Documented how to simulate old way of saving locale

cookbook/map.rst.inc

@@ -102,6 +102,7 @@
 * :doc:`/cookbook/request/index`
 
   * :doc:`/cookbook/request/mime_type`
+  * (session) :doc:`/cookbook/session/simulate_locale_in_session`
 
 * :doc:`/cookbook/routing/index`
 
@@ -135,6 +136,7 @@
 * :doc:`/cookbook/session/index`
 
   * :doc:`/cookbook/session/proxy_examples`
+  * :doc:`/cookbook/session/simulate_locale_in_session`
 
 * **symfony1**
 

cookbook/session/index.rst

@@ -5,3 +5,4 @@ Sessions
     :maxdepth: 2
 
     proxy_examples
+    simulate_locale_in_session

cookbook/session/simulate_locale_in_session.rst

@@ -0,0 +1,90 @@
+.. index::
+    single: Sessions, saving locale
+
+Simulate old Behaviour of Saving the Locale
+===========================================
+
+Prior to Symfony 2.1, the locale was stored in a session called ``_locale``.
+Since 2.1, it is stored in the Request. You'll learn how to simulate the old
+way in this article.
+
+Creating LocaleListener
+-----------------------
+
+To simulate that the locale is stored in a session, you need to create and
+register a new listener. The listener will look like the following, assuming
+that the parameter which handels the locale value in the request is called
+``_locale``::
+
+    // src/Acme/LocaleBundle/EventListener/LocaleListener.php
+    namespace Acme\LocaleBundle\EventListener;
+
+    use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+    use Symfony\Component\HttpKernel\KernelEvents;
+    use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+    class LocaleListener implements EventSubscriberInterface
+    {
+        private $defaultLocale;
+
+        public function __construct($defaultLocale = 'en')
+        {
+            $this->defaultLocale = $defaultLocale;
+        }
+
+        public function onKernelRequest(GetResponseEvent $event)
+        {
+            $request = $event->getRequest();
+            if (!$request->hasPreviousSession()) {
+                return;
+            }
+
+            if ($locale = $request->attributes->get('_locale')) {
+                $request->getSession()->set('_locale', $locale);
+            } else {
+                $request->setLocale($request->getSession()->get('_locale', $this->defaultLocale));
+            }
+        }
+
+        public static function getSubscribedEvents()
+        {
+            return array(
+                // must be registered before the default Locale listener
+                KernelEvents::REQUEST => array(array('onKernelRequest', 17)),
+            );
+        }
+    }
+
+Then register the listener:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        services:
+            acme_locale.locale_listener:
+                class: Acme\LocaleBundle\EventListener\LocaleListener
+                arguments: ["%kernel.default_locale%"]
+                tags:
+                    - { name: kernel.event_subscriber }
+
+    .. code-block:: xml
+
+        <service id="acme_locale.locale_listener"
+            class="Acme\LocaleBundle\EventListener\LocaleListener">
+            <argument>%kernel.default_locale%</argument>
+
+            <tag name="kernel.event_subscriber" />
+        </service>
+
+    .. code-block:: php
+
+        use Symfony\Component\DependencyInjection\Definition;
+
+        $container
+            ->setDefinition('acme_locale.locale_listener', new Definition(
+                'Acme\LocaleBundle\EventListener\LocaleListener',
+                array('%kernel.default_locale%')
+            ))
+            ->addTag('kernel.event_subscriber')
+        ;