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Tutorial: Support web fallback in Android app

  • Artikkeli

This tutorial demonstrates how isBrowserRequired() error happens and how you can resolve it. The utility method isBrowserRequired() checks the need for a fallback mechanism for various scenarios where native authentication isn't sufficient to complete the authentication flow in functional and safe manner.

In this tutorial, you learn how to:

  • Check isBrowserRequired()
  • Handle isBrowserRequired()

Prerequisites

Web fallback

Use web fallback mechanism for scenarios where native authentication isn't sufficient to complete the user authentication flow.

When you initialize the Android SDK, you specify the challenge types your mobile application supports, such as oob and password.

If your client app can't support a challenge type that Microsoft Entra requires, Microsoft Entra's response indicates that the client app needs to continue with the authentication flow in the browser. For example, you initialize the SDK with oob challenge type, but in the Microsoft Entra admin center you configure the app with an email with password authentication method.

In this case, the utility method isBrowserRequired() returns true.

Sample flow

Let's look at an example flow that returns isBrowserRequired(), and how you can handle it:

  1. In the JSON configuration file, which you pass to the SDK during initialization, add only the oob challenge type as shown the following code snippet:

    PublicClientApplication.createNativeAuthPublicClientApplication( 
    requireContext(), 
    R.raw.native_auth_config  // JSON configuration file 
)

    The native_auth_config.json configuration has the following code snippet:

    {
  "client_id" : "{Enter_the_Application_Id_Here}",
   "authorities" : [
    {
      "type": "CIAM",
      "authority_url": "https://{Enter_the_Tenant_Subdomain_Here}.ciamlogin.com/{Enter_the_Tenant_Subdomain_Here}.onmicrosoft.com/"
    }
  ],
  "challenge_types" : ["oob"],
  "logging": {
    "pii_enabled": false,
    "log_level": "INFO",
    "logcat_enabled": true
  }
}

  2. In the Microsoft Entra admin center, configure your user flow to use Email with password as the authentication method.

  3. Start a sign-up flow by using the SDK's signUp(username) method. You get a SignUpError that passes the isBrowserRequired() check as Microsoft Entra expects password and oob challenge type, but you configured your SDK with only oob.

  4. To check and handle the isBrowserRequired(), use the following code snippet:

    val actionResult = authClient.signUp( 
    username = email 
) 
if (actionResult is SignUpError && actionResult.isBrowserRequired()) { 
    // Handle "browser required" error
}

    The code indicates that the authentication flow can't be completed through native authentication, and that a browser has to be used.

Handle isBrowserRequired() error

To handle this error, the client app need to launch a browser and restart the authentication flow. You can accomplish by using Microsoft Authentication Library (MSAL) acquireToken() method.

To do so, use the following steps:

  1. To add a redirect URI to the app that you registered earlier, use the steps in Add a platform redirect URL.

  2. To update your client app's configuration file, use the steps in Configure the redirect URI in SDK's configuration.

  3. Use the following code snippet to acquire a token by using the acquireToken() method:

    val actionResult = authClient.signUp(
    username = email
)
if (actionResult is SignUpError && actionResult.isBrowserRequired()) {
    authClient.acquireToken(
        AcquireTokenParameters(
            AcquireTokenParameters.Builder()
                .startAuthorizationFromActivity(requireActivity())
                .withScopes(getScopes())
                .withCallback(getAuthInteractiveCallback())
        )
        // Result will contain account and tokens retrieved through the browser.
    )
}

Security tokens, that's ID token, access token and refresh token, you get through native authentication flow are same as the token you get via browser-delegated flow.

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