[HttpFoundation] Allow to configure session handlers with DSN

Author: javiereguiluz

reference/configuration/framework.rst

@@ -1243,6 +1243,58 @@ the native PHP session mechanism. Set it to ``'session.handler.native_file'`` to
 let Symfony manage the sessions itself using files to store the session
 metadata.
 
+You can also configure the session handler with a DSN. For example:
+
+.. configuration-block::
+
+    .. code-block:: yaml
+
+        # config/packages/framework.yaml
+        framework:
+            session:
+                # ...
+                handler_id: 'redis://localhost'
+                handler_id: '%env(REDIS_URL)%'
+                handler_id: '%env(DATABASE_URL)%'
+                handler_id: 'file://%kernel.project_dir%/var/sessions'
+
+    .. code-block:: xml
+
+        <!-- config/packages/framework.xml -->
+        <?xml version="1.0" encoding="UTF-8" ?>
+        <container xmlns="http://symfony.com/schema/dic/services"
+            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+            xmlns:framework="http://symfony.com/schema/dic/symfony"
+            xsi:schemaLocation="http://symfony.com/schema/dic/services
+                https://symfony.com/schema/dic/services/services-1.0.xsd
+                http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
+
+            <framework:config>
+                <framework:session enabled="true"
+                                   handler-id="redis://localhost"
+                                   handler-id="%env(REDIS_URL)%"
+                                   handler-id="%env(DATABASE_URL)%"
+                                   handler-id="file://%kernel.project_dir%/var/sessions"/>
+            </framework:config>
+        </container>
+
+    .. code-block:: php
+
+        // config/packages/framework.php
+        $container->loadFromExtension('framework', [
+            'session' => [
+                // ...
+                'handler_id' => 'redis://localhost',
+                'handler_id' => '%env(REDIS_URL)%',
+                'handler_id' => '%env(DATABASE_URL)%',
+                'handler_id' => 'file://%kernel.project_dir%/var/sessions',
+            ],
+        ]);
+
+.. versionadded:: 4.4
+
+    The option to configure the session handler with a DSN was introduced in Symfony 4.4.
+
 If you prefer to make Symfony store sessions in a database read
 :doc:`/doctrine/pdo_session_storage`.
 

session.rst

@@ -21,7 +21,7 @@ sessions, check their default configuration:
                 # enables the support of sessions in the app
                 enabled: true
                 # ID of the service used for session storage.
-                # NULL =  means that PHP's default session mechanism is used
+                # NULL means that Symfony uses PHP's default session mechanism
                 handler_id: null
                 # improves the security of the cookies used for sessions
                 cookie_secure: 'auto'
@@ -42,7 +42,7 @@ sessions, check their default configuration:
                 <!--
                     enabled: enables the support of sessions in the app
                     handler-id: ID of the service used for session storage
-                                NULL means that PHP's default session mechanism is used
+                                NULL means that Symfony uses PHP's default session mechanism
                     cookie-secure and cookie-samesite: improves the security of the cookies used for sessions
                 -->
                 <framework:session enabled="true"
@@ -60,7 +60,7 @@ sessions, check their default configuration:
                 // enables the support of sessions in the app
                 'enabled' => true,
                 // ID of the service used for session storage
-                // NULL means that PHP's default session mechanism is used
+                // NULL means that Symfony uses PHP's default session mechanism
                 'handler_id' => null,
                 // improves the security of the cookies used for sessions
                 'cookie_secure' => 'auto',