Setup basic code for login.

API/Controllers/AccountController.cs

@@ -0,0 +1,82 @@
+using System.Security.Cryptography;
+using System.Text;
+using System.Threading.Tasks;
+using API.Data;
+using API.DTOs;
+using API.Entities;
+using API.Interfaces;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+
+namespace API.Controllers
+{
+    public class AccountController : BaseApiController
+    {
+        private readonly DataContext _context;
+        private readonly ITokenService _tokenService;
+        private readonly ILogger<AccountController> _logger;
+
+        public AccountController(DataContext context, ITokenService tokenService, ILogger<AccountController> logger)
+        {
+            _context = context;
+            _tokenService = tokenService;
+            _logger = logger;
+        }
+
+        [HttpPost("register")]
+        public async Task<ActionResult<UserDto>> Register(RegisterDto registerDto)
+        {
+            _logger.LogInformation("Username: " + registerDto.Password);
+            if (await UserExists(registerDto.Username))
+            {
+                return BadRequest("Username is taken.");
+            }
+            
+            using var hmac = new HMACSHA512();
+            var user = new AppUser
+            {
+                UserName = registerDto.Username.ToLower(),
+                PasswordHash = hmac.ComputeHash(Encoding.UTF8.GetBytes(registerDto.Password)),
+                PasswordSalt = hmac.Key
+            };
+
+            _context.Users.Add(user);
+            await _context.SaveChangesAsync();
+
+            return new UserDto()
+            {
+                Username = user.UserName,
+                Token = _tokenService.CreateToken(user)
+            };
+        }
+
+        [HttpPost("login")]
+        public async Task<ActionResult<UserDto>> Login(LoginDto loginDto)
+        {
+            var user = await _context.Users.SingleOrDefaultAsync(x => x.UserName == loginDto.Username.ToLower());
+
+            if (user == null) return Unauthorized("Invalid username");
+            
+            using var hmac = new HMACSHA512(user.PasswordSalt);
+
+            var computedHash = hmac.ComputeHash(Encoding.UTF8.GetBytes(loginDto.Password));
+
+            for (int i = 0; i < computedHash.Length; i++)
+            {
+                if (computedHash[i] != user.PasswordHash[i]) return Unauthorized("Invalid password");
+            }
+
+            return new UserDto()
+            {
+                Username = user.UserName,
+                Token = _tokenService.CreateToken(user)
+            };
+        }
+        
+        private async Task<bool> UserExists(string username)
+        {
+            return await _context.Users.AnyAsync(user => user.UserName == username.ToLower());
+        }
+    }
+}

API/Controllers/BaseApiController.cs

@@ -0,0 +1,13 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace API.Controllers
+{
+    [ApiController]
+    [Route("api/[controller]")]
+    public class BaseApiController : ControllerBase
+    {
+        public BaseApiController()
+        {
+        }
+    }
+}

API/DTOs/LoginDto.cs

@@ -0,0 +1,8 @@
+namespace API.DTOs
+{
+    public class LoginDto
+    {
+        public string Username { get; set; }
+        public string Password { get; set; }
+    }
+}

API/DTOs/RegisterDto.cs

@@ -0,0 +1,13 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace API.DTOs
+{
+    public class RegisterDto
+    {
+        [Required]
+        public string Username { get; set; }
+        [Required]
+        [StringLength(8, MinimumLength = 4)]
+        public string Password { get; set; }
+    }
+}

API/DTOs/UserDto.cs

@@ -0,0 +1,8 @@
+namespace API.DTOs
+{
+    public class UserDto
+    {
+        public string Username { get; set; }
+        public string Token { get; set; }
+    }
+}

API/Data/DataContext.cs

@@ -0,0 +1,15 @@
+using API.Entities;
+using Microsoft.EntityFrameworkCore;
+
+namespace API.Data
+{
+    public class DataContext : DbContext
+    {
+        public DataContext(DbContextOptions options) : base(options)
+        {
+            
+        }
+        
+        public DbSet<AppUser> Users { get; set; }
+    }
+}

API/Entities/AppUser.cs

@@ -0,0 +1,28 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using API.Entities.Interfaces;
+
+
+namespace API.Entities
+{
+    public class AppUser : IHasConcurrencyToken
+    {
+        public int Id { get; set; }
+        public string UserName { get; set; }
+        public byte[] PasswordHash { get; set; }
+        public byte[] PasswordSalt { get; set; }
+        public DateTime Created { get; set; } = DateTime.Now;
+        public DateTime LastActive { get; set; }
+
+        [ConcurrencyCheck]
+        public uint RowVersion { get; set; }
+
+        public void OnSavingChanges()
+        {
+            RowVersion++;
+        }
+        
+        
+        
+    }
+}

API/Entities/Interfaces/IHasConcurrencyToken.cs

@@ -0,0 +1,19 @@
+namespace API.Entities.Interfaces
+{
+    /// <summary>
+    /// An interface abstracting an entity that has a concurrency token.
+    /// </summary>
+    public interface IHasConcurrencyToken
+    {
+        /// <summary>
+        /// Gets the version of this row. Acts as a concurrency token.
+        /// </summary>
+        uint RowVersion { get; }
+
+        /// <summary>
+        /// Called when saving changes to this entity.
+        /// </summary>
+        void OnSavingChanges();
+
+    }
+}

API/Errors/ApiException.cs

@@ -0,0 +1,16 @@
+namespace API.Errors
+{
+    public class ApiException
+    {
+        public int Status { get; set; }
+        public string Message { get; set; }
+        public string Details { get; set; }
+
+        public ApiException(int status, string message = null, string details = null)
+        {
+            Status = status;
+            Message = message;
+            Details = details;
+        }
+    }
+}

API/Extensions/ApplicationServiceExtensions.cs

@@ -0,0 +1,23 @@
+using API.Data;
+using API.Interfaces;
+using API.Services;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace API.Extensions
+{
+    public static class ApplicationServiceExtensions
+    {
+        public static IServiceCollection AddApplicationServices(this IServiceCollection services, IConfiguration config)
+        {
+            services.AddScoped<ITokenService, TokenService>();
+            services.AddDbContext<DataContext>(options =>
+            {
+                options.UseSqlite(config.GetConnectionString("DefaultConnection"));
+            });
+
+            return services;
+        }
+    }
+}

API/Extensions/IdentityServiceExtensions.cs

@@ -0,0 +1,28 @@
+using System.Collections;
+using System.Text;
+using Microsoft.AspNetCore.Authentication.JwtBearer;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.IdentityModel.Tokens;
+
+namespace API.Extensions
+{
+    public static class IdentityServiceExtensions
+    {
+        public static IServiceCollection AddIdentityServices(this IServiceCollection services, IConfiguration config)
+        {
+            services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
+                .AddJwtBearer(options =>
+                {
+                    options.TokenValidationParameters = new TokenValidationParameters()
+                    {
+                        ValidateIssuerSigningKey = true,
+                        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(config["TokenKey"])),
+                        ValidateIssuer = false,
+                        ValidateAudience = false
+                    };
+                });
+            return services;
+        }
+    }
+}

API/Interfaces/ITokenService.cs

@@ -0,0 +1,9 @@
+using API.Entities;
+
+namespace API.Interfaces
+{
+    public interface ITokenService
+    {
+        string CreateToken(AppUser user);
+    }
+}

API/Middleware/ExceptionMiddleware.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Net;
+using System.Text.Json;
+using System.Threading.Tasks;
+using API.Errors;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace API.Middleware
+{
+    public class ExceptionMiddleware
+    {
+        private readonly RequestDelegate _next;
+        private readonly ILogger<ExceptionMiddleware> _logger;
+        private readonly IHostEnvironment _env;
+
+        public ExceptionMiddleware(RequestDelegate next, ILogger<ExceptionMiddleware> logger, IHostEnvironment env)
+        {
+            _next = next;
+            _logger = logger;
+            _env = env;
+        }
+
+        public async Task InvokeAsync(HttpContext context)
+        {
+            _logger.LogError("The middleware called");
+            try
+            {
+                await _next(context); // downstream middlewares or http call
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, ex.Message);
+                context.Response.ContentType = "application/json";
+                context.Response.StatusCode = (int) HttpStatusCode.InternalServerError;
+                
+                var response = _env.IsDevelopment() 
+                    ? new ApiException(context.Response.StatusCode, ex.Message, ex.StackTrace?.ToString())
+                    : new ApiException(context.Response.StatusCode, "Internal Server Error");
+                
+                var options = new JsonSerializerOptions
+                {
+                    PropertyNamingPolicy = 
+                        JsonNamingPolicy.CamelCase
+                };
+
+                var json = JsonSerializer.Serialize(response, options);
+
+                await context.Response.WriteAsync(json);
+
+            }
+        }
+    }
+}

API/Services/TokenService.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+using API.Entities;
+using API.Interfaces;
+using Microsoft.Extensions.Configuration;
+using Microsoft.IdentityModel.Tokens;
+using JwtRegisteredClaimNames = Microsoft.IdentityModel.JsonWebTokens.JwtRegisteredClaimNames;
+
+
+namespace API.Services
+{
+    public class TokenService : ITokenService
+    {
+        private readonly SymmetricSecurityKey _key;
+
+        public TokenService(IConfiguration config)
+        {
+            _key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(config["TokenKey"]));
+        }
+
+        public string CreateToken(AppUser user)
+        {
+            var claims = new List<Claim>
+            {
+                new Claim(JwtRegisteredClaimNames.NameId, user.UserName)
+            };
+            
+            var creds = new SigningCredentials(_key, SecurityAlgorithms.HmacSha512Signature);
+
+            var tokenDescriptor = new SecurityTokenDescriptor()
+            {
+                Subject = new ClaimsIdentity(claims),
+                Expires = DateTime.Now.AddDays(7),
+                SigningCredentials = creds
+            };
+            
+            var tokenHandler = new JwtSecurityTokenHandler();
+            var token = tokenHandler.CreateToken(tokenDescriptor);
+
+            return tokenHandler.WriteToken(token);
+        }
+    }
+}

API/Startup.cs

@@ -2,6 +2,8 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using API.Extensions;
+using API.Middleware;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.HttpsPolicy;
@@ -16,18 +18,21 @@ namespace API
 {
     public class Startup
     {
-        public Startup(IConfiguration configuration)
-        {
-            Configuration = configuration;
-        }
+        private readonly IConfiguration _config;
 
-        public IConfiguration Configuration { get; }
+        public Startup(IConfiguration config)
+        {
+            _config = config;
+        }
 
         // This method gets called by the runtime. Use this method to add services to the container.
         public void ConfigureServices(IServiceCollection services)
         {
 
+            services.AddApplicationServices(_config);
             services.AddControllers();
+            services.AddCors();
+            services.AddIdentityServices(_config);
             services.AddSwaggerGen(c =>
             {
                 c.SwaggerDoc("v1", new OpenApiInfo { Title = "API", Version = "v1" });
@@ -37,9 +42,11 @@ namespace API
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
         public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
         {
+            app.UseMiddleware<ExceptionMiddleware>();
+            
             if (env.IsDevelopment())
             {
-                app.UseDeveloperExceptionPage();
+                //app.UseDeveloperExceptionPage();
                 app.UseSwagger();
                 app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "API v1"));
             }
@@ -47,6 +54,11 @@ namespace API
             app.UseHttpsRedirection();
 
             app.UseRouting();
+            
+            // Ordering is important. Cors, authentication, authorization
+            app.UseCors(policy => policy.AllowAnyHeader().AllowAnyMethod().WithOrigins("https://localhost:4200"));
+            
+            app.UseAuthentication();
 
             app.UseAuthorization();