Trying to swap a controller using an event listener with Symfony2

Question

I've been reading through the internals chapter in the Symfony2 docs and it says if I add a listener to the kernel.controller event I can swap the controller that gets run, I've got something that works a bit like this:

public function onKernelController(FilterControllerEvent $event)    
{
    $controller = $event->getController();

    $replacementControllerName = .... //Some logic to work out the name of the new controller
    $replacementController = ?? //Not sure what goes here

    $event->setController($replacementController);
}

The bit I'm unsure if is once I've worked out the name of the replacement controller, how do I get an instance of it that I can pass to setController?

Answer 1

You can set your controller to any callable, which means something like

• A static method array('class', 'method')
• An instance method array($instance, 'method')
• An anonymous function function() { ... }
• A regular global function 'function';
• An instance of a class implementing the __invoke() method new MyClassImplementingInvoke()
• The special syntax 'class::method' which forces the ControllerResolver to create a new instance of class (calling the constructor without any argument) and returning a callable array($instanceOfClass, 'method')

EDIT:

I looked up the wrong ControllerResolver. When running Symfony in a standard setup it'll use the Symfony\Bundle\FrameworkBundle\Controller\ControllerResolver (and not the Symfony\Component\HttpKernel\Controller\ControllerResolver). So the controller name will be handled a little bit different to what I wrote above.

The following example sums up all the possible options you have when setting your controller.

public function onKernelController(FilterControllerEvent $event)    
{
    $controller = $event->getController();
    // call method in Controller class in YourBundle
    $replacementController = 'YourBundle:Controller:method';
    // call method in service (which is a service registered in the DIC)
    $replacementController = 'service:method';
    // call method on an instance of Class (created by calling the constructor without any argument)
    $replacementController = 'Class::method';
    // call method on Class statically (static method)
    $replacementController = array('Class', 'method');
    // call method on $controller
    $controller            = new YourController(1, 2, 3);
    $replacementController = array($controller, 'method');
    // call __invoke on $controller
    $replacementController = new YourController(1, 2, 3);
    $event->setController($replacementController);
}