Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.SpaServices.Webpack;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;

namespace test
{
    public class Startup
    {
        public Startup(IHostingEnvironment env, IConfiguration configuration)
        {
            Configuration = configuration;
            Environment = env;
        }

        public IConfiguration Configuration { get; }
        public IHostingEnvironment Environment { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();

            services.AddAuthentication(options =>
            {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;

            }).AddJwtBearer(o =>
            {
                o.Authority = Configuration["Jwt:Authority"];
                o.Audience = Configuration["Jwt:Audience"];
                o.RequireHttpsMetadata = false;

                o.Events = new JwtBearerEvents()
                {
                    OnAuthenticationFailed = c =>
                    {
                        c.NoResult();

                        c.Response.StatusCode = 500;
                        c.Response.ContentType = "text/plain";

                        if (Environment.IsDevelopment())
                        {
                            return c.Response.WriteAsync(c.Exception.ToString());
                        }

                        return c.Response.WriteAsync("An error occured processing your authentication.");
                    }
                };
            });

            services.AddAuthorization(options =>
            {
                options.AddPolicy("Administrator", policy => policy.RequireClaim("user_roles", "[Administrator]"));
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseWebpackDevMiddleware(new WebpackDevMiddlewareOptions
                {
                    HotModuleReplacement = true
                });
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }

            app.UseStaticFiles();

            app.UseAuthentication();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");

                routes.MapSpaFallbackRoute(
                    name: "spa-fallback",
                    defaults: new { controller = "Home", action = "Index" });
            });
        }
    }
}