Problems generating Rails route for weird URL

I have a URL that looks like this:

http://ift.tt/1O065Wu

I need to generate a rails route for this such that I can get namespace.001.587 out as the id and get it to route to the ImageViewer#show_image action, I also need to get 2down as the mode, and 1 as the page. Not being a clean RESTful URL, I'm finding this difficult to do in Rails. I'm only calling GET on this URL.

How would you generate this route?