diff --git a/src/CodeExplorerBundle/EventListener/ControllerListener.php b/src/CodeExplorerBundle/EventListener/ControllerListener.php
index ec66b8b68..978aab8e5 100644
--- a/src/CodeExplorerBundle/EventListener/ControllerListener.php
+++ b/src/CodeExplorerBundle/EventListener/ControllerListener.php
@@ -12,22 +12,18 @@
 namespace CodeExplorerBundle\EventListener;
 
 use CodeExplorerBundle\Twig\SourceCodeExtension;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\HttpKernel\Event\FilterControllerEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
 
 /**
  * Defines the method that 'listens' to the 'kernel.controller' event, which is
  * triggered whenever a controller is executed in the application.
  *
- * See https://symfony.com/doc/current/book/internals.html#kernel-controller-event
- *
- * Tip: listeners are common in Symfony applications, but this particular listener
- * is too advanced and too specific for the demo application needs. For more common
- * examples see https://symfony.com/doc/current/cookbook/service_container/event_listener.html
- *
  * @author Ryan Weaver <weaverryan@gmail.com>
  * @author Javier Eguiluz <javier.eguiluz@gmail.com>
  */
-class ControllerListener
+class ControllerListener implements EventSubscriberInterface
 {
     private $twigExtension;
 
@@ -45,4 +41,14 @@ public function registerCurrentController(FilterControllerEvent $event)
             $this->twigExtension->setController($event->getController());
         }
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public static function getSubscribedEvents()
+    {
+        return [
+            KernelEvents::CONTROLLER => 'registerCurrentController',
+        ];
+    }
 }
diff --git a/src/CodeExplorerBundle/Resources/config/services.yml b/src/CodeExplorerBundle/Resources/config/services.yml
index aa34cc2fa..59c7563d5 100644
--- a/src/CodeExplorerBundle/Resources/config/services.yml
+++ b/src/CodeExplorerBundle/Resources/config/services.yml
@@ -1,12 +1,6 @@
 services:
-    code_explorer.twig.source_code_extension:
-        public:    false
-        class:     CodeExplorerBundle\Twig\SourceCodeExtension
-        tags:
-            - { name: twig.extension }
+    _defaults: { public: false, autoconfigure: true }
 
-    code_explorer.controller_listener:
-        class:     CodeExplorerBundle\EventListener\ControllerListener
-        arguments: ['@code_explorer.twig.source_code_extension']
-        tags:
-            - { name: kernel.event_listener, event: kernel.controller, method: registerCurrentController }
+    CodeExplorerBundle\Twig\SourceCodeExtension: ~
+
+    CodeExplorerBundle\EventListener\ControllerListener: ['@CodeExplorerBundle\Twig\SourceCodeExtension']