C# MVC框架如何實現用戶認證

在C# MVC框架中實現用戶認證通常涉及以下幾個步驟：

1. 創建用戶模型（User Model）： 首先，你需要創建一個用戶模型來表示用戶數據。這個模型通常包含用戶名、密碼哈希、電子郵件等信息。

   public class User
   {
       public int Id { get; set; }
       public string Username { get; set; }
       public string PasswordHash { get; set; }
       public string Email { get; set; }
   }
   

2. 創建用戶上下文（User Context）： 使用Entity Framework或其他ORM工具創建一個用戶上下文來管理用戶數據。

   public class UserContext : DbContext
   {
       public DbSet<User> Users { get; set; }
   
       protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
       {
           optionsBuilder.UseSqlServer("YourConnectionStringHere");
       }
   }
   

3. 創建用戶存儲（User Repository）： 創建一個用戶存儲類來封裝對用戶數據的訪問。

   public class UserRepository : IUserRepository
   {
       private readonly UserContext _context;
   
       public UserRepository(UserContext context)
       {
           _context = context;
       }
   
       public IEnumerable<User> GetAllUsers()
       {
           return _context.Users.ToList();
       }
   
       public User GetUserById(int id)
       {
           return _context.Users.Find(id);
       }
   
       public bool AddUser(User user)
       {
           _context.Users.Add(user);
           _context.SaveChanges();
           return true;
       }
   
       public bool UpdateUser(User user)
       {
           _context.Users.Update(user);
           _context.SaveChanges();
           return true;
       }
   
       public bool DeleteUser(int id)
       {
           var user = _context.Users.Find(id);
           if (user == null) return false;
   
           _context.Users.Remove(user);
           _context.SaveChanges();
           return true;
       }
   }
   

4. 創建用戶認證服務（Authentication Service）： 創建一個用戶認證服務來處理用戶注冊、登錄和注銷等操作。

   public class AuthenticationService
   {
       private readonly IUserRepository _userRepository;
       private readonly IConfiguration _configuration;
   
       public AuthenticationService(IUserRepository userRepository, IConfiguration configuration)
       {
           _userRepository = userRepository;
           _configuration = configuration;
       }
   
       public bool RegisterUser(string username, string password, string email)
       {
           var hashedPassword = HashPassword(password);
           var user = new User { Username = username, PasswordHash = hashedPassword, Email = email };
           return _userRepository.AddUser(user);
       }
   
       public bool LoginUser(string username, string password)
       {
           var user = _userRepository.GetUserById(username);
           if (user == null || !VerifyPassword(password, user.PasswordHash)) return false;
   
           // Generate and store authentication token
           var token = GenerateJwtToken(user);
           // Store the token in the user's session or cookie
           return true;
       }
   
       public void LogoutUser(string username)
       {
           // Invalidate the user's authentication token
       }
   
       private string HashPassword(string password)
       {
           // Use a hashing algorithm like BCrypt
           return BCrypt.Net.BCrypt.HashPassword(password);
       }
   
       private bool VerifyPassword(string password, string hashedPassword)
       {
           // Use a hashing algorithm like BCrypt
           return BCrypt.Net.BCrypt.Verify(password, hashedPassword);
       }
   
       private string GenerateJwtToken(User user)
       {
           // Generate a JWT token using the user's information
           var claims = new[]
           {
               new Claim(ClaimTypes.Name, user.Username),
               new Claim(ClaimTypes.Email, user.Email)
           };
   
           var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_configuration["JwtSecret"]));
           var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256);
   
           var token = new JwtSecurityToken(
               issuer: _configuration["JwtIssuer"],
               audience: _configuration["JwtAudience"],
               claims: claims,
               expires: DateTime.UtcNow.AddMinutes(30),
               signingCredentials: creds
           );
   
           return new JwtSecurityTokenHandler().WriteToken(token);
       }
   }
   

5. 創建控制器（Controller）： 創建一個控制器來處理用戶認證相關的請求。

   [ApiController]
   [Route("api/[controller]")]
   public class AuthenticationController : ControllerBase
   {
       private readonly IAuthenticationService _authenticationService;
       private readonly IConfiguration _configuration;
   
       public AuthenticationController(IAuthenticationService authenticationService, IConfiguration configuration)
       {
           _authenticationService = authenticationService;
           _configuration = configuration;
       }
   
       [HttpPost("register")]
       public IActionResult Register([FromBody] RegisterModel model)
       {
           if (_authenticationService.RegisterUser(model.Username, model.Password, model.Email))
           {
               return Ok();
           }
           return BadRequest();
       }
   
       [HttpPost("login")]
       public IActionResult Login([FromBody] LoginModel model)
       {
           if (_authenticationService.LoginUser(model.Username, model.Password))
           {
               return Ok(new { token = _authenticationService.GenerateJwtToken(new User { Username = model.Username }) });
           }
           return Unauthorized();
       }
   }
   

6. 創建模型（Model）： 創建模型來表示注冊和登錄請求的數據。

   public class RegisterModel
   {
       public string Username { get; set; }
       public string Password { get; set; }
       public string Email { get; set; }
   }
   
   public class LoginModel
   {
       public string Username { get; set; }
       public string Password { get; set; }
   }
   

7. 配置依賴注入（Dependency Injection）： 在Startup.cs中配置依賴注入，將用戶認證服務和其他相關服務注入到控制器中。

   public void ConfigureServices(IServiceCollection services)
   {
       services.AddDbContext<UserContext>(options =>
           options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
   
       services.AddScoped<IUserRepository, UserRepository>();
       services.AddScoped<IAuthenticationService, AuthenticationService>();
       services.AddControllers();
   }
   
   public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
   {
       if (env.IsDevelopment())
       {
           app.UseDeveloperExceptionPage();
       }
   
       app.UseRouting();
   
       app.UseEndpoints(endpoints =>
       {
           endpoints.MapControllers();
       });
   }
   

通過以上步驟，你可以在C# MVC框架中實現基本的用戶認證功能。這只是一個簡單的示例，實際應用中可能需要更多的安全措施和功能，如密碼重置、電子郵件驗證、會話管理等。