I\'m developing a Facebook application using their Graph API. I have previously developed an app using the deprecated REST API.
I\'ve come across a problem in that
That is a good question.
The problem is that any application run under facebook has to go through facebook servers - fb proxy and because of this the IP you get is not that of visitors but facebook's servers' instead which is of no use.
I have not seen any solution for this yet except for getting user's country from his profile which again is only possible if user had made it public or authorized the permission for it.
Here is useful link you might want to check out there too: