Call setResponse() to set the response that will be returned for the
current request. The propagation of this event is stopped as soon as a
response is set.
use Symfony\Component\HttpKernel\Event\GetResponseEvent; class AuthenticationListener { public function onKernelRequest(GetResponseEvent $event) { // get the request from the event $request = $event->getRequest(); // check if the user is authenticated if (!$request->isAuthenticated()) { // deny access $response = new Response('Access Denied', 403); $event->setResponse($response); } } }This code registers an event listener that listens for the GetResponseEvent. When this event is triggered, the onKernelRequest method is called. The code then gets the request associated with the event and checks if the user is authenticated. If the user is not authenticated, the code creates a new response with a "403 Access Denied" status code and sets the response on the event. This example uses the Symfony HttpKernel component.