<?php

namespace Drupal\bar\EventSubscriber;

use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\KernelEvents;

/**
 * Foo event subscriber.
 */
class BarSubscriber implements EventSubscriberInterface {

  use StringTranslationTrait;

  /**
   * The entity type manager.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  protected $entityTypeManager;

  /**
   * Constructs event subscriber.
   *
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
   *   The entity type manager.
   */
  public function __construct(EntityTypeManagerInterface $entity_type_manager) {
    $this->entityTypeManager = $entity_type_manager;
  }

  /**
   * Kernel request event handler.
   */
  public function onKernelRequest() {
    drupal_set_message($this->t('Bar subscriber is active.'));
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() {
    return [
      KernelEvents::REQUEST => ['onKernelRequest'],
    ];
  }

}