<?php/* * This file is part of the Symfony package. * * (c) Fabien Potencier <fabien@symfony.com> * * For the full copyright and license information, please view the LICENSE * file that was distributed with this source code. */namespace Symfony\Component\HttpKernel\EventListener;use Symfony\Component\EventDispatcher\EventSubscriberInterface;use Symfony\Component\HttpKernel\Event\ResponseEvent;use Symfony\Component\HttpKernel\KernelEvents;/** * Ensures that the application is not indexed by search engines. * * @author Gary PEGEOT <garypegeot@gmail.com> */class DisallowRobotsIndexingListener implements EventSubscriberInterface{ private const HEADER_NAME = 'X-Robots-Tag'; public function onResponse(ResponseEvent $event): void { if (!$event->getResponse()->headers->has(static::HEADER_NAME)) { $event->getResponse()->headers->set(static::HEADER_NAME, 'noindex'); } } /** * {@inheritdoc} */ public static function getSubscribedEvents() { return [ KernelEvents::RESPONSE => ['onResponse', -255], ]; }}