Added the json() shortcut to the controller chapter

book/controller.rst

@@ -762,9 +762,15 @@ headers and content that's sent back to the client::
     // create a simple Response with a 200 status code (the default)
     $response = new Response('Hello '.$name, Response::HTTP_OK);
 
-    // create a JSON-response with a 200 status code
-    $response = new Response(json_encode(array('name' => $name)));
-    $response->headers->set('Content-Type', 'application/json');
+    // create a CSS-response with a 200 status code
+    $response = new Response('<style> ... </style>');
+    $response->headers->set('Content-Type', 'text/css');
+
+.. seealso::
+
+    Now that you know the basics you can continue your research on Symfony
+    ``Request`` and ``Response`` object in the
+    :ref:`HttpFoundation component documentation <component-http-foundation-request>`.
 
 There are also special classes to make certain kinds of responses easier:
 
@@ -778,11 +784,25 @@ There are also special classes to make certain kinds of responses easier:
   :class:`Symfony\\Component\\HttpFoundation\\StreamedResponse`.
   See :ref:`streaming-response`.
 
-.. seealso::
+JSON helper
+~~~~~~~~~~~
 
-    Now that you know the basics you can continue your research on Symfony
-    ``Request`` and ``Response`` object in the
-    :ref:`HttpFoundation component documentation <component-http-foundation-request>`.
+Returning JSON contents is increasingly popular for API-based applications. For
+that reason, the base controller class defines a ``json()`` method which creates
+a ``JsonResponse()`` and encodes the given contents automatically::
+
+    // ...
+    public function indexAction()
+    {
+        // returns '{"username":"jane.doe"}' and sets the proper Content-Type header
+        $data = array('username' => 'jane.doe');
+        return $this->json($data);
+    }
+
+The only required argument is the data to be sent, but ``json()`` defines three
+more optional arguments::
+
+    $this->json($data, $status = 200, $headers = array(), $context = array());
 
 Creating Static Pages
 ---------------------