete\Controller;

use Drupal\Core\KeyValueStore\KeyValueStoreInterface;
use Drupal\alter_entity_autocomplete\EntityAutocompleteMatcher;
use Symfony\Component\DependencyInjection\ContainerInterface;

class EntityAutocompleteController extends \Drupal\system\Controller\EntityAutocompleteController {

  /**
   * The autocomplete matcher for entity references.
   */
  protected $matcher;

  /**
   * {@inheritdoc}
   */
  public function __construct(EntityAutocompleteMatcher $matcher, KeyValueStoreInterface $key_value) {
    $this->matcher = $matcher;
    $this->keyValue = $key_value;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container) {
    return new static(
      $container->get('alter_entity_autocomplete.autocomplete_matcher'),
      $container->get('keyvalue')->get('entity_autocomplete')
    );
  }

}

Here is contents of the src/Routing/AutocompleteRouteSubscriber.php file:

<?php

namespace Drupal\alter_entity_autocomplete\Routing;

use Drupal\Core\Routing\RouteSubscriberBase;
use Symfony\Component\Routing\RouteCollection;

class AutocompleteRouteSubscriber extends RouteSubscriberBase {

  public function alterRoutes(RouteCollection $collection) {
    if ($route = $collection->get('system.entity_autocomplete')) {
      $route->setDefault('_controller', '\Drupal\alter_entity_autocomplete\Controller\EntityAutocompleteController::handleAutocomplete');
    }
  }

}

This module was developed with help of my co-workers and I hope you will find this useful.

Download from Github