Redirect to page prior to login form Symfony 3.4 is resolving to liip_imagine route in a custom listener

I'm having problems getting a redirect after login to work in Symfony.

It works for some pages but for others, the last_route session variable is being set to a users profile picture that uses the liip_imagine_filter:

"last_route" => [
        "name" => "liip_imagine_filter",
        "params" => [
          "filter" => "profile_picture"
          "path" => "frederick-jacobson/5ba60fc93056b.png"
        ]
      ]

LoginFormAuthenticator:

class LoginFormAuthenticator extends AbstractFormLoginAuthenticator
{

       /*...*/

        protected function getDefaultSuccessRedirectURL()
        {
            /** @var Session $session */
            $session = $this->container->get('session');
            $priorPage = $session->get('last_route');

            return $this->router->generate($priorPage['name'], $priorPage['params']);
    //        return $this->router->generate('poll_index');
        }
}

This means that it tries to redirect to an image URL.

services.yml:

poll.last_route_event_listener:
    class: PollBundle\Services\LastRouteListener
    tags:
        - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest, priority: 30 }

LastRouteListener:

use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\HttpKernel\HttpKernel;

class LastRouteListener
{
    public function onKernelRequest(GetResponseEvent $event)
    {
        // Do not save subrequests
        if ($event->getRequestType() !== HttpKernel::MASTER_REQUEST) {
            return;
        }
        $request = $event->getRequest();
        $session = $request->getSession();
        $routeName = $request->get('_route');
        $routeParams = $request->get('_route_params');
        if ($routeName[0] == '_') {
            return;
        }
        $routeData = ['name' => $routeName, 'params' => $routeParams];
        // Do not save same matched route twice
        $thisRoute = $session->get('this_route', []);
        if ($thisRoute == $routeData) {
            return;
        }
        $session->set('last_route', $thisRoute);
        $session->set('this_route', $routeData);
    }
}

Can someone please help me work out what I'm doing wrong and/or tell me the correct way to handle redirecting to the page prior to login?

As pointed out in the comments below my question. I was using a custom listener that was picking up the liip_imagine_filter route and setting it to the last_route session variable.

I could just add a check in to the listener, like this:

if ($routeName[0] == '_' || $routeName == 'liip_imagine_filter') {
    return;
}

But a better way to handle it is to use the built in Symfony\Component\Security\Http\Util\TargetPathTrait

It is usually set automatically when a user hits a restricted page, but it can be set manually with $this->saveTargetPath($request->getSession(), $providerKey, $request->getUri());

Then you can use $targetPath to find the route to redirect to in LoginFormAuthenticator:

use Symfony\Component\Security\Http\Util\TargetPathTrait;


class LoginFormAuthenticator extends AbstractFormLoginAuthenticator
{

   /*...*/

    use TargetPathTrait;
    public function onAuthenticationSuccess(Request $request, TokenInterface $token, $providerKey)
        {
            $targetPath = $this->getTargetPath($request->getSession(), $providerKey);

            if (!$targetPath || $request->getBaseUrl() && !strpos($targetPath, $request->getBaseUrl())) {
                $targetPath = $this->container->get('router')
                    ->generate('poll_index');
            }

            return new RedirectResponse($targetPath);
        }
}