Devise Omniauth and Iphone/Android App

Alright, so I'm answering my own question.

If you use the Facebook SDK, the SSO works quite good on the device, BUT, the token you receive is not the same as the one you're gonna receive on your Rails App. Apparently Facebook creates different tokens depending on the support.

So what I did was: Once I receive the token on the Android device, I send it to my rails app via the url:

http://myapp/check_mobile_login?token=FB_MOBILE_TOKEN

This is then caught by my Application controller, which uses the Token with the fb_graph gem to fetch user data. If the Token is valid I'm going to receive some pieces of information. I then check with my database, and, if I find the same UID, then my user is authenticated and I send him back the Authentificable_token from Devise.

And the draft code :

    def check_mobile_login        token = params[:token]        user = FbGraph::User.me(token)        user = user.fetch        logged = User.find_by_uid(user.identifier)        respond_to do |format|            format.html # index.html.erb            format.json { render :json => logged.authentication_token }        end    end

If anyone has a better solution, I would be glad to hear that :)