How to define Controllers as Services

In the book, you’ve learned how easily a controller can be used when it extends the base Symfony\Bundle\FrameworkBundle\Controller\Controller class. While this works fine, controllers can also be specified as services.

To refer to a controller that’s defined as a service, use the single colon (:) notation. For example, suppose we’ve defined a service called my_controller and we want to forward to a method called indexAction() inside the service:

$this->forward('my_controller:indexAction', array('foo' => $bar));

You need to use the same notation when defining the route _controller value:

my_controller:
    pattern:   /
    defaults:  { _controller: my_controller:indexAction }

To use a controller in this way, it must be defined in the service container configuration. For more information, see the Service Container chapter.

When using a controller defined as a service, it will most likely not extend the base Controller class. Instead of relying on its shortcut methods, you’ll interact directly with the services that you need. Fortunately, this is usually pretty easy and the base Controller class itself is a great source on how to perform many common tasks.

Note

Specifying a controller as a service takes a little bit more work. The primary advantage is that the entire controller or any services passed to the controller can be modified via the service container configuration. This is especially useful when developing an open-source bundle or any bundle that will be used in many different projects. So, even if you don’t specify your controllers as services, you’ll likely see this done in some open-source Symfony2 bundles.