前言
上一篇已经介绍了identity在web api中的基本配置，本篇来完成用户的注册，登录，获取jwt token。
开始
开始之前先配置一下jwt相关服务。
配置JWT
首先NuGet安装包：
<PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="5.0.10" />appsettings.json中添加jwt配置：
"JwtSettings": {"SecurityKey": "qP1yR9qH2xS0vW2lA3gI4nF0zA7fA3hB","ExpiresIn": "00:10:00"
}为了方便，新建一个配置类JwtSettings：
public class JwtSettings
{public string SecurityKey { get; set; }public TimeSpan ExpiresIn { get; set; }
}在Startup中配置jwt：
public void ConfigureServices(IServiceCollection services)
{//省略......var jwtSettings = Configuration.GetSection(nameof(JwtSettings)).Get<JwtSettings>();services.AddSingleton(jwtSettings);var tokenValidationParameters = new TokenValidationParameters{ValidateIssuer = false,ValidateAudience = false,ValidateIssuerSigningKey = true,IssuerSigningKey = new SymmetricSecurityKey(Encoding.ASCII.GetBytes(jwtSettings.SecurityKey)),ClockSkew = TimeSpan.Zero,};services.AddAuthentication(options =>{options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;options.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;}).AddJwtBearer(options => { options.TokenValidationParameters = tokenValidationParameters; });
}最后别忘了UseAuthentication：
app.UseAuthentication(); // add
app.UseAuthorization();结构搭建
下面把项目基本结构搭建好，做好接口，后面实现：
以下是各个类的定义：
// 用户注册请求参数
public class RegisterRequest
{public string UserName { get; set; }public string Password { get; set; }public string Address { get; set; }
}// 用户登录请求参数
public class LoginRequest
{public string UserName { get; set; }public string Password { get; set; }
}// 注册 登录 成功后返回 token
public class TokenResponse
{[JsonPropertyName("access_token")] public string AccessToken { get; set; }[JsonPropertyName("token_type")] public string TokenType { get; set; }
}// 登录 注册 失败时返回错误信息
public class FailedResponse
{public IEnumerable<string> Errors { get; set; }
}// IUserService 接口
public interface IUserService
{Task<TokenResult> RegisterAsync(string username, string password, string address);Task<TokenResult> LoginAsync(string username, string password);
}// UserService 实现
public class UserService : IUserService
{public Task<TokenResult> RegisterAsync(string username, string password, string address){throw new System.NotImplementedException();}public Task<TokenResult> LoginAsync(string username, string password){throw new System.NotImplementedException();}
}// TokenResult 定义
public class TokenResult
{public bool Success => Errors == null || !Errors.Any();public IEnumerable<string> Errors { get; set; }public string AccessToken { get; set; }public string TokenType { get; set; }
}最后是UserController：
[Route("api/[controller]")]
[ApiController]
public class UserController : ControllerBase
{private readonly IUserService _userService;public UserController(IUserService userService){_userService = userService;}[HttpPost("Register")]public async Task<IActionResult> Register(RegisterRequest request){var result = await _userService.RegisterAsync(request.UserName, request.Password, request.Address);if (!result.Success){return BadRequest(new FailedResponse(){Errors = result.Errors});}return Ok(new TokenResponse{AccessToken = result.AccessToken,TokenType = result.TokenType});}[HttpPost("Login")]public async Task<IActionResult> Login(LoginRequest request){var result = await _userService.LoginAsync(request.UserName, request.Password);if (!result.Success){return Unauthorized(new FailedResponse(){Errors = result.Errors});}return Ok(new TokenResponse{AccessToken = result.AccessToken,TokenType = result.TokenType});}
}service实现
上面已经做好了基本的结构，接下来就是实现UserService中的RegisterAsync和LoginAsync方法了。这里主要用到identity中的UserManager，UserManager封装了很多用户操作的现成方法。
在UserService中先做一个私有方法，根据user创建jwt token；用户注册，登录成功后调用此方法得到token返回即可：
private TokenResult GenerateJwtToken(AppUser user)
{var key = Encoding.ASCII.GetBytes(_jwtSettings.SecurityKey);var tokenDescriptor = new SecurityTokenDescriptor{Subject = new ClaimsIdentity(new[]{new Claim(JwtRegisteredClaimNames.Jti, Guid.NewGuid().ToString("N")),new Claim(JwtRegisteredClaimNames.Sub, user.Id.ToString())}),IssuedAt = DateTime.UtcNow,NotBefore = DateTime.UtcNow,Expires = DateTime.UtcNow.Add(_jwtSettings.ExpiresIn),SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(key),SecurityAlgorithms.HmacSha256Signature)};var jwtTokenHandler = new JwtSecurityTokenHandler();var securityToken = jwtTokenHandler.CreateToken(tokenDescriptor);var token = jwtTokenHandler.WriteToken(securityToken);return new TokenResult(){AccessToken = token,TokenType = "Bearer"};
}注册方法实现：
public async Task<TokenResult> RegisterAsync(string username, string password, string address)
{var existingUser = await _userManager.FindByNameAsync(username);if (existingUser != null){return new TokenResult(){Errors = new[] {"user already exists!"}, //用户已存在};}var newUser = new AppUser() {UserName = username, Address = address};var isCreated = await _userManager.CreateAsync(newUser, password);if (!isCreated.Succeeded){return new TokenResult(){Errors = isCreated.Errors.Select(p => p.Description)};}return GenerateJwtToken(newUser);
}登录方法实现：
public async Task<TokenResult> LoginAsync(string username, string password)
{var existingUser = await _userManager.FindByNameAsync(username);if (existingUser == null){return new TokenResult(){Errors = new[] {"user does not exist!"}, //用户不存在};}var isCorrect = await _userManager.CheckPasswordAsync(existingUser, password);if (!isCorrect){return new TokenResult(){Errors = new[] {"wrong user name or password!"}, //用户名或密码错误};}return GenerateJwtToken(existingUser);
}最后，别忘了注册UserService：
services.AddScoped<IUserService, UserService>();swagger配置
为了方便测试，可以配置一下swagger
NuGet安装包：
<PackageReference Include="Swashbuckle.AspNetCore" Version="5.6.3" />ConfigureServices：
services.AddSwaggerGen(c =>
{c.SwaggerDoc("v1", new OpenApiInfo{Title = "Sample.Api",Version = "v1",Description = "Sample.Api Swagger Doc"});c.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme{Description = "Input the JWT like: Bearer {your token}",Name = "Authorization",In = ParameterLocation.Header,Type = SecuritySchemeType.ApiKey,BearerFormat = "JWT",Scheme = "Bearer"});c.AddSecurityRequirement(new OpenApiSecurityRequirement{{new OpenApiSecurityScheme{Reference = new OpenApiReference{Type = ReferenceType.SecurityScheme,Id = "Bearer"}},Array.Empty<string>()}});
});app.UseSwagger();
app.UseSwaggerUI(c => c.SwaggerEndpoint("/swagger/v1/swagger.json", "Sample.Api v1"));测试一下
随便输入abc进行注册，返回了一些密码规则的错误：
这个规则在注册identity服务时可以配置：
services.AddIdentityCore<AppUser>(options =>
{options.Password.RequireDigit = true;options.Password.RequireLowercase = false;options.Password.RequireUppercase = false;options.Password.RequireNonAlphanumeric = false;
}).AddEntityFrameworkStores<AppDbContext>();identityOptions还支持一些其他配置。
下面注册成功后返回了token：
使用刚刚注册的账号测试登录，也没有问题：
最后
本篇完成了identity的登录，注册，获取token，下一篇将介绍如何使用refresh token。
参考：
ASP.NET Core 简介 Identity | Microsoft Docs[1]
Mohamad Lawand - DEV Community[2]
参考资料
[1]
ASP.NET Core 简介 Identity | Microsoft Docs: https://docs.microsoft.com/zh-cn/aspnet/core/security/authentication/identity?view=aspnetcore-5.0&tabs=visual-studio
[2]Mohamad Lawand - DEV Community: https://dev.to/moe23/comments
