<?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\HttpCache\HttpCache;
use Symfony\Component\HttpKernel\HttpCache\SurrogateInterface;
use Symfony\Component\HttpKernel\KernelEvents;
/**
* SurrogateListener adds a Surrogate-Control HTTP header when the Response needs to be parsed for Surrogates.
*
* @author Fabien Potencier <fabien@symfony.com>
*
* @final
*/
class SurrogateListener implements EventSubscriberInterface
{
private $surrogate;
public function __construct(SurrogateInterface $surrogate = null)
{
$this->surrogate = $surrogate;
}
/**
* Filters the Response.
*/
public function onKernelResponse(ResponseEvent $event)
{
if (!$event->isMasterRequest()) {
return;
}
$kernel = $event->getKernel();
$surrogate = $this->surrogate;
if ($kernel instanceof HttpCache) {
$surrogate = $kernel->getSurrogate();
if (null !== $this->surrogate && $this->surrogate->getName() !== $surrogate->getName()) {
$surrogate = $this->surrogate;
}
}
if (null === $surrogate) {
return;
}
$surrogate->addSurrogateControl($event->getResponse());
}
public static function getSubscribedEvents(): array
{
return [
KernelEvents::RESPONSE => 'onKernelResponse',
];
}
}