KenJwtAuth 1.1.0

Ken Jwt Auth

KenJwtAuth provides a way to generate basic bearer token with required claims. It's easy to setup with Asp.net core Identity.

Step 1: Create Project

Create Asp.net core 2.1 project with Individual User Accounts.

Step 2: Add JSON Configuration

Add following json in appsettings.json

"Bearer": {
    "SecretKey": "your secret key",
    "Issuer": "your issuer",
    "Audience": "your audience"
  }

Step 3: Add KenJwtAuth

Install the package using package manager console

Install-Package KenJwtAuth

Or using dot net CLI

dotnet add package KenJwtAuth

Step 4: Setup Token Handler in Startup.cs

Add following code snippet in startup.cs in method ConfigureServices

//Adds database context with Sql Server
services.AddDbContext<ApplicationDbContext>(options =>
	options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
//Adding Identity with DbContext
services.AddDefaultIdentity<IdentityUser>()
	.AddEntityFrameworkStores<ApplicationDbContext>();
//Adding JwtBearer with TokenHandler
services.AddAuthentication()
	.AddJwtBearerWithTokenHandler(JwtBearerDefaults.AuthenticationScheme, jwtOptions =>
	{
		jwtOptions.TokenValidationParameters = new TokenValidationParameters
		{
			ValidateIssuer = true,
			ValidateAudience = true,
			ValidateLifetime = true,
			ValidateIssuerSigningKey = true,
			ClockSkew = TimeSpan.Zero,
			ValidIssuer = Configuration.GetSection("Bearer:Issuer").Value,
			ValidAudience = Configuration.GetSection("Bearer:Audience").Value,
			IssuerSigningKey = new SymmetricSecurityKey(
                Encoding.ASCII.GetBytes(Configuration.GetSection("Bearer:SecretKey").Value)),
        };
        jwtOptions.IncludeErrorDetails = true;
        jwtOptions.SaveToken = true;
    },expiry:DateTime.Now.AddDays(3));

Step 5: Get ITokenHandler from DI

Create an account controller and get ITokenHandler from Dependency Injection.

private readonly UserManager<IdentityUser> _userManager;
private readonly SignInManager<IdentityUser> _signInManager;
private readonly ITokenHandler _tokenHandler;
//Getting ITokenHandler from DI
public AccountController(UserManager<IdentityUser> userManager,
                         SignInManager<IdentityUser> signInManager,
                         ITokenHandler tokenHandler)
{
    _userManager = userManager;
    _signInManager = signInManager;
    _tokenHandler = tokenHandler;
}

Step 6: Create Login and Signup Actions

Create Login and signup action.

[HttpPost("[action]")]
public async Task<IActionResult> SignIn([FromBody] LoginModel model)
{
    var user = await _userManager.FindByEmailAsync(model.Email);
    if (user == null)
    {
        ModelState.AddModelError("email", $"No user exists with email {model.Email}");
        return BadRequest(ModelState);
    }
    var result = await _signInManager.CheckPasswordSignInAsync(user, model.Password, false);
    if (result.Succeeded)
    {
        //Getting token with specified claims.
        var token = _tokenHandler.GenerateTokenForUser(user, claims=>
        {
        	claims.Add(new Claim(ClaimTypes.Email, user.Email));
        });
        return Ok(new { token, user.UserName });
    }
    ModelState.AddModelError("password", $"Invalid password");
    return BadRequest(ModelState);
}

[HttpPost("[action]")]
public async Task<IActionResult> Register([FromBody] RegisterModel model)
{
    var user = await _userManager.FindByEmailAsync(model.Email);
    if (user != null)
    {
        ModelState.AddModelError("email", $"User already exists with email {model.Email}");
        return BadRequest(ModelState);
    }
    var myuser = new IdentityUser { UserName = model.UserName, Email = model.Email };
    var SignUpresult = await _userManager.CreateAsync(myuser, model.Password);
    if (SignUpresult.Succeeded)
    {
        return Ok(new { data = "Signup successful" });
    }
    ModelState.AddModelError("username", $"Username {model.UserName} is taken");
    return BadRequest(ModelState);
}

Step 6: Test

Test the api by signing up and then logging in using POSTMAN.