Proxy a URL received via GET-parameter

[hendrik]

Hi guys!

I want nginx to serve (proxy) a URL, that i would deliver as a
GET-parameter. For example a request could look like this:
/img?url=http%3A%2F%2Fwww.example.com%2Ffavicon.ico

and nginx now should try to fetch http://www.example.com/favicon.ico
from the parameter "URL" and deliver it to the client.
I need this to deliver some files via SSL that are only available
without it.

Is such a setup possible?

Thank you very much in advance for you help!

Kind regards from Germany!
Hendrik

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,118941,118941#msg-118941