Refactor DrupalKernel to extend HttpKernel.

core/lib/Drupal/Core/DrupalKernel.php

@@ -5,15 +5,14 @@
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\RequestContext;
-use Symfony\Component\HttpKernel\HttpKernelInterface;
 use Symfony\Component\HttpKernel\HttpKernel;
 use Symfony\Component\HttpKernel\KernelEvents;
-use Symfony\Component\HttpKernel\Controller\ControllerResolver;
-use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 use Symfony\Component\EventDispatcher\Event;
+use Symfony\Component\HttpKernel\Controller\ControllerResolverInterface;
 use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
 use Symfony\Component\HttpKernel\EventListener\RouterListener;
-
+use Symfony\Component\HttpKernel\EventListener\ExceptionListener;
 use Drupal\Core\EventSubscriber\HtmlSubscriber;
 use Drupal\Core\EventSubscriber\JsonSubscriber;
 use Drupal\Core\EventSubscriber\AccessSubscriber;
@@ -31,7 +30,45 @@
 /**
  * The DrupalApp class is the core of Drupal itself.
  */
-class DrupalKernel implements HttpKernelInterface {
+class DrupalKernel extends HttpKernel {
+    protected $dispatcher;
+    protected $resolver;
+
+
+    /**
+     * Constructor
+     *
+     * @param EventDispatcherInterface    $dispatcher An EventDispatcherInterface instance
+     * @param ControllerResolverInterface $resolver   A ControllerResolverInterface instance
+     *
+     * @api
+     */
+   public function __construct(EventDispatcherInterface $dispatcher, ControllerResolverInterface $resolver) {
+      parent::__construct($dispatcher, $resolver);
+      $this->dispatcher = $dispatcher;
+      $this->resolver = $resolver;
+
+      // @todo Make this extensible rather than just hard coding some.
+      // @todo Add a subscriber to handle other things, too, like our Ajax
+      // replacement system.
+      $this->dispatcher->addSubscriber(new HtmlSubscriber());
+      $this->dispatcher->addSubscriber(new JsonSubscriber());
+      $this->dispatcher->addSubscriber(new AccessSubscriber());
+      $this->dispatcher->addSubscriber(new PathSubscriber());
+      $this->dispatcher->addSubscriber(new LegacyControllerSubscriber());
+
+      // Some other form of error occured that wasn't handled by another kernel
+      // listener.  That could mean that it's a method/mime-type/error
+      // combination that is not accounted for, or some other type of error.
+      // Either way, treat it as a server-level error and return an HTTP 500.
+      // By default, this will be an HTML-type response because that's a decent
+      // best guess if we don't know otherwise.
+      $this->dispatcher->addSubscriber(new ExceptionListener(function(Exception $e) {
+        return new Response('A fatal error occurred: ' . $e->getMessage(), 500);
+      }));
+
+
+    }
 
   /**
    *
@@ -41,32 +78,11 @@ class DrupalKernel implements HttpKernelInterface {
    *   The response object to return to the requesting user agent.
    */
   function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true) {
-    try {
-
-      $dispatcher = $this->getDispatcher();
-
+    if ($type == self::MASTER_REQUEST) {
       $matcher = $this->getMatcher($request);
-      $dispatcher->addSubscriber(new RouterListener($matcher));
-      $dispatcher->addSubscriber(new AccessSubscriber());
-      $dispatcher->addSubscriber(new PathSubscriber());
-      $dispatcher->addSubscriber(new LegacyControllerSubscriber());
-
-      $resolver = new ControllerResolver();
-
-      $kernel = new HttpKernel($dispatcher, $resolver);
-      $response = $kernel->handle($request);
+      $this->dispatcher->addSubscriber(new RouterListener($matcher));
     }
-    catch (Exception $e) {
-      // Some other form of error occured that wasn't handled by another kernel
-      // listener.  That could mean that it's a method/mime-type/error
-      // combination that is not accounted for, or some other type of error.
-      // Either way, treat it as a server-level error and return an HTTP 500.
-      // By default, this will be an HTML-type response because that's a decent
-      // best guess if we don't know otherwise.
-      $response = new Response('A fatal error occurred: ' . $e->getMessage(), 500);
-    }
-
-    return $response;
+    return parent::handle($request, $type, $catch);
   }
 
   /**
@@ -80,13 +96,7 @@ function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true) {
    * @return EventDispatcher
    */
   protected function getDispatcher() {
-    $dispatcher = new EventDispatcher();
 
-    // @todo Make this extensible rather than just hard coding some.
-    // @todo Add a subscriber to handle other things, too, like our Ajax
-    // replacement system.
-    $dispatcher->addSubscriber(new HtmlSubscriber());
-    $dispatcher->addSubscriber(new JsonSubscriber());
 
     return $dispatcher;
   }

index.php

@@ -2,6 +2,9 @@
 
 use Drupal\Core\DrupalKernel;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\HttpKernel\Controller\ControllerResolver;
+
 
 /**
  * @file
@@ -26,5 +29,9 @@
 // A request object from the HTTPFoundation to tell us about the request.
 $request = Request::createFromGlobals();
 
-$kernel = new DrupalKernel();
+
+$dispatcher = new EventDispatcher();
+$resolver = new ControllerResolver();
+
+$kernel = new DrupalKernel($dispatcher, $resolver);
 $kernel->handle($request)->send();