How to require authentication in ASP.NET Core 5 Blazor Server Mode with redirect to login

Question

How do I configure BlazorHub endpoint to require authenticated user with automatic redirect to login if not authenticated?

I have tried to configure default authorization policy as well as call RequireAuthenticated on BlazorHub endpoint builder, but I'm still not redirected to login page when I run the Blazor app.

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddRazorPages();
        services.AddServerSideBlazor();

        services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
            .AddCookie(); // added by me
        services.AddAuthorization(options =>
        {
            options.DefaultPolicy = new AuthorizationPolicyBuilder()
                .RequireAuthenticatedUser()
                .Build();
        }); // added by me
    }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Error");
            // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
            app.UseHsts();
        }

        app.UseHttpsRedirection();
        app.UseStaticFiles();

        app.UseRouting();

        app.UseAuthentication(); // added by me
        app.UseAuthorization();  // added by me

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
            endpoints.MapBlazorHub()
                .RequireAuthorization(); // added by me
            endpoints.MapFallbackToPage("/_Host");
        });
    }
}

Answer 1

_host.cshtml is regular Razor Page, not a Blazor Component. Therefore the authenticaton must be required for Razor Pages:

public void ConfigureServices(IServiceCollection services)
{
    services.AddRazorPages();
    services.AddServerSideBlazor();
    services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
        .AddCookie(options =>
        {
            options.LoginPath = "/Auth/Login";
            options.LogoutPath = "/Auth/Logout";
        });
}

// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseEndpoints(endpoints =>
    {
        endpoints.MapRazorPages().RequireAuthorization(); // required
        endpoints.MapBlazorHub().RequireAuthorization(); 
        endpoints.MapFallbackToPage("/_Host");
    });
}

It is simmilar to @MisterMagoo's answer

Answer 2

I did it like this

services.AddRazorPages()
        .AddRazorPagesOptions(options
        => options.Conventions
        .AuthorizeFolder("/")
        );