Web Apps

Microsoft identity web supports ASP.NET Core web apps that sign-in users in Microsoft Entra ID, Azure AD B2C, and Microsoft Entra External IDs. Optionally these apps can call downstream web APIs. Web apps typically run on a server and serve HTML pages.

See:

• Create a new ASP.NET Core web app using the command line, or the Visual Studio wizard.
• Add authentication to an existing web app
• Migrate an ASP.NET Core 3.1 web app to use Microsoft Identity Web

You can enable your web app to allow users to sign up and create a new guest account. First, set up your tenant and the app as described in Add a self-service sign-up user flow to an app. Next, set Prompt property in OpenIdConnectOptions (or in MicrosoftIdentityOptions which inherits from it) to "create" to trigger the sign-up experience. Your app can have a Sign up button linking to an Action which sets the Prompt property, like in the example below. After the user goes through the sign-up process, they will be logged into the app.

[HttpGet("{scheme?}")]
public IActionResult SignUp([FromRoute] string scheme)
{
    scheme ??= OpenIdConnectDefaults.AuthenticationScheme;
    var parameters = new Dictionary<string, object>
    {
        { "prompt", "create" },
    };
    OAuthChallengeProperties oAuthChallengeProperties = new OAuthChallengeProperties(new Dictionary<string, string>(), parameters);
    oAuthChallengeProperties.RedirectUri = Url.Content("~/");

    return Challenge(
        oAuthChallengeProperties,
        scheme);
}

AddMicrosoftIdentityWebApp (applied to authentication builders) has another override, which takes delegates instead of a configuration section. The override with a configuration section actually calls the override with delegates. See the source code for AddMicrosoftIdentityWebApp with configuration section

In advanced scenarios you might want to add configuration by code, or if you want to subscribe to OpenIdConnect events. For instance if you want to provide a custom processing when the token is validated, you could use code like the following:

services.AddAuthentication(OpenIdConnectDefaults.AuthenticationScheme)
        .AddMicrosoftIdentityWebApp(options =>
{
    Configuration.Bind("AzureAD", options);
    options.Events ??= new OpenIdConnectEvents();
    options.Events.OnTokenValidated += OnTokenValidatedFunc;
});

with OnTokenValidatedFunc like the following:

private