JWT(JSON WEB TOKEN) Authentication and Authorization in asp net core 2 1 with example

JWT(JSON WEB TOKEN) Authentication and Authorization in asp net core 2 1 with the example

Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication.JwtBearer;
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.Logging;
using Microsoft.Extensions.Options;
using Microsoft.IdentityModel.Tokens;

namespace JWTEx
{
    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(JwtBearerDefaults.AuthenticationScheme)
 .AddJwtBearer(options =>
 {
     var serverSecret = new SymmetricSecurityKey(Encoding.UTF8.
GetBytes(Configuration["JWT:key"]));
     options.TokenValidationParameters = new
    TokenValidationParameters
     {
         IssuerSigningKey = serverSecret,
         ValidIssuer = Configuration["JWT:Issuer"],
         ValidAudience = Configuration["JWT:Audience"]
     };
 });

           

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            app.UseAuthentication();
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseHsts();
            }
            
            app.UseHttpsRedirection();
            app.UseMvc();
        }
    }
}

TokenController

using System;
using System.Collections.Generic;
using System.IdentityModel.Tokens.Jwt;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.IdentityModel.Tokens;

namespace JWTEx.Controllers
{
    [Route("api/[controller]")]
    public class TokenController : Controller
    {
        private IConfiguration _config;

        public TokenController(IConfiguration config)
        {
            _config = config;
        }
        [AllowAnonymous]
        [HttpPost]
        public IActionResult CreateToken([FromBody]LoginModel login)
        {
            IActionResult response = Unauthorized();
            var user = Authenticate(login);

            if (user != null)
            {
                var tokenString = BuildToken(user);
                response = Ok(new { token = tokenString });
            }

            return response;
        }
        private string BuildToken(UserModel user)
        {
            var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_config["Jwt:Key"]));
            var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);

            var token = new JwtSecurityToken(_config["Jwt:Issuer"],
              _config["Jwt:Issuer"],
              expires: DateTime.Now.AddMinutes(30),
              signingCredentials: creds);

            return new JwtSecurityTokenHandler().WriteToken(token);
        }
        private UserModel Authenticate(LoginModel login)
        {
            UserModel user = null;

            if (login.Username == "mario" && login.Password == "secret")
            {
                user = new UserModel { Name = "Mario Rossi", Email = "mario.rossi@domain.com" };
            }
            return user;
        }
        public class LoginModel
        {
            public string Username { get; set; }
            public string Password { get; set; }
        }

        private class UserModel
        {
            public string Name { get; set; }
            public string Email { get; set; }
            public DateTime Birthdate { get; set; }
        }
    }
}

Values Controller

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace JWTEx.Controllers
{
  
   
    [Route("api/[controller]")]
    [ApiController]
    
    public class ValuesController : ControllerBase
    {
        // GET api/values
        [HttpGet, Authorize]
        public IEnumerable<Book> Get()
        {
            var currentUser = HttpContext.User;
            var resultBookList = new Book[] {
        new Book { Author = "Ray Bradbury",Title = "Fahrenheit 451" },
        new Book { Author = "Gabriel García Márquez", Title = "One Hundred years of Solitude" },
        new Book { Author = "George Orwell", Title = "1984" },
        new Book { Author = "Anais Nin", Title = "Delta of Venus" }
      };

            return resultBookList;
        }
        public class Book
        {
            public string Author { get; set; }
            public string Title { get; set; }
            public bool AgeRestriction { get; set; }
        }
        // GET api/values/5
        [HttpGet("{id}")]
        public ActionResult<string> Get(int id)
        {
            return "value";
        }

        // POST api/values
        [HttpPost]
        public void Post([FromBody] string value)
        {
        }

        // PUT api/values/5
        [HttpPut("{id}")]
        public void Put(int id, [FromBody] string value)
        {
        }

        // DELETE api/values/5
        [HttpDelete("{id}")]
        public void Delete(int id)
        {
        }
    }
}

appsettings.json

{
  "Jwt": {
    "key": "veryVerySecretKey",
    "Issuer": "https://localhost:44359/",
    "Audience": "https://localhost:44359/"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Warning"
    }
  },
  "AllowedHosts": "*"
}