use Symfony\Component\HttpKernel\KernelEvents;
use Symfony\Component\HttpKernel\Event;
use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\RedirectResponse;
use Drupal\Core\Url;
use Symfony\Component\HttpKernel\Event\RequestEvent;

/**
 * Provides a MyModuleSubscriber.
 */
class BootAccesFlag implements EventSubscriberInterface {

  /**
   * // only if KernelEvents::REQUEST !!!
   * @see Symfony\Component\HttpKernel\KernelEvents for details
   *
   * @param Symfony\Component\HttpKernel\Event\GetResponseEvent $event
   *   The Event to process.
   */
  public function MyModuleLoad(GetResponseEvent $event) {
    // @todo remove this debug code
        if (Условие) {
      $url = Url::fromRoute('node.add_page')->toString();
      $response = new RedirectResponse($url, 301);
      $event->setResponse($response);

          }
}

  /**
   * {@inheritdoc}
   */
  static function getSubscribedEvents() {
    $events[KernelEvents::REQUEST][] = array('MyModuleLoad', 250);
    return $events;
  }
}