Vfrdtyky

I want to store users under their Firebase generated uid. When I attempt to use this code:

  func showCredentials() {

        let credential = FacebookAuthProvider.credential(withAccessToken: FBSDKAccessToken.current().tokenString)

        Auth.auth().signInAndRetrieveData(with: credential) { (AuthDataResult, error) in

            if error != nil {

                print("Something went wrong with our Facebook User: ", error)

                return

            }

            print("Successfuly logged in with our Facebook User: ", AuthDataResult)

            self.performSegue(withIdentifier: "FacebookSegue", sender: self)

        }

        FBSDKGraphRequest(graphPath: "/me", parameters: ["fields": "id, name, email"]).start {

            (connection, graphResult, error) in

            if error != nil {

                print("Failed to Start Graph Request:", error)

                return

            }

            print(graphResult)

            let facebookDetail = graphResult as! NSDictionary

            let userID = facebookDetail["id"]

            let fullName = facebookDetail["name"]

            let email = facebookDetail["email"]

            let providerName = "Facebook"

            let userValues = (["Email": email, "Full Name": fullName, "UID": userID, "Provider":providerName])

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

            let key = databaseRef.child("node").childByAutoId().key ?? ""

            let childUpdates = ["/Users/(userID))/": userValues]

            databaseRef.updateChildValues(childUpdates)

            print(userID!)

            print(fullName!)

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

            print(firebaseID!)

        }

    }

The error I am given is: Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value on the line where I am attempting to print the firebaseID. Why is the value of Auth.auth().currentUser?.uid nil and what can I do to obtain this value?

You init 2 asynchronous requests at the same time

Auth.auth().signInAndRetrieveData and FBSDKGraphRequest(graphPath: "/me"

where the second may finish first causing the crash as the auth isn't yet finished , so you need to nest them to be sure that you access the user after the auth signin finishes

func showCredentials() {

    let credential = FacebookAuthProvider.credential(withAccessToken: FBSDKAccessToken.current().tokenString)

    Auth.auth().signInAndRetrieveData(with: credential) { (AuthDataResult, error) in

        if error != nil {

            print("Something went wrong with our Facebook User: ", error)

            return

        }

        FBSDKGraphRequest(graphPath: "/me", parameters: ["fields": "id, name, email"]).start {

        (connection, graphResult, error) in

        if error != nil {

            print("Failed to Start Graph Request:", error)

            return

        }

        print(graphResult)

        let facebookDetail = graphResult as! NSDictionary

        let userID = facebookDetail["id"]

        let fullName = facebookDetail["name"]

        let email = facebookDetail["email"]

        let providerName = "Facebook"

        let userValues = (["Email": email, "Full Name": fullName, "UID": userID, "Provider":providerName])

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

        let key = databaseRef.child("node").childByAutoId().key ?? ""

        let childUpdates = ["/Users/(userID))/": userValues]

        databaseRef.updateChildValues(childUpdates)

        print(userID!)

        print(fullName!)

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

        print(firebaseID!)



        DispatchQueue.main.async {

         print("Successfuly logged in with our Facebook User: ", AuthDataResult)

         self.performSegue(withIdentifier: "FacebookSegue", sender: self)

        }



    }





    }



}