How to set up to be able to log in through Facebook?

Question

Facebook

On some sites, to log in, you do not need to spend a lot of time and you can do it using the "Login with Facebook or Twitter, etc." buttons. Technically, this is difficult to implement, and is it possible to make a restriction so that only those, for example, who have at least 30 friends in the profile or subscribers, can log in?

Answer 1

Anyone can log in, and then in general the right not to give access according to certain criteria

Answer 2

OAuth2