We're using multiple Facebook apps for our product, in V1.0 we used to get the same user id for all apps. We save accounts collection in our db in which we save Facebook id in and creating new accounts for users in which we don't have their FB id already.
Last week we've created a new app, when we started to use it we found out that we're getting a different id for existing users and we're creating a new account for them in our db. (This happened because the new app was created on v2.0 as explained here - https://developers.facebook.com/docs/apps/upgrading#upgrading_v2_0_user_ids)
I read that we can use business manager in order to define all apps and get all the user id for all apps under the same business (https://developers.facebook.com/docs/apps/for-business), but I couldn't find how can I connect these ids to the original id.
I saw a hack that once I have app_scoped_id, I can make a another FB api call to get the original id (Get Facebook User ID from app-scoped User ID) but this means I keep managing the FB ids on our db, is this a good approach? or should I move on to manage the app scope ids? how can I get them for my V1.0 apps before this transition takes place? can I migrate my data in db (when having FB global ids only)? or do I must have a user access token in order to get this info?
Thanks! Ilana
