Startup.cs

using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Rewrite;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace Fido2Demo
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddRazorPages(opts =>
            {
                // we don't care about antiforgery in the demo
                opts.Conventions.ConfigureFilter(new IgnoreAntiforgeryTokenAttribute());
            });

            // Use the in-memory implementation of IDistributedCache.
            services.AddMemoryCache();
            services.AddDistributedMemoryCache();

            services.AddSession(options =>
            {
                // Set a short timeout for easy testing.
                options.IdleTimeout = TimeSpan.FromMinutes(2);
                options.Cookie.HttpOnly = true;
                // Strict SameSite mode is required because the default mode used
                // by ASP.NET Core 3 isn't understood by the Conformance Tool
                // and breaks conformance testing
                options.Cookie.SameSite = SameSiteMode.Unspecified;
            });

            services.AddFido2(options =>
            {
                options.ServerDomain = Configuration["fido2:serverDomain"];
                options.ServerName = "FIDO2 Test";
                options.Origins = Configuration.GetSection("fido2:origins").Get<HashSet<string>>();
                options.TimestampDriftTolerance = Configuration.GetValue<int>("fido2:timestampDriftTolerance");
                options.MDSCacheDirPath = Configuration["fido2:MDSCacheDirPath"];
            })
            .AddCachedMetadataService(config =>
            {
                config.AddFidoMetadataRepository(httpClientBuilder =>
                {
                    //TODO: any specific config you want for accessing the MDS
                });
            });
        }

        // 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");
                app.UseRewriter(new RewriteOptions().AddRedirectToWWwIfPasswordlessDomain());
            }

            app.UseSession();
            app.UseStaticFiles();
            app.UseRouting();
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapFallbackToPage("/", "/overview");
                endpoints.MapRazorPages();
                endpoints.MapControllers();
            });
        }
    }
}