1-33

Symfony2 – Franz Jordán 2011
$mailer = $this->get('mailer');
There are countless other services available and you are encouraged to define your own. To list
all available services, use the container:debug console command:
php app/console container:debug
For more information, see the Service Container chapter.
Managing Errors and 404 Pages
When things are not found, you should play well with the HTTP protocol and return a 404
response. To do this, you'll throw a special type of exception. If you're extending the base
controller class, do the following:
public function indexAction()
{
$product = // retrieve the object from database
if (!$product) {
throw $this->createNotFoundException('The product does not exist');
}
return $this->render(...);
}
The createNotFoundException() method creates a
special NotFoundHttpException object, which ultimately triggers a 404 HTTP response
inside Symfony.
Of course, you're free to throw any Exception class in your controller - Symfony2 will
automatically return a 500 HTTP response code.
throw new \Exception('Something went wrong!');
In every case, a styled error page is shown to the end user and a full debug error page is shown
to the developer (when viewing the page in debug mode). Both of these error pages can be
customized. For details, read the "How to customize Error Pages" cookbook recipe.
Managing the Session
Symfony2 provides a nice session object that you can use to store information about the user (be
it a real person using a browser, a bot, or a web service) between requests. By default, Symfony2
stores the attributes in a cookie by using the native PHP sessions.
Storing and retrieving information from the session can be easily achieved from any controller:
$session = $this->getRequest()->getSession();
// store an attribute for reuse during a later user request
$session->set('foo', 'bar');
// in another controller for another request
$foo = $session->get('foo');
// set the user locale
52