django display message after POST form submit

I have a page with a POST form, that have a action set to some url.

i.e assume this page url is /form_url/ : ..

The view in /submit_url/ take care of the form data. After this, I want to return the same page of the form with a success message. In the view that take care for the POST form, I use HttpResponseRedirect, in order to "clear" the form data from the browser. But in this way I can't display a message in the form page, unless I do something like:

return HttpResponseRedirect("/form_url/?success=1")

and then check for this parameter in the template. I dont like this way, since if the user refreshes the page, he will still see the success message.

I've noticed that in django admin site, the delete/add of objects does use redirect after POST submit, and still display a success message somehow. How?

I've already briefly seen django "messaging" app, but I want to know how it work first..