Issue #2026431 by YesCT, dawehner, Crell: Make ContentNegotiation a 'internal' service, used only by the router, so that core or contrib can implement real negotiation.

core/core.services.yml

@@ -429,27 +429,21 @@ services:
     tags:
       - { name: route_enhancer, priority: 1000 }
     arguments: ['@authentication']
-  route_enhancer.content_controller:
-    class: Drupal\Core\Routing\Enhancer\ContentControllerEnhancer
-    arguments: ['@content_negotiation']
-    tags:
-      - { name: route_enhancer, priority: 30 }
-  route_enhancer.ajax:
-    class: Drupal\Core\Routing\Enhancer\AjaxEnhancer
-    arguments: ['@content_negotiation']
-    tags:
-      - { name: route_enhancer, priority: 15 }
-      - { name: legacy_route_enhancer, priority: 15 }
   route_enhancer.entity:
     class: Drupal\Core\Entity\Enhancer\EntityRouteEnhancer
     arguments: ['@controller_resolver', '@entity.manager', '@form_builder']
     tags:
       - { name: route_enhancer, priority: 20 }
-  route_enhancer.form:
-    class: Drupal\Core\Routing\Enhancer\FormEnhancer
+  route_content_controller_subscriber:
+    class: Drupal\Core\EventSubscriber\ContentControllerSubscriber
+    arguments: ['@content_negotiation']
+    tags:
+      - { name: event_subscriber }
+  route_content_form_controller_subscriber:
+    class: Drupal\Core\EventSubscriber\ContentFormControllerSubscriber
     arguments: ['@service_container', '@controller_resolver', '@form_builder']
     tags:
-      - { name: route_enhancer, priority: 10 }
+      - { name: event_subscriber }
   route_special_attributes_subscriber:
     class: Drupal\Core\EventSubscriber\SpecialAttributesRouteSubscriber
     tags:

core/lib/Drupal/Core/EventSubscriber/ContentControllerSubscriber.php

@@ -0,0 +1,93 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\EventSubscriber\ContentControllerSubscriber.
+ */
+
+namespace Drupal\Core\EventSubscriber;
+
+use Drupal\Core\ContentNegotiation;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+
+/**
+ * Defines a subscriber for setting the format of the request.
+ */
+class ContentControllerSubscriber implements EventSubscriberInterface {
+
+  /**
+   * Content negotiation library.
+   *
+   * @var \Drupal\Core\ContentNegotiation
+   */
+  protected $negotiation;
+
+  /**
+   * Constructs a new ContentControllerSubscriber object.
+   *
+   * @param \Drupal\Core\ContentNegotiation $negotiation
+   *   The Content Negotiation service.
+   */
+  public function __construct(ContentNegotiation $negotiation) {
+    $this->negotiation = $negotiation;
+  }
+
+  /**
+   * Associative array of supported mime types and their appropriate controller.
+   *
+   * @var array
+   */
+  protected $types = array(
+    'drupal_dialog' => 'controller.dialog:dialog',
+    'drupal_modal' => 'controller.dialog:modal',
+    'html' => 'controller.page:content',
+    'drupal_ajax' => 'controller.ajax:content',
+  );
+
+  /**
+   * Sets the derived request format on the request.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
+   *   The event to process.
+   */
+  public function onRequestDeriveFormat(GetResponseEvent $event) {
+    $request = $event->getRequest();
+
+    if (!$request->attributes->get('_format')) {
+      $request->setRequestFormat($this->negotiation->getContentType($request));
+    }
+  }
+
+  /**
+   * Sets the _controller on a request based on the request format.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
+   *   The event to process.
+   */
+  public function onRequestDeriveContentWrapper(GetResponseEvent $event) {
+    $request = $event->getRequest();
+
+    $controller = $request->attributes->get('_controller');
+    if (empty($controller) && ($type = $request->getRequestFormat())) {
+      if (isset($this->types[$type])) {
+        $request->attributes->set('_controller', $this->types[$type]);
+      }
+    }
+  }
+
+  /**
+   * Registers the methods in this class that should be listeners.
+   *
+   * @return array
+   *   An array of event listener definitions.
+   */
+  static function getSubscribedEvents() {
+    $events[KernelEvents::REQUEST][] = array('onRequestDeriveFormat', 31);
+    $events[KernelEvents::REQUEST][] = array('onRequestDeriveContentWrapper', 30);
+
+    return $events;
+  }
+
+}

core/lib/Drupal/Core/EventSubscriber/ContentFormControllerSubscriber.php

@@ -2,22 +2,23 @@
 
 /**
  * @file
- * Contains \Drupal\Core\Routing\Enhancer\FormEnhancer.
+ * Definition of Drupal\Core\EventSubscriber\ContentFormControllerSubscriber.
  */
 
-namespace Drupal\Core\Routing\Enhancer;
+namespace Drupal\Core\EventSubscriber;
 
 use Drupal\Core\Controller\HtmlFormController;
 use Drupal\Core\Controller\ControllerResolverInterface;
 use Drupal\Core\Form\FormBuilderInterface;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface;
 
 /**
- * Enhances a form route with the appropriate controller.
+ * Subscriber for setting wrapping form logic.
  */
-class FormEnhancer implements RouteEnhancerInterface {
+class ContentFormControllerSubscriber implements EventSubscriberInterface {
 
   /**
    * The service container.
@@ -41,7 +42,7 @@ class FormEnhancer implements RouteEnhancerInterface {
   protected $formBuilder;
 
   /**
-   * Constructs a new \Drupal\Core\Routing\Enhancer\FormEnhancer object.
+   * Constructs a new ContentFormControllerSubscriber object.
    *
    * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
    *   The service container.
@@ -57,14 +58,29 @@ class FormEnhancer implements RouteEnhancerInterface {
   }
 
   /**
-   * {@inheritdoc}
+   * Sets the _controllere on a request based on the request format.
+   *
+   * @param \Symfony\Component\HttpKernel\Event\GetResponseEvent $event
+   *   The event to process.
    */
-  public function enhance(array $defaults, Request $request) {
-    if (!empty($defaults['_form'])) {
-      $wrapper = new HtmlFormController($this->resolver, $this->container, $defaults['_form'], $this->formBuilder);
-      $defaults['_content'] = array($wrapper, 'getContentResult');
+  public function onRequestDeriveFormWrapper(GetResponseEvent $event) {
+    $request = $event->getRequest();
+
+    if ($form = $request->attributes->get('_form')) {
+      $wrapper = new HtmlFormController($this->resolver, $this->container, $form, $this->formBuilder);
+      $request->attributes->set('_content', array($wrapper, 'getContentResult'));
     }
-    return $defaults;
   }
 
+  /**
+   * Registers the methods in this class that should be listeners.
+   *
+   * @return array
+   *   An array of event listener definitions.
+   */
+  static function getSubscribedEvents() {
+    $events[KernelEvents::REQUEST][] = array('onRequestDeriveFormWrapper', 29);
+
+    return $events;
+  }
 }

core/lib/Drupal/Core/Routing/Enhancer/ContentControllerEnhancer.php

@@ -1,61 +0,0 @@
-<?php
-
-/**
- * @file
- * Contains \Drupal\Core\Routing\Enhancer\ContentControllerEnhancer.
- */
-
-namespace Drupal\Core\Routing\Enhancer;
-
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Cmf\Component\Routing\Enhancer\RouteEnhancerInterface;
-use Drupal\Core\ContentNegotiation;
-
-/**
- * Enhances a route to select a controller based on the mime type of the request.
- */
-class ContentControllerEnhancer implements RouteEnhancerInterface {
-
-  /**
-   * Content negotiation library.
-   *
-   * @var \Drupal\Core\ContentNegotiation
-   */
-  protected $negotiation;
-
-  /**
-   * Associative array of supported mime types and their appropriate controller.
-   *
-   * @var array
-   */
-  protected $types = array(
-    'drupal_dialog' => 'controller.dialog:dialog',
-    'drupal_modal' => 'controller.dialog:modal',
-    'html' => 'controller.page:content',
-    'drupal_ajax' => 'controller.ajax:content',
-  );
-
-  /**
-   * Constructs a new ContentControllerEnhancer object.
-   *
-   * @param \Drupal\Core\ContentNegotiation $negotiation
-   *   The Content Negotiation service.
-   */
-  public function __construct(ContentNegotiation $negotiation) {
-    $this->negotiation = $negotiation;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function enhance(array $defaults, Request $request) {
-    // If no controller is set and either _content is set or the request is
-    // for a dialog or modal, then enhance.
-    if (empty($defaults['_controller']) && ($type = $this->negotiation->getContentType($request))) {
-      if (isset($this->types[$type])) {
-        $defaults['_controller'] = $this->types[$type];
-      }
-    }
-    return $defaults;
-  }
-}

core/modules/system/system.routing.yml

@@ -1,7 +1,7 @@
 system.ajax:
   path: '/system/ajax'
   defaults:
-    _controller: '\Drupal\system\Controller\FormAjaxController::content'
+    _content: '\Drupal\system\Controller\FormAjaxController::content'
   options:
     _theme: ajax_base_page
   requirements: