Question

I am making a module for a server software that is allowing support for facebook.
The problem is with the callback URL. If one client start the authorization proccess, then another client starts the proccess at the same time, or before the first user finish. How could I check what user finished first?

I need a way to check what client’s callback I’m getting. One solution would be to lock other from register until the first one has finished, but I don’t want to do that. Is there another way? I have thought about including ?client=clientid at the end of the callback, but I heard facebook only allows the exact url specified in the app on facebook.

UPDATE
It didn’t work to add client=”clientid” to the callback. Any other ideas?

Answer 1

After some more searchig I figured facebook will allow a parameter: state. (thanks to @jacob https://stackoverflow.com/a/6470835/1104307)

So I just did ?state=clientId.

For anyone using scribe the code is this:

service.getAuthorizationUrl(null) + "&state=" + clientId;