How to prevent “You have already authorized this a

Question

I'm learning to integrate facebook login in WP8.1. My problem is that I need facebook to ask me for my credentials every time I press the connect button but it does not do that, it remembers the last log in and prompts "You have already authorized my_app_name". How do I go around this? Is there anyway I can prevent facebook to remember the last login? I've followed THIS tutorial, just fyi

Any help would be really appreciated. Thanks.

Answer 1

The web authentication broker must have enabled single-sign-on that prevents asking credentials the next time it is invoked. This behavior is obtained when a callback URI is not specified in the authentication method of WebAuthenticationBroker.

WebAuthenticationBroker.AuthenticateAsync has 2 overloads - one accepting callback URI and the other not. You can use the one with callback URI and provide the default redirect URL of Facebook (https://www.facebook.com/connect/login_success.html)

Refer this link for details.

Also as Abdulwahab Suleiman - MSFT mentioned in the comment, once Facebook has authorized your app - you have to get it unauthorized for the permissions prompt to be seen again. After authorization you can see your app listed in Facebook (Settings -> apps). You can either remove it from there or revoke the Facebook permission through code.

Answer 2

I figured out the solution to this. When the user taps on the connect to facebook button, I silently call the logout uri using WebAuthenticationBroker.AuthenticateSilentlyAsync. This does not open the UI thread and logs out the previously logged in user before opening the facebook connect dialog.

So essentially every time a user tries to connect my application to facebook, it logs out the previous logged in user before presenting the connect dialog.