Add authentication to SwaggerUI

Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authentication.OpenIdConnect;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace SwashbuckleAuthentication
{
    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
                .AddAuthentication(options =>
                {
                    options.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                    options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
                })
                .AddCookie()
                .AddOpenIdConnect(options =>
                {
                    options.Authority = "https://demo.identityserver.io";
                    options.ClientId = "interactive.confidential";
                    options.ClientSecret = "secret";
                    options.ResponseType = "code";
                    options.SaveTokens = true;
                })
                .Services
                .AddSwaggerGen()
                .AddControllers();
        }

        // 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();
            }
            app.UseAuthentication();

            app.Use(async (context, next) =>
            {
                if (context.Request.Path.StartsWithSegments("/swagger", StringComparison.OrdinalIgnoreCase)
                    && !context.User.Identity.IsAuthenticated)
                {
                    await context.ChallengeAsync();
                    return;
                }

                await next();
            });

            app.UseSwagger();
            app.UseSwaggerUI(setup => setup.SwaggerEndpoint("/swagger/v1/swagger.json", "v1.0"));

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}