In my website I have put up Login with Google, Login with Facebook and Login with Twitter.
But if the same user logs in using different providers, ie. the user first logs in using Facebook and then logs out and then logs in using Google I need to identify that both are the same person.
Currently what I am doing is that if the Facebook and Google accounts has the same email id I combine the accounts. The problem is that if the user is logging in using Twitter I wont be getting their email Id which means I cant uniquely identify them.
Does anyone have any other solution ? Thanks