Symfony2：在RedirectResponse中设置Last-Modified

here is what I have:

I have got a route where I call a service to rotate a given image.

/**
 * @Route("/media/rotate/{id}", name="rotate_image")
 *
 * @ParamConverter(name="media", class="RA\MediaBundle\Entity\Media")
 *
 * @param Media $media
 *
 * @return RedirectResponse
 */
public function rotateImage(Media $media)
{
    $this->get('ra.image.rotator.service')->rotateImage($media, 90);

    // do the redirect
}

and here is what I would like to do:

Do a redirect on the route I came from (with the help of referer). This does work, but after the redirect the rotated image isn't displayed, because it is cached.

So I thought setting "Last-Modified" in the header to the current DateTime would force the browser to reload the image. I tried to do it the following way:

    if ($referer = $request->headers->get('referer')) {
        $response = new RedirectResponse($referer);
        $response->setLastModified(new \DateTime());

        return $response;
    }

But unfortunately "Last-Modified" is only set in the header of the rotate_image route, not in the one I got redirected to.

Any idea how to solve this issue?

Edit:

I have "solved" my issue by just adding a version parameter to the media urls like this:

return $mediaUrl . '?v=' . md5($media->getUpdatedAt()->format('Y-m-d H:i:s'));

So after rotating the image I'm updating the media entity so that the version will change and the "new" image will be shown.

Put the logic of the image list in a controller and create sub-requests with twig function "render" like: {{ render(controller('AppBundle:ImageController:index', { 'media': media })) }}

You can create an event listener for "kernel.response". take a look at symfony.com/doc/current/event_dispatcher.html Modify the headers of the response with it. Maybe check last modified timestamp of your image.