Merge various docs into one session doc

Author: fabpot

components/http_foundation/session_php_bridge.rst

@@ -391,128 +391,10 @@ Request object.
    single: Controller; The session
    single: Session
 
-.. _session-intro:
-
 Managing the Session
 --------------------
 
-Symfony provides a session object that you can use to store information
-about the user between requests. Session is enabled by default, but will only be
-started if you read or write from it.
-
-Session storage and other configuration can be controlled under the
-:ref:`framework.session configuration <config-framework-session>` in
-``config/packages/framework.yaml``.
-
-To get the session, add an argument and type-hint it with
-:class:`Symfony\\Component\\HttpFoundation\\Session\\SessionInterface`::
-
-    use Symfony\Component\HttpFoundation\Response;
-    use Symfony\Component\HttpFoundation\Session\SessionInterface;
-    // ...
-
-    public function index(SessionInterface $session): Response
-    {
-        // stores an attribute for reuse during a later user request
-        $session->set('foo', 'bar');
-
-        // gets the attribute set by another controller in another request
-        $foobar = $session->get('foobar');
-
-        // uses a default value if the attribute doesn't exist
-        $filters = $session->get('filters', []);
-
-        // ...
-    }
-
-Stored attributes remain in the session for the remainder of that user's session.
-
-For more info, see :doc:`/session`.
-
-.. index::
-   single: Session; Flash messages
-
-.. _flash-messages:
-
-Flash Messages
-~~~~~~~~~~~~~~
-
-You can also store special messages, called "flash" messages, on the user's
-session. By design, flash messages are meant to be used exactly once: they vanish
-from the session automatically as soon as you retrieve them. This feature makes
-"flash" messages particularly great for storing user notifications.
-
-For example, imagine you're processing a :doc:`form </forms>` submission::
-
-    use Symfony\Component\HttpFoundation\Request;
-    use Symfony\Component\HttpFoundation\Response;
-    // ...
-
-    public function update(Request $request): Response
-    {
-        // ...
-
-        if ($form->isSubmitted() && $form->isValid()) {
-            // do some sort of processing
-
-            $this->addFlash(
-                'notice',
-                'Your changes were saved!'
-            );
-            // $this->addFlash() is equivalent to $request->getSession()->getFlashBag()->add()
-
-            return $this->redirectToRoute(/* ... */);
-        }
-
-        return $this->render(/* ... */);
-    }
-
-After processing the request, the controller sets a flash message in the session
-and then redirects. The message key (``notice`` in this example) can be anything:
-you'll use this key to retrieve the message.
-
-In the template of the next page (or even better, in your base layout template),
-read any flash messages from the session using the ``flashes()`` method provided
-by the :ref:`Twig global app variable <twig-app-variable>`:
-
-.. code-block:: html+twig
-
-    {# templates/base.html.twig #}
-
-    {# read and display just one flash message type #}
-    {% for message in app.flashes('notice') %}
-        <div class="flash-notice">
-            {{ message }}
-        </div>
-    {% endfor %}
-
-    {# read and display several types of flash messages #}
-    {% for label, messages in app.flashes(['success', 'warning']) %}
-        {% for message in messages %}
-            <div class="flash-{{ label }}">
-                {{ message }}
-            </div>
-        {% endfor %}
-    {% endfor %}
-
-    {# read and display all flash messages #}
-    {% for label, messages in app.flashes %}
-        {% for message in messages %}
-            <div class="flash-{{ label }}">
-                {{ message }}
-            </div>
-        {% endfor %}
-    {% endfor %}
-
-It's common to use ``notice``, ``warning`` and ``error`` as the keys of the
-different types of flash messages, but you can use any key that fits your
-needs.
-
-.. tip::
-
-    You can use the
-    :method:`Symfony\\Component\\HttpFoundation\\Session\\Flash\\FlashBagInterface::peek`
-    method instead to retrieve the message while keeping it in the bag.
+:ref:`Reading <session-intro>` for more information about using Sessions.
 
 .. index::
    single: Controller; Response object