[Engineer at Firebase] While the uid
parameter is on the token generated and returned to the Firebase Simple Login iOS client, and available in the security rules via the auth
variable, it looks like we're not currently exposing this on the User
object returned to your methods.
Update 2014/03/07: Support for the uid
has been added to the Firebase Simple Login iOS Client as of v1.3.0, available at https://cdn.firebase.com/ios/FirebaseSimpleLogin.framework-1.3.0.zip.
I'll work on adding that functionality for the next version of the Firebase Simple Login iOS client, but in the meantime you can use <provider>:<user-id>
to simulate what the client is doing. I'll update this item once this feature has been added.