User variable is nil when creating a user with Firebase - ios

Question

I am following a tutorial and cannot seem to register my user as the user variable in the Firebase .createUser method appears to be nil. Therefore, when I unwrap it, I get an error.
I have read through a lot of the documentation as well as checked many other questions similar to mine but nothing seems to work
import UIKit
import Firebase
import SwiftKeychainWrapper
class ViewController: UIViewController {
#IBOutlet weak var userImgView: UIImageView!
#IBOutlet weak var usernameField: UITextField!
#IBOutlet weak var emailField: UITextField!
#IBOutlet weak var passwordField: UITextField!
var imagePicker: UIImagePickerController!
var selectedImage: UIImage!
override func viewDidLoad() {
super.viewDidLoad()
imagePicker = UIImagePickerController()
imagePicker.allowsEditing = true
imagePicker.delegate = self
}
override func viewDidAppear(_ animated: Bool) {
if let _ = KeychainWrapper.standard.string(forKey: "uid") {
self.performSegue(withIdentifier: "toFeed", sender: nil)
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func setupUser(userUid: String) {
if let imageData = self.userImgView.image!.jpegData(compressionQuality: 0.2) {
let imgUid = NSUUID().uuidString
let metaData = StorageMetadata()
Storage.storage().reference().child(imgUid).putData(imageData, metadata: metaData) { (metadata, error) in
let downloadURL = metadata
let userData = [
"username": self.usernameField.text!,
"userImg": downloadURL!
] as [String : Any]
Database.database().reference().child("users").child(userUid).setValue(userData)
self.performSegue(withIdentifier: "toFeed", sender: nil)
}
}
}
#IBAction func signInPressed(_ sender: Any) {
if let email = emailField.text, let password = passwordField.text {
Auth.auth().signIn(withEmail: email, password: password) { user, error in
if error != nil && !(self.usernameField.text?.isEmpty)! {
Auth.auth().createUser(withEmail: email, password: password) { (user, error) in
self.performSegue(withIdentifier: "toFeed", sender: nil)
let userID = (user?.user.uid)!
self.setupUser(userUid: userID)
KeychainWrapper.standard.set(userID, forKey: "uid")
}
} else {
if let userID = (user?.user.uid) {
KeychainWrapper.standard.set((userID), forKey: "uid")
self.performSegue(withIdentifier: "toFeed", sender: nil)
}
}
}
}
}
#IBAction func getPhoto (_ sender: AnyObject) {
present(imagePicker, animated: true, completion: nil)
}
}
extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
internal func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
if let image = info[.originalImage] as? UIImage {
userImgView.image = image
} else {
print("image wasnt selected")
}
imagePicker.dismiss(animated: true, completion: nil)
}
}
The error I am getting is one the "let userID = (user?.user.uid)!". It is
Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)

Answer 1

The completion block for createUser(withEmail:,password:) gets called with either a AuthResult.user or an error. That why, as Joshua commented, you should check if error is nil before accessing any of the user properties.
From the auth quickstart for Swift:
Auth.auth().createUser(withEmail: email, password: password) { authResult, error in
strongSelf.hideSpinner {
guard let user = authResult?.user, error == nil else {
strongSelf.showMessagePrompt(error!.localizedDescription)
return
}
print("\(user.email!) created")
strongSelf.navigationController?.popViewController(animated: true)
}
}