class RouteAccessResponseSubscriber

class RouteAccessResponseSubscriber implements EventSubscriberInterface {
    
    /**
     * Bubbles the route's access result' cacheability metadata.
     *
     * @param \Symfony\Component\HttpKernel\Event\ResponseEvent $event
     *   The event to process.
     */
    public function onRespond(ResponseEvent $event) {
        if (!$event->isMainRequest()) {
            return;
        }
        $response = $event->getResponse();
        if (!$response instanceof CacheableResponseInterface) {
            return;
        }
        $request = $event->getRequest();
        // It is possible that route access checking did not occur, for example,
        // when an exception was thrown during route matching. This could happen in
        // an implementation of \Drupal\Core\Routing\EnhancerInterface.
        // @see \Drupal\jsonapi\Revisions\ResourceVersionRouteEnhancer::enhance()
        if ($request->attributes
            ->has(AccessAwareRouterInterface::ACCESS_RESULT)) {
            $response->addCacheableDependency($request->attributes
                ->get(AccessAwareRouterInterface::ACCESS_RESULT));
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function getSubscribedEvents() : array {
        // Priority 10, so that it runs before FinishResponseSubscriber, which will
        // expose the cacheability metadata in the form of headers.
        $events[KernelEvents::RESPONSE][] = [
            'onRespond',
            10,
        ];
        return $events;
    }

}