ezcontent-8.x-dev/modules/ezcontent_node/modules/ezcontent_smart_article/src/EventSubscriber/SmartArticleCheckSubscriptionEvent.php

<?php

namespace Drupal\ezcontent_smart_article\EventSubscriber;

use Symfony\Contracts\EventDispatcher\Event;
use Drupal\Core\Config\ConfigFactoryInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\KernelEvents;

/**
 * Checks subscriptions for smart_article API keys.
 */
class SmartArticleCheckSubscriptionEvent implements EventSubscriberInterface {

  /**
   * The config object.
   *
   * @var \Drupal\Core\Config\ConfigFactoryInterface
   */
  protected $config;

  /**
   * Constructs this factory object.
   *
   * @param \Drupal\Core\Config\ConfigFactoryInterface $configFactory
   *   The config factory.
   */
  public function __construct(ConfigFactoryInterface $configFactory) {
    $this->config = $configFactory->get('ezcontent_smart_article.settings');
  }

  /**
   * Returns an array of event names this subscriber wants to listen to.
   *
   * The array keys are event names and the value can be:
   *
   *  * The method name to call (priority defaults to 0)
   *  * An array composed of the method name to call and the priority
   *  * An array of arrays composed of the method names to call and respective
   *    priorities, or 0 if unset
   *
   * For instance:
   *
   *  * ['eventName' => 'methodName']
   *  * ['eventName' => ['methodName', $priority]]
   *  * ['eventName' => [['methodName1', $priority], ['methodName2']]]
   *
   * @return array
   *   The event names to listen to.
   */
  public static function getSubscribedEvents() {
    // Implement getSubscribedEvents() method.
    $events[KernelEvents::REQUEST][] = ['checkSubscription', 30];
    return $events;
  }

  /**
   * Check if user has subscription, if not redirect to subscription page.
   */
  public function checkSubscription(Event $event) {
    if (!$event->getRequest()->isXmlHttpRequest() && $event->getRequest()
      ->getRequestUri() == "/node/add/smart_article") {
      if (empty($this->config->get('summary_generator_api_url'))) {
        // @todo: Uncomment the below line to redirect it
        // to subscription page once its design is ready.
        // $event->setResponse(new RedirectResponse(\Drupal::
        // url('ezcontent_smart_article.get_subscription'), 301, []));
      }

    }
  }

}