How to check if user has valid Auth Session Firebase iOS? - ios

Question

I wanna check if the user has still a valid session, before I present the Home View controller of my app. I use the latest Firebase API. I think if I use the legacy, I'll be able to know this.
Here's what I did so far:
I posted my question on Slack community of Firebase, no one is answering. I found this one, but this is for Android: https://groups.google.com/forum/?hl=el#!topic/firebase-talk/4HdhDvVRqHc
I tried reading the docs of Firebase for iOS, but I can't seem to comprehend it: https://firebase.google.com/docs/reference/ios/firebaseauth/interface_f_i_r_auth
I tried typing in Xcode like this:
FIRApp().currentUser()
FIRUser().getCurrentUser()
But I can't seem to find that getCurrentUser function.

Answer 1

if FIRAuth.auth().currentUser != nil {
presentHome()
} else {
//User Not logged in
}
For updated SDK
if Auth.auth().currentUser != nil {
}

Answer 2

Updated answer
Solution for latest Firebase SDK - DOCS
// save a ref to the handler
private var authListener: AuthStateDidChangeListenerHandle?
// Check for auth status some where
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
authListener = Auth.auth().addStateDidChangeListener { (auth, user) in
if let user = user {
// User is signed in
// let the user in?
if user.isEmailVerified {
// Optional - check if the user verified their email too
// let the user in?
}
} else {
// No user
}
}
}
// Remove the listener once it's no longer needed
deinit {
if let listener = authListener {
Auth.auth().removeStateDidChangeListener(authListener)
}
}
Original solution
Solution in Swift 3
override func viewDidLoad() {
super.viewDidLoad()
FIRAuth.auth()!.addStateDidChangeListener() { auth, user in
if user != nil {
self.switchStoryboard()
}
}
}
Where switchStoryboard() is
func switchStoryboard() {
let storyboard = UIStoryboard(name: "NameOfStoryboard", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "ViewControllerName") as UIViewController
self.present(controller, animated: true, completion: nil)
}
Source

Answer 3

Solution in Swift 4
override func viewDidLoad() {
super.viewDidLoad()
setupLoadingControllerUI()
checkIfUserIsSignedIn()
}
private func checkIfUserIsSignedIn() {
Auth.auth().addStateDidChangeListener { (auth, user) in
if user != nil {
// user is signed in
// go to feature controller
} else {
// user is not signed in
// go to login controller
}
}
}

Answer 4

if Auth.auth().currentUser?.uid != nil {
//user is logged in
}else{
//user is not logged in
}

Answer 5

While you can see if there is such a user using Auth.auth().currentUser, this will only be telling you if there was a user authenticated, regardless of whether that users account still exists or is valid.
Complete Solution
The real solution to this should be using Firebase's re-authentication:
open func reauthenticate(with credential: AuthCredential, completion: UserProfileChangeCallback? = nil)
This assures (upon the launch of the application) that the previously signed in / authenticated user still in fact is and can be authenticated through Firebase.
let user = Auth.auth().currentUser // Get the previously stored current user
var credential: AuthCredential
user?.reauthenticate(with: credential) { error in
if let error = error {
// An error happened.
} else {
// User re-authenticated.
}
}

Answer 6

override func viewDidLoad() {
FIRAuth.auth()!.addStateDidChangeListener() { auth, user in
// 2
if user != nil {
let vc = self.storyboard?.instantiateViewController(withIdentifier: "Home")
self.present(vc!, animated: true, completion: nil)
}
}
}
Source: https://www.raywenderlich.com/139322/firebase-tutorial-getting-started-2

Answer 7

An objective-c solution would be (iOS 11.4):
[FIRAuth.auth addAuthStateDidChangeListener:^(FIRAuth * _Nonnull auth, FIRUser * _Nullable user) {
if (user != nil) {
// your logic
}
}];

Answer 8

All the provided answers only check on currentUser. But you could check the auth session by simple user reload like below:
// Run on the background thread since this is just a Firestore user reload, But you could also directly run on the main thread.
DispatchQueue.global(qos: .background).async {
Auth.auth().currentUser?.reload(completion: { error in
if error != nil {
DispatchQueue.main.async {
// Authentication Error
// Do the required work on the main thread if necessary
}
} else {
log.info("User authentication successfull!")
}
})
}