Functionality to override symfony 403 Error Access denied. Sets flash message and redirect (back to previous page, or homepage)

accessDeniedListener.php

<?php

namespace Atd\UserBundle\Listener;

use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent,
    Symfony\Component\Security\Core\Exception\AccessDeniedException,
    Symfony\Component\HttpFoundation\Request,
    Symfony\Component\HttpFoundation\RedirectResponse,
    Symfony\Component\HttpFoundation\Session\Session,
    Symfony\Component\Routing\Router;

class AccessDeniedListener
{
    protected $_session;
    protected $_router;
    protected $_request;

    public function __construct(Session $session, Router $router, Request $request)
    {
        $this->_session = $session;
        $this->_router = $router;
        $this->_request = $request;
    }

    public function onAccessDeniedException(GetResponseForExceptionEvent $event)
    {
        if ($event->getException()->getMessage() == 'Access Denied')
        {
            $this->_session->setFlash('error', 'Access Denied. You do not have permission to access this page.');
    
            if ($this->_request->headers->get('referer'))
            {
                    $route = $this->_request->headers->get('referer');
            } else {
                    $route = $this->_router->generate('_home');
            }
    
            $event->setResponse(new RedirectResponse($route));
        }
    }
}