Workflow on iOS not working correctly

We have implemented our login to use Azure AD B2C as per this example. It works perfectly fine with Android but we’re having some weird issues with iOS (I raised a different but related issue just before Xmas).

Here is the flow on the iOS version of the app.

1. User launches the app and is presented with the Azure AD B2C login screen (correct)
2. User enters their credentials (correct)
3. The app redirects the user back to the login screen (with the username and password fields blank) (wrong)
4. After a few seconds the app then logs them in and navigates them to the main screen

After entering their credentials the user should be immediately navigated to the app main screen, NOT back to the login screen. Once they are logged in, subsequently launching the app correctly logs them in. The problem is only on first login.

After some investigation it seems that this method may be causing the issue.

public override bool OpenUrl(UIApplication app, NSUrl url, NSDictionary options)
{
  AuthenticationContinuationHelper.SetAuthenticationContinuationEventArgs(url);
  return true;
}

According to the docs

this logic is meant to ensure that once the interactive portion of the authentication flow is concluded, the flow goes back to MSAL

But it doesn’t. It redirects the user back to the OnAppearing() method of the login page where it attempts (again) to acquire a token (which it does).

Is there any way to fix the behaviour of this method?

[DominicBurford]

After the sugesiton by @jennyf19 I have refactored our code as follows.

• The app attempts to acquire a token silently in the app OnStart() in App.xaml.cs
• If successful the user is navigated to the Login page (but only to immediately pass-through to the MainPage)
• If unsuccessful the user is navigated to the Login page where they need to enter their credentials. If successful they are navigated to the MainPage.

I have tested this on iOS and Android and all seems to work perfectly.

Many thanks to @jennyf19 for the suggestion and helping me fix this issue 👍

[DominicBurford]

@jennyf19 So it is, I didn’t spot that. I’ll have a look at refactoring the code so as to move the silent call out of the OnAppearing method. Thanks for the update on this.