Phone authentication using cloud firestore in ios swift?

Question

In my app i am using phone authentication for login and storing user logged in user phone number and uid in database. when login with existing user phone number, it creates new document id with same uid and phone number you can look out the image 1 and 3.

Here is the code i used to login and if user exist mean it should check and navigate to home controller else sign user detail controller.

     @IBAction func loginbtn(_ sender: UIButton) {

    let defaults = UserDefaults.standard
    let credential: PhoneAuthCredential = PhoneAuthProvider.provider().credential(withVerificationID: defaults.string(forKey: "authVID")!,
                                                                                  verificationCode: otpText.text!)
    Auth.auth().signIn(with: credential)
    {
        (user, error) in
        if error != nil
        {
            print("error: \(String(describing: error?.localizedDescription))")
        }
        else if user != nil
        {


            print("Phone number: \(String(describing: user?.phoneNumber))")
            let userInfo = user?.providerData[0]
            print("Provider ID: \(String(describing: userInfo?.providerID))")

            let currentUser = Auth.auth().currentUser?.uid
            var ref: DocumentReference? = nil


            ref = self.db.collection("Users").addDocument(data: [
                                    "phoneNumber"   : user?.phoneNumber as Any,
                                    "UID"           : user?.uid as Any

                                ]) { err in
                                    if let err = err {

                                        print("Error adding document: \(err)")

                                    } else {

                                        print("Document added with ID: \(ref!.documentID)")

                                    }
                                }

            let storyboard = UIStoryboard(name: "Main", bundle: nil)
            let controller = storyboard.instantiateViewController(withIdentifier: "HomeViewController")
            self.present(controller, animated: true, completion: nil)


        } else {




            }


        }

    }

can anyone help me out of this, i am nearly struggling with past one day!!!

Answer 1

You are calling the function "add" which creates a new document assigning an auto generated ID as mentioned here. Instead you'd need to be calling the function "set" using the user's uid as key, like follows:

db.collection("users").doc(uid).set... 

Answer 2

You can also go with the firebase generated UID. You already have that line, but haven't used it:

let currentUser = Auth.auth().currentUser?.uid

So try to replace "UID": user?.uid as Any with "UID": currentUser as Any