Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using JwtTokenDemo.Middlewares;
using JwtTokenDemo.Model;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Tokens;
using Swashbuckle.AspNetCore.Swagger;

namespace JwtTokenDemo
{
    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)
        {
            //Aggiungiamo il supporto a Jwt Bearer Token ai meccanismi
            //di autenticazione supportati dal middleware di ASP.NET Core Identity
            services.AddAuthentication(options => {
                options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
            }).AddJwtBearer(options => {
                options.TokenValidationParameters = new TokenValidationParameters{
                    ValidateIssuer = true,
                    ValidateAudience = true,
                    ValidateIssuerSigningKey = true,
                    ValidIssuer = "Issuer",
                    ValidAudience = "Audience",
                    IssuerSigningKey = new SymmetricSecurityKey(
                        Encoding.UTF8.GetBytes("MiaChiaveSegreta")
                    ),
                    ClockSkew = TimeSpan.Zero
                };
            });

            services.AddSwaggerGen(config =>
            {
                //Necessario per abilitare l'autenticazione con JWT Token da Swagger UI
                config.DocumentFilter<DocumentFilter>();
                config.SwaggerDoc("v1", new Info { Title = "My API", Version = "v1" });
                config.AddSecurityDefinition("JWT Bearer Token", new ApiKeyScheme()
                {
                    Description = "Nella casella sottostante digita <code>Bearer</code> seguito da uno spazio e dal token ottenuto da /api/Token. Esempio: <strong><code>Bearer eyJhbGci...</code></strong><br><br><br><br>",
                    Name = "Authorization",
                    In = "header",
                    Type = "apiKey"
                });
            });

            services.AddMvc();
        }

        // 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.UseMiddleware<JwtTokenMiddleware>();
            app.UseAuthentication();

            // Enable middleware to serve generated Swagger as a JSON endpoint.
            app.UseSwagger();

            // Enable middleware to serve swagger-ui (HTML, JS, CSS, etc.), specifying the Swagger JSON endpoint.
            app.UseSwaggerUI(c =>
            {
                c.SwaggerEndpoint("/swagger/v1/swagger.json", "My API V1");
            });

            app.UseMvc();
        }
    }
}