MAUI

Callback URLs are the URLs that Auth0 invokes after the authentication process. Auth0 routes your application back to this URL and appends additional parameters to it, including an access code which will be exchanged for an ID Token, Access Token, and Refresh Token.

Since callback URLs can be manipulated, you will need to add your application's URL to your application's Allowed Callback URLs for security. This will enable Auth0 to recognize these URLs as valid. If omitted, authentication will not be successful.

Auth0 provides a MAUI SDK to simplify the process of implementing Auth0 authentication in MAUI applications.

Use the NuGet Package Manager (Tools -> Library Package Manager -> Package Manager Console) to install the Auth0.OidcClient.MAUI package.

Alternatively, you can use the Nuget Package Manager Console (Install-Package) or the dotnet CLI (dotnet add).

Install-Package Auth0.OidcClient.MAUI

dotnet add package Auth0.OidcClient.MAUI

You need some platform-specific configuration to use the SDK with Android and Windows.

Create a new Activity that extends WebAuthenticatorCallbackActivity:

[Activity(NoHistory = true, LaunchMode = LaunchMode.SingleTop, Exported = true)]
[IntentFilter(new[] { Intent.ActionView },
              Categories = new[] { Intent.CategoryDefault, Intent.CategoryBrowsable },
              DataScheme = CALLBACK_SCHEME)]
public class WebAuthenticatorActivity : Microsoft.Maui.Authentication.WebAuthenticatorCallbackActivity
{
    const string CALLBACK_SCHEME = "myapp";
}

The above activity will ensure the application can handle the myapp://callback URL when Auth0 redirects back to the Android application after logging in.

To make sure it can properly reactivate your application after being redirected back to Auth0, you need to do two things:

• Add the corresponding protocol to the Package.appxmanifest. In this case, this is set to myapp, but you can change this to whatever you like (ensure to update all relevant Auth0 URLs as well).

  <Applications>
    <Application Id="App" Executable="$targetnametoken$.exe" EntryPoint="$targetentrypoint$">
      <Extensions>
        <uap:Extension Category="windows.protocol">
          <uap:Protocol Name="myapp"/>
        </uap:Extension>
      </Extensions>
    </Application>
  </Applications>

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• Call Activator.Default.CheckRedirectionActivation() in the Windows-specific App.xaml.cs file.

  public App()
  {
    if (Auth0.OidcClient.Platforms.Windows.Activator.Default.CheckRedirectionActivation())
      return;
  
    this.InitializeComponent();
  }

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To integrate Auth0 into your application, instantiate an instance of the Auth0Client class, passing an instance of Auth0ClientOptions that contains your Auth0 Domain, Client ID and the required Scopes. Additionally, you also need to configure the RedirectUri and PostLogoutRedirectUri to ensure Auth0 can redirect back to the application using the URL(s) configured.

using Auth0.OidcClient;

var client = new Auth0Client(new Auth0ClientOptions
{
    Domain = "{yourDomain}",
    ClientId = "{yourDomain}",
    RedirectUri = "myapp://callback",
    PostLogoutRedirectUri = "myapp://callback",
    Scope = "openid profile email"
});

By default, the SDK will leverage Chrome Custom Tabs for Android, ASWebAuthenticationSession for iOS and macOS and use your system's default browser on Windows.

Now that you have configured your Auth0 Application and the Auth0 SDK, you need to set up login for your project. To do this, you will use the SDK’s LoginAsync() method to create a login button that redirects users to the Auth0 Universal Login page.

var loginResult = await client.LoginAsync();

If there isn't any error, you can access the User, IdentityToken, AccessToken and RefreshToken on the LoginResult returned from LoginAsync().

Users who log in to your project will also need a way to log out. Create a logout button using the SDK’s LogoutAsync() method. When users log out, they will be redirected to your Auth0 logout endpoint, which will then immediately redirect them back to the logout URL you set up earlier in this quickstart.

await client.LogoutAsync();

Now that your users can log in and log out, you will likely want to be able to retrieve the profile information associated with authenticated users. For example, you may want to be able to display a logged-in user’s name or profile picture in your project.

The Auth0 SDK for MAUI provides user information through the LoginResult.User property.

if (loginResult.IsError == false)
{
    var user = loginResult.User;
    var name = user.FindFirst(c => c.Type == "name")?.Value;
    var email = user.FindFirst(c => c.Type == "email")?.Value;
    var picture = user.FindFirst(c => c.Type == "picture")?.Value;
}