AccessDeniedSubscriber::onException

public AccessDeniedSubscriber::onException(GetResponseForExceptionEvent $event)

public function onException(GetResponseForExceptionEvent $event) {
  $exception = $event->getException();
  if ($exception instanceof AccessDeniedHttpException) {
    $route_name = RouteMatch::createFromRequest($event->getRequest())->getRouteName();
    if ($this->account->isAuthenticated()) {
      switch ($route_name) {
        case 'user.login':
          // Redirect an authenticated user to the profile page.
          $event->setResponse($this->redirect('entity.user.canonical', ['user' => $this->account->id()]));
          break;

        case 'user.register':
          // Redirect an authenticated user to the profile form.
          $event->setResponse($this->redirect('entity.user.edit_form', ['user' => $this->account->id()]));
          break;
      }
    }
    elseif ($route_name === 'user.page') {
      $event->setResponse($this->redirect('user.login'));
    }
  }
}