username-1.0.x-dev/src/EventSubscriber/ConfigCacheTag.php

<?php

namespace Drupal\username\EventSubscriber;

use Drupal\Core\Cache\CacheTagsInvalidatorInterface;
use Drupal\Core\Config\ConfigCrudEvent;
use Drupal\Core\Config\ConfigEvents;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * A subscriber invalidating cache tags when username config objects are saved.
 */
class ConfigCacheTag implements EventSubscriberInterface {

  /**
   * The cache tags invalidator.
   *
   * @var \Drupal\Core\Cache\CacheTagsInvalidatorInterface
   */
  protected $cacheTagsInvalidator;

  /**
   * Constructs a UsernameCacheTag object.
   *
   * @param \Drupal\Core\Cache\CacheTagsInvalidatorInterface $cache_tags_invalidator
   *   The cache tags invalidator.
   */
  public function __construct(CacheTagsInvalidatorInterface $cache_tags_invalidator) {
    $this->cacheTagsInvalidator = $cache_tags_invalidator;
  }

  /**
   * Invalidate cache tags when particular username config objects are saved.
   *
   * @param \Drupal\Core\Config\ConfigCrudEvent $event
   *   The Event to process.
   */
  public function onSave(ConfigCrudEvent $event) {
    // Check if the username settings object has been changed.
    if ($event->getConfig()->getName() === 'username.settings') {
      // Clear the username cache if the pattern was changed.
      username_display_name_delete_all();

      // A change to the display-name pattern must invalidate the render cache
      // since the display-name could be used anywhere.
      $this->cacheTagsInvalidator->invalidateTags(['rendered']);
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    $events[ConfigEvents::SAVE][] = ['onSave'];
    return $events;
  }

}