Current User UID different than Auth UID?

Question

Warning: Im very new to coding in general and xcode

Running Xcode 8.2

Anyways, So I have saved my users authentication details, email password. And I save them under user/currentUser.UID and it gives username and email. I want to retrieve the username and put it as a label text but the UID's are different?!

Grab username through database and set a label to the username

@IBOutlet weak var welcomeHomeUsername: UILabel!

func welcomeHomeAddUsername() {


    guard let uid12 = Auth.auth().currentUser?.uid else {
        return
    }

    print("User ID post guard: \(uid12)")

    ref.child("users").child(uid12).child("username").observeSingleEvent(of: .value, with: { snapshotWelcome in

        print(snapshotWelcome)
        let welcomeHomeUser = snapshotWelcome.value as? String
        self.welcomeHomeUsername.text = welcomeHomeUser

    })

}

Then this is the code to allow users to sign up with firebase auth and then saves the username and email values in /users/(uid)/

@IBAction func signUpButton(_ sender: Any)
{


    //Authenticate User//
    Auth.auth().createUser(withEmail: emailTextField.text!, password: passwordTextField.text!) { (user, error) in

        if user != nil {
            print("User Created")
                self.performSegue(withIdentifier: "backLogin", sender: self)
        }
        else {
            print("error no seg")
        }
    }
    //Successfully Authenticated User//




    guard let uid = Auth.auth().currentUser?.uid else {
        return
    }



    //Add User to Database//
    let ref = Database.database().reference(fromURL: "~~~My Database URL~~~")
    let usersReference = ref.child("users").child(uid)
    let values = ["username": usernameTextField.text, "email": emailTextField.text]
    usersReference.updateChildValues(values) { (err, ref) in

        if err != nil {
            print("error no user created")
        }

        if (Auth.auth().currentUser != nil){
            print("user id: " + (Auth.auth().currentUser?.uid)!);
            return
        }
        print("Saved user succesfully into Firebase DB")


    }


}

Then in my console output

    user id: mrsIBAAl2LVb7FetVxnMwBtMJ562

    User ID post guard: 0QkYbdPdH7QdZsdRjck53l4Ekrk2
    Snap (message1) Welcome to the Beta!
    Snap (username) <null>

I also have a function that gets the MOTD which right now is "welcome to the test!" and that is a branch in my database which I reference in a different function but I don't think that should make a difference.

Answer 1

EUREKA! I found the problem!

I looked through the flow of my sign up and was testing different parts of it when I noticed that the UID in the database was the past UID that was the auth, so when a new auth UID was made the old one showed up in the database. I looked through the flow using console prints and found that the authentication and creation of the user was happening AFTER the database was logging the user! So to fix this, I put my authentication in its own function, then at the end of that once the user was authenticated, I called the function that adds the user to the databases and this works!

@IBAction func signUpButton(_ sender: Any)
{

    signupTrue = 0
    print(signupTrue)

    let ref3 = Database.database().reference()

    ref3.child("schools").observeSingleEvent(of: .value, with: { (snapshot) in

        if snapshot.hasChild(self.schoolNameTextfield.text!){
            print("true school exist")
            signupTrue = 1
            print(signupTrue)

            self.authUserFunc()

        }
        else {
            print("false school doesn't exist")
            signupTrue = 2
            print(signupTrue)
        }
    })
    print("Test ending ref3")
}



func authUserFunc() {

    //Authenticate User//
    Auth.auth().createUser(withEmail: emailTextField.text!, password: passwordTextField.text!) { (user, error) in

        if user != nil {
            print("User Created")
            self.performSegue(withIdentifier: "backLogin", sender: self)
            self.addToDatabase()
        }
        else {
            print("error no seg")
        }
    }
    //Successfully Authenticated User//

}




func addToDatabase() {
    print("Starting add to database")
        print("starting signup")


        //Add User to School Database//
        let ref = Database.database().reference(fromURL: "~~~My Database URL~~~")
        let userSchoolReference = ref.child("schools").child(schoolNameTextfield.text!).child("users").child("\(Auth.auth().currentUser!.uid)")
        let values = ["username": usernameTextField.text!, "email": emailTextField.text!]
        userSchoolReference.updateChildValues(values) { (err, ref) in


            if err != nil {
                print("error no school user created")
            }

            if (Auth.auth().currentUser != nil){
                print("Saved user succesfully into School Firebase DB")
                //print("user id: " + (Auth.auth().currentUser?.uid)!);
                return
            }
        }



        //add user to users file//
        //let userReference = ref.child("users").child("\(Auth.auth().currentUser!.uid)")
        let values2 = ["username": usernameTextField.text!, "email": emailTextField.text!, "password": passwordTextField.text!]


    Database.database().reference().child("users").child("\(Auth.auth().currentUser!.uid)").updateChildValues(values2) { (err, ref) in
        if err != nil{
            print("Error no user created")
            return
        }
    }

    print("\(Auth.auth().currentUser?.uid)")

//end func addToDatabase
}

Thank you for all your help! I think now that I am over this bump, ill be able to move forward with my coding with more knowledge!