Checking If user is logged in or not - ios

Question

I'm new to iOS development and to the AWS Amplify framework. I am currently working my way through the Authentication documentation, but it isn't clear how to check the logged-in status of a given user. I only want to display the login form if the user not already logged in. How do I achieve this? There doesn't seem to be any information listed in the docs, and the only resource I found from google applied to a different platform (react).

Answer 1

You need to listen to Auth events and update the state for a flag Eg:isSignedIn which would be initially signed off.
final class UserData: ObservableObject {
#Published var isSignedIn : Bool = false
}
import UIKit
import Amplify
import AmplifyPlugins
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
public let userData = UserData()
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
do {
try Amplify.add(plugin: AWSCognitoAuthPlugin())
try Amplify.configure()
// load data when user is signedin
self.checkUserSignedIn()
// listen to auth events
_ = Amplify.Hub.listen(to: .auth) { (payload) in
switch payload.eventName {
case HubPayload.EventName.Auth.signedIn:
self.updateUI(forSignInStatus: true)
case HubPayload.EventName.Auth.signedOut:
self.updateUI(forSignInStatus: false)
case HubPayload.EventName.Auth.sessionExpired:
self.updateUI(forSignInStatus: false)
default:
break
}
}
} catch {
print("Failed to configure Amplify \(error)")
}
return true
}
func updateUI(forSignInStatus : Bool) {
DispatchQueue.main.async() {
self.userData.isSignedIn = forSignInStatus
}
}
// when user is signed in, fetch its details
func checkUserSignedIn() {
// every time auth status changes, let's check if user is signedIn or not
// updating userData will automatically update the UI
_ = Amplify.Auth.fetchAuthSession { (result) in
do {
let session = try result.get()
self.updateUI(forSignInStatus: session.isSignedIn)
} catch {
print("Fetch auth session failed with error - \(error)")
}
}
}
See the full code here.