I'm working on a project that involves a native iOS client as well as a web back end (a Padrino app, if it matters). I've got Facebook authentication working fine for either one individually; but what I would like if at all possible is for the user to login using the native app using Facebook's iOS SDK, and then for this authentication to somehow make it all the way to my servers. The alternative seems to be to require the user to log in twice with Facebook, which I'm sure can't be right.
Is this possible? Alternately, what is the standard way to solve this problem?