How to prevent new user registration on Firebase?

问题

Is there any way to turn off more users from signing up on Firebase after I've signed up specific users? For instance, if I only want 10 particular users to be signed up and no more, is there a way to turn off future signups?

回答1:

After some digging, even though this method isn't officially listed in the documentation, I found that you can automatically delete any new user that's created once they have signed up using Cloud Functions and the admin SDK. Here's the code I used to delete any new user the moment they have tried signing up:

  exports.deleteNewUser = functions.auth.user().onCreate((event) => {
  const uid = event.data.uid; // The Firebase user.
  admin.auth().deleteUser(uid)
    .then(function() {
      console.log("Successfully deleted user");
    })
    .catch(function(error) {
      console.log("Error deleting user:", error);
    });
  });

来源：https://stackoverflow.com/questions/49162111/how-to-prevent-new-user-registration-on-firebase