Blazor with AzureAD Auth, Context.Identity.User.Name is null

问题

Only authenticated users can access the application as expected. I need to be able to track users via signalr. For example, if I run a ChatHub type of service, I'd like people to be able to chat using their AzureAD username which should be set automatically and not let people set their own usernames.

The hub always shows Context.Identity.User.Name is null.

    services.AddAuthentication(AzureADDefaults.AuthenticationScheme)
            .AddAzureAD(options => Configuration.Bind("AzureAd", options));

    services.AddTransient<HubConnectionBuilder>();


    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllers();
        endpoints.MapBlazorHub<App>(selector: "app");
        endpoints.MapFallbackToPage("/_Host");
        endpoints.MapHub<SomeHub>("/SomeHub");
    });

Any idea if here is a way to preserve identity information and pass to SignalR?

回答1:

Inspect your JWT token and check its claims. You can past it on http://jwt.ms/ to decode it. Then, look for the claims that are being returned that references the user name (in my case it is preferred_username).

Then you can change the default mapping of the Identity.Name using this code:

services.Configure<OpenIdConnectOptions>(AzureADDefaults.AuthenticationScheme, options =>
{
    options.TokenValidationParameters.NameClaimType = "<claim_name_that_returns_username>";
});

回答2:

My workaround at the moment will be to just pass the username when the connection is created to the hub.

In codebehind (SomePage.razor.cs)

public class SomePageBase : ComponentBase
{
    [Inject]
    private HubConnectionBuilder _hubConnectionBuilder { get; set; }

    [Inject] 
    private AuthenticationStateProvider authProvider { get; set; }

    protected async override Task OnInitializedAsync()
    {
        var user = (await authProvider.GetAuthenticationStateAsync()).User.Identity.Name;
        // in Component Initialization code
        var connection = _hubConnectionBuilder // the injected one from above.
            .WithUrl("https://localhost:44331/SomeHub")
            .Build(); // Build the HubConnection
        await connection.StartAsync();
        var stringResult =
            await connection.InvokeAsync<string>("HubMethodName", user);
    }
}

来源：https://stackoverflow.com/questions/57715882/blazor-with-azuread-auth-context-identity-user-name-is-null

标签

azure-active-directory

signalr

blazor