使用Facebook登录的移动应用-如何验证用户身份

Question

This is kind of a follow-up to this question: Android Facebook login and to web server

Imagine a mobile app is uninstalled and then installed again or a user gets a new phone and installs the app from scratch. Next, the user logs in to FB and the app receives a fresh FB access_token .

The next step is to send a "sign in" HTTP request to the backend - but we only have a fresh FB token and nothing else so the backend cannot know right away that it should log in an existing user.

So am I right that the backend has to hit FB API on each & every such "sign in" request from a mobile, as it can never know if it's a brand new user trying to sign up or an existing user trying to sign in?

Answer 1

您拥有可以使用60天的长期令牌https://developers.facebook.com/docs/facebook-login/access-tokens/