<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <[email protected]>
*
* 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 Psr\Container\ContainerInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpFoundation\Session\Session;
use Symfony\Component\HttpFoundation\Session\SessionInterface;
use Symfony\Component\HttpKernel\Event\FinishRequestEvent;
use Symfony\Component\HttpKernel\Event\RequestEvent;
use Symfony\Component\HttpKernel\Event\ResponseEvent;
use Symfony\Component\HttpKernel\Exception\UnexpectedSessionUsageException;
use Symfony\Component\HttpKernel\KernelEvents;
/**
* Sets the session onto the request on the "kernel.request" event and saves
* it on the "kernel.response" event.
*
* In addition, if the session has been started it overrides the Cache-Control
* header in such a way that all caching is disabled in that case.
* If you have a scenario where caching responses with session information in
* them makes sense, you can disable this behaviour by setting the header
* AbstractSessionListener::NO_AUTO_CACHE_CONTROL_HEADER on the response.
*
* @author Johannes M. Schmitt <[email protected]>
* @author Tobias Schultze <http://tobion.de>
*
* @internal
*/
abstract class AbstractSessionListener implements EventSubscriberInterface
{
public const NO_AUTO_CACHE_CONTROL_HEADER = 'Symfony-Session-NoAutoCacheControl';
protected $container;
private $sessionUsageStack = [];
private $debug;
public function __construct(ContainerInterface $container = null, bool $debug = false)
{
$this->container = $container;
$this->debug = $debug;
}
public function onKernelRequest(RequestEvent $event)
{
if (!$event->isMasterRequest()) {
return;
}
$request = $event->getRequest();
if (!$request->hasSession()) {
$sess = null;
$request->setSessionFactory(function () use (&$sess) { return $sess ?? $sess = $this->getSession(); });
}
$session = $this->container && $this->container->has('initialized_session') ? $this->container->get('initialized_session') : null;
$this->sessionUsageStack[] = $session instanceof Session ? $session->getUsageIndex() : 0;
}
public function onKernelResponse(ResponseEvent $event)
{
if (!$event->isMasterRequest()) {
return;
}
$response = $event->getResponse();
$autoCacheControl = !$response->headers->has(self::NO_AUTO_CACHE_CONTROL_HEADER);
// Always remove the internal header if present
$response->headers->remove(self::NO_AUTO_CACHE_CONTROL_HEADER);
if (!$session = $this->container && $this->container->has('initialized_session') ? $this->container->get('initialized_session') : $event->getRequest()->getSession()) {
return;
}
if ($session->isStarted()) {
/*
* Saves the session, in case it is still open, before sending the response/headers.
*
* This ensures several things in case the developer did not save the session explicitly:
*
* * If a session save handler without locking is used, it ensures the data is available
* on the next request, e.g. after a redirect. PHPs auto-save at script end via
* session_register_shutdown is executed after fastcgi_finish_request. So in this case
* the data could be missing the next request because it might not be saved the moment
* the new request is processed.
* * A locking save handler (e.g. the native 'files') circumvents concurrency problems like
* the one above. But by saving the session before long-running things in the terminate event,
* we ensure the session is not blocked longer than needed.
* * When regenerating the session ID no locking is involved in PHPs session design. See
* https://bugs.php.net/61470 for a discussion. So in this case, the session must
* be saved anyway before sending the headers with the new session ID. Otherwise session
* data could get lost again for concurrent requests with the new ID. One result could be
* that you get logged out after just logging in.
*
* This listener should be executed as one of the last listeners, so that previous listeners
* can still operate on the open session. This prevents the overhead of restarting it.
* Listeners after closing the session can still work with the session as usual because
* Symfonys session implementation starts the session on demand. So writing to it after
* it is saved will just restart it.
*/
$session->save();
}
if ($session instanceof Session ? $session->getUsageIndex() === end($this->sessionUsageStack) : !$session->isStarted()) {
return;
}
if ($autoCacheControl) {
$response
->setExpires(new \DateTime())
->setPrivate()
->setMaxAge(0)
->headers->addCacheControlDirective('must-revalidate');
}
if (!$event->getRequest()->attributes->get('_stateless', false)) {
return;
}
if ($this->debug) {
throw new UnexpectedSessionUsageException('Session was used while the request was declared stateless.');
}
if ($this->container->has('logger')) {
$this->container->get('logger')->warning('Session was used while the request was declared stateless.');
}
}
public function onFinishRequest(FinishRequestEvent $event)
{
if ($event->isMasterRequest()) {
array_pop($this->sessionUsageStack);
}
}
public function onSessionUsage(): void
{
if (!$this->debug) {
return;
}
if ($this->container && $this->container->has('session_collector')) {
$this->container->get('session_collector')();
}
if (!$requestStack = $this->container && $this->container->has('request_stack') ? $this->container->get('request_stack') : null) {
return;
}
$stateless = false;
$clonedRequestStack = clone $requestStack;
while (null !== ($request = $clonedRequestStack->pop()) && !$stateless) {
$stateless = $request->attributes->get('_stateless');
}
if (!$stateless) {
return;
}
if (!$session = $this->container && $this->container->has('initialized_session') ? $this->container->get('initialized_session') : $requestStack->getCurrentRequest()->getSession()) {
return;
}
if ($session->isStarted()) {
$session->save();
}
throw new UnexpectedSessionUsageException('Session was used while the request was declared stateless.');
}
public static function getSubscribedEvents(): array
{
return [
KernelEvents::REQUEST => ['onKernelRequest', 128],
// low priority to come after regular response listeners, but higher than StreamedResponseListener
KernelEvents::RESPONSE => ['onKernelResponse', -1000],
KernelEvents::FINISH_REQUEST => ['onFinishRequest'],
];
}
/**
* Gets the session object.
*
* @return SessionInterface|null A SessionInterface instance or null if no session is available
*/
abstract protected function getSession();
}