来自 Firebase 的 .isNewUser 方法总是返回 false

Question

I try to use the isNewUser method of firebase but it returns false all the time. According to what I read it only works with accounts created via the Firebase Console which is my case. The function is called as soon as the user clicks on "connect" and his information is correct.

 func sign_in_handler() {
        if self.email != "" && self.pass != "" {
            Auth.auth().signIn(withEmail: self.email, password: self.pass) { (result, error) in
                if err != nil {
                    self.error = err!.localizedDescription
                    self.alert.toggle()
                    return
                }
                guard let isNew = res?.additionalUserInfo?.isNew else {return}
                print("\nIs new user? \(isNew)\n")
                if newUserStatus == true{
                    UserDefaults.standard.set(true, forKey: "status")
                    NotificationCenter.default.post(name: NSNotification.Name("status"), object: nil)
                }
                else{
                    UserDefaults.standard.set(true, forKey: "status")
                    NotificationCenter.default.post(name: NSNotification.Name("status"), object: nil)
                }
            }
        } else {
            self.error = "Wrong informations."
            self.alert.toggle()
        }
    }

Thanks for your help!

Answer 1

The isNewUser property is only true when the current sign-in happened at the same time as when the account was created. So it only happens after a call to createUser(... and never when calling signIn(... .

The reason for that is that it essentially compares the lastSignInDate and creationDate from the metadata of that user, and the former is set when the account is created. So for user you create in the console, the isNewUser property will actually never be true in your application.

If you want to determine whether the user was recently created, you're better of comparing lastSignInDate and creationDate yourself with whatever you consider "new".

If you want to determine whether you've seen this user before, you'll typically instead want to track their user ID in some backend storage when you first see it.