Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\EventSubscriber;
Chris@0: 
Chris@0: use Drupal\Core\Routing\RouteBuildEvent;
Chris@0: use Drupal\Core\Routing\RouteSubscriberBase;
Chris@0: use Symfony\Cmf\Component\Routing\RouteObjectInterface;
Chris@0: use Symfony\Component\Routing\RouteCollection;
Chris@0: 
Chris@0: /**
Chris@0:  * Provides a route subscriber which checks for invalid pattern variables.
Chris@0:  */
Chris@0: class SpecialAttributesRouteSubscriber extends RouteSubscriberBase {
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   protected function alterRoutes(RouteCollection $collection) {
Chris@0:     $special_variables = [
Chris@0:       'system_path',
Chris@0:       '_legacy',
Chris@0:       '_raw_variables',
Chris@0:       RouteObjectInterface::ROUTE_OBJECT,
Chris@0:       RouteObjectInterface::ROUTE_NAME,
Chris@0:       '_content',
Chris@0:       '_controller',
Chris@0:       '_form',
Chris@0:     ];
Chris@0:     foreach ($collection->all() as $name => $route) {
Chris@0:       if ($not_allowed_variables = array_intersect($route->compile()->getVariables(), $special_variables)) {
Chris@0:         $reserved = implode(', ', $not_allowed_variables);
Chris@0:         trigger_error(sprintf('Route %s uses reserved variable names: %s', $name, $reserved), E_USER_WARNING);
Chris@0:       }
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Delegates the route altering to self::alterRoutes().
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Routing\RouteBuildEvent $event
Chris@0:    *   The route build event.
Chris@0:    */
Chris@0:   public function onAlterRoutes(RouteBuildEvent $event) {
Chris@0:     $collection = $event->getRouteCollection();
Chris@0:     $this->alterRoutes($collection);
Chris@0:   }
Chris@0: 
Chris@0: }