Merge branch '3.4' into 4.0

* 3.4:
  Remove some unneeded changes
  Don't use env vars in all config examples
  add more trailing comma on last array element #9493
  add trailing comma on last array element #9493
  codestyle
  add documentation for external parameters and pdo host parameter

Author: javiereguiluz

doctrine/pdo_session_storage.rst

@@ -23,7 +23,7 @@ To use it, first register a new handler service:
 
             Symfony\Component\HttpFoundation\Session\Storage\Handler\PdoSessionHandler:
                 arguments:
-                    - 'mysql:dbname=mydatabase'
+                    - 'mysql:dbname=mydatabase, host=myhost'
                     - { db_username: myuser, db_password: mypassword }
 
                     # If you're using Doctrine & want to re-use that connection, then:
@@ -43,7 +43,7 @@ To use it, first register a new handler service:
 
             <services>
                 <service id="Symfony\Component\HttpFoundation\Session\Storage\Handler\PdoSessionHandler" public="false">
-                    <argument>mysql:dbname=mydatabase</argument>
+                    <argument>mysql:dbname=mydatabase, host=myhost</argument>
                     <argument type="collection">
                         <argument key="db_username">myuser</argument>
                         <argument key="db_password">mypassword</argument>
@@ -59,11 +59,17 @@ To use it, first register a new handler service:
 
         $storageDefinition = $container->autowire(PdoSessionHandler::class)
             ->setArguments(array(
-                'mysql:dbname=mydatabase',
-                array('db_username' => 'myuser', 'db_password' => 'mypassword')
+                'mysql:dbname=mydatabase, host=myhost',
+                array('db_username' => 'myuser', 'db_password' => 'mypassword'),
             ))
         ;
 
+.. tip::
+
+    Configure the database credentials as
+    :doc:`parameters defined with environment variables </configuration/external_parameters>`
+    to make your application more secure.
+
 Next, tell Symfony to use your service as the session handler:
 
 .. configuration-block::
@@ -115,8 +121,8 @@ a second array argument to ``PdoSessionHandler``:
 
             Symfony\Component\HttpFoundation\Session\Storage\Handler\PdoSessionHandler:
                 arguments:
-                    - 'mysql:dbname=mydatabase'
-                    - { db_table: sessions, db_username: myuser, db_password: mypassword }
+                    - 'mysql:dbname=mydatabase, host=myhost'
+                    - { db_table: 'sessions', db_username: 'myuser', db_password: 'mypassword' }
 
     .. code-block:: xml
 
@@ -129,7 +135,7 @@ a second array argument to ``PdoSessionHandler``:
 
             <services>
                 <service id="Symfony\Component\HttpFoundation\Session\Storage\Handler\PdoSessionHandler" public="false">
-                    <argument>mysql:dbname=mydatabase</argument>
+                    <argument>mysql:dbname=mydatabase, host=myhost</argument>
                     <argument type="collection">
                         <argument key="db_table">sessions</argument>
                         <argument key="db_username">myuser</argument>
@@ -148,7 +154,7 @@ a second array argument to ``PdoSessionHandler``:
 
         $container->autowire(PdoSessionHandler::class)
             ->setArguments(array(
-                'mysql:dbname=mydatabase',
+                'mysql:dbname=mydatabase, host=myhost',
                 array('db_table' => 'sessions', 'db_username' => 'myuser', 'db_password' => 'mypassword')
             ))
         ;