Controllers play a major role in web applications by being at the forefront of any application output. They are the endpoints, the code that executes behind each URL. In a more technical manner, we can say the controller is any callable (a function, method on an object, or a closure) that takes the HTTP request and returns an HTTP response. The response is not bound to a single format like HTML, it can be anything from XML, JSON, CSV, image, redirect, error, and so on.
Let's take a look at the previously created (partial) src/AppBundle/Controller/CustomerController.php file, more precisely its newAction method:
/**
* Creates a new Customer entity.
*
* @Route("/new", name="customer_new")
* @Method({"GET", "POST"})
*/
public function newAction(Request $request)
{
//...
return $this->render('customer/new.html.twig', array(
'customer' => $customer,
'form' => $form->createView(),
));
}If we ignore the actual data retrieval part (//…), there are three important...