Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Access;
Chris@0: 
Chris@0: use Drupal\Core\Routing\Access\AccessInterface as RoutingAccessInterface;
Chris@0: use Drupal\Core\Routing\RouteMatchInterface;
Chris@0: use Symfony\Component\Routing\Route;
Chris@0: use Symfony\Component\HttpFoundation\Request;
Chris@0: 
Chris@0: /**
Chris@0:  * Allows access to routes to be controlled by a '_csrf_token' parameter.
Chris@0:  *
Chris@0:  * To use this check, add a "token" GET parameter to URLs of which the value is
Chris@0:  * a token generated by \Drupal::csrfToken()->get() using the same value as the
Chris@0:  * "_csrf_token" parameter in the route.
Chris@0:  */
Chris@0: class CsrfAccessCheck implements RoutingAccessInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The CSRF token generator.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Access\CsrfTokenGenerator
Chris@0:    */
Chris@0:   protected $csrfToken;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a CsrfAccessCheck object.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Access\CsrfTokenGenerator $csrf_token
Chris@0:    *   The CSRF token generator.
Chris@0:    */
Chris@0:   public function __construct(CsrfTokenGenerator $csrf_token) {
Chris@0:     $this->csrfToken = $csrf_token;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Checks access based on a CSRF token for the request.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\Routing\Route $route
Chris@0:    *   The route to check against.
Chris@0:    * @param \Symfony\Component\HttpFoundation\Request $request
Chris@0:    *   The request object.
Chris@0:    * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
Chris@0:    *   The route match object.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Access\AccessResultInterface
Chris@0:    *   The access result.
Chris@0:    */
Chris@0:   public function access(Route $route, Request $request, RouteMatchInterface $route_match) {
Chris@0:     $parameters = $route_match->getRawParameters();
Chris@0:     $path = ltrim($route->getPath(), '/');
Chris@0:     // Replace the path parameters with values from the parameters array.
Chris@0:     foreach ($parameters as $param => $value) {
Chris@0:       $path = str_replace("{{$param}}", $value, $path);
Chris@0:     }
Chris@0: 
Chris@0:     if ($this->csrfToken->validate($request->query->get('token', ''), $path)) {
Chris@0:       $result = AccessResult::allowed();
Chris@0:     }
Chris@0:     else {
Chris@0:       $result = AccessResult::forbidden($request->query->has('token') ? "'csrf_token' URL query argument is invalid." : "'csrf_token' URL query argument is missing.");
Chris@0:     }
Chris@0:     // Not cacheable because the CSRF token is highly dynamic.
Chris@0:     return $result->setCacheMaxAge(0);
Chris@0:   }
Chris@0: 
Chris@0: }