Facebook SDK Login for iOS

Question

Using Facebook's iOS SDK, how does a developer figure out if a user has signed out of his/her account in either Safari/Facebook app? If a developer is saving the access token and expiration date in the app between app launches, is there any flag within the SDK to let the developer know that the phone user has actually signed out/changed accounts? I want a user of my app to have to sign in with the new account if they have changed accounts from a third party app.

The Facebook SDK has a 'isSessionValid' method that you can call, but that method's implementation only checks to see if there is an accesstoken and if the expiration date is past a certain point. It does not check to see if the user has signed off or changed accounts from a different app.

Any ideas?

Answer 1

The current design is that once a user has logged into an ios client app and the app has an auth token, the user is in until the auth token expires or the user uninstalls the FB app (or deletes the app from their device). Suppose you have a server involved where your ios client hands the auth token to the server (they're the same FB app). That server would never know that another FB app on that device had logged out. Your user will probably have to use the logout method in Facebook.m.