ASPNetCoreBlazorLearningWBS/AspNetCoreApi/Services/JWTAuthenticationService.cs

using AspNetCoreApi.Models;
using Microsoft.AspNetCore.Identity;
using Microsoft.IdentityModel.Tokens;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;

namespace AspNetCoreApi.Services
{
    public class JWTAuthenticationService
    {
        private readonly UserManager<ApplicationUser> _userManager;
        private readonly string _key = "ThisIsMyMyJWTKey1234!ThisIsMyMyJWTKey1234!";


        public JWTAuthenticationService(UserManager<ApplicationUser> userManager)
        {
            _userManager = userManager;
        }

        public async Task<string> Authenticate(string username, string password)
        {
            var user = await _userManager.FindByNameAsync(username);
            if (user == null)
                return null;

            if (await _userManager.CheckPasswordAsync(user, password) == false)
                return null;

            var tokenHandler = new JwtSecurityTokenHandler();
            var key = Encoding.UTF8.GetBytes(_key);
            var tokenDescriptor = new SecurityTokenDescriptor
            {
                Subject = new ClaimsIdentity(new Claim[]
                {
                    new Claim(ClaimTypes.Name, user.UserName),
                    new Claim(ClaimTypes.NameIdentifier, user.Id)
                }),
                Expires = DateTime.UtcNow.AddHours(0.5),
                SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(key), SecurityAlgorithms.HmacSha256Signature)
            };

            var token = tokenHandler.CreateToken(tokenDescriptor);
            return tokenHandler.WriteToken(token);

        }
    }
}