Symfony2 Event Listener that allows you to set Response parameters and still use the @template annotation from the SensioFrameworkExtraBundle

ExampleController.php

<?php

namespace Example\AppBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller,
    Symfony\Component\HttpFoundation\Request,
    Sensio\Bundle\FrameworkExtraBundle\Configuration\Template;

class ExampleController extends Controller
{
    /**
     * @Template
     */
    public function indexAction(Request $request)
    {
        return array(
             'statusCode' => '... some status code ...',
             'lastModified' => '... some date ...',
        );
    }
}

ResponseListener.php

<?php

namespace Example\AppBundle\EventListener;

use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;

class ResponseListener
{
    /**
     * @var array
     */
    protected $_responseParameters = array(
        'last_modified' => 'setLastModified',
        'status_code'   => 'setStatusCode',
    );

    /**
     * @param GetResponseForControllerResultEvent $event A GetResponseForControllerResultEvent instance
     */
    public function onKernelView(GetResponseForControllerResultEvent $event)
    {
        $request    = $event->getRequest();
        $parameters = $event->getControllerResult();

        if (!empty($parameters)) {
            $response = array();
            foreach ($parameters as $parameter => $value) {
                if (isset($this->_responseParameters[$parameter])) {
                    $response[$parameter] = $value;
                }
            }

            if (!empty($response)) {
                $request->attributes->set('_response', $response);
            }
        }
    }

    /**
     * @param GetResponseForControllerResultEvent $event A GetResponseForControllerResultEvent instance
     */
    public function onKernelResponse(FilterResponseEvent $event)
    {
        $request    = $event->getRequest();
        $parameters = $request->attributes->get('_response');

        if (!empty($parameters)) {
            $response = $event->getResponse();
            foreach ($parameters as $parameter => $value) {
                $method = $this->_responseParameters[$parameter];
                $response->{$method}($value);
            }
        }
    }
}