hn-dotnet/Apps/Api/Controllers/AccountsController.cs

using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Threading.Tasks;
using Api.Models;
using HN.Infrastructure.Identity;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.IdentityModel.Tokens;

namespace Api.Controllers
{
  [ApiController]
  [Route("api/[controller]")]
  public sealed class AccountsController : ControllerBase
  {
    private readonly UserManager<User> _usersManager;
    private readonly SignInManager<User> _signinManager;
    private readonly TokenValidationParameters _tokenParameters;

    public AccountsController(UserManager<User> usersManager, SignInManager<User> signinManager, TokenValidationParameters tokenParameters)
    {
      _usersManager = usersManager;
      _signinManager = signinManager;
      _tokenParameters = tokenParameters;
    }

    [HttpPost("login")]
    [AllowAnonymous]
    public async Task<IActionResult> Login(LoginViewModel command)
    {
      var user = await _usersManager.FindByNameAsync(command.Username);

      if (user == null)
      {
        return NotFound();
      }

      var result = await _signinManager.CheckPasswordSignInAsync(user, command.Password, false);

      if (!result.Succeeded)
      {
        return BadRequest();
      }

      var tokenDescriptor = new SecurityTokenDescriptor
      {
        Subject = new ClaimsIdentity(new Claim[]
        {
          new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
          new Claim(ClaimTypes.Name, command.Username),
        }),

        Expires = DateTime.UtcNow.AddDays(7),
        Issuer = _tokenParameters.ValidIssuer,
        Audience = _tokenParameters.ValidAudience,
        SigningCredentials = new SigningCredentials(_tokenParameters.IssuerSigningKey, SecurityAlgorithms.HmacSha256Signature)
      };

      return Ok(new JwtSecurityTokenHandler().CreateEncodedJwt(tokenDescriptor));
    }
  }
}