前言

一个在实际应用中 EF Core 集成 FluentValidation 进行数据校验的例子。

Step By Step 步骤

1. 创建一个 Asp.Net Core WebApi 项目

2. 引用以下 Nuget 包

   FluentValidation.AspNetCore
   Microsoft.AspNetCore.Identity.EntityFrameworkCore
   Microsoft.EntityFrameworkCore.Relational
   Microsoft.EntityFrameworkCore.SqlServer
   Microsoft.EntityFrameworkCore.Tools

3. 创建 Login 操作方法的请求参数模型类 LoginRequest

   // LoginRequest 类只是一个普通的C#类，
   // 没有标注任何的Attribute或者实现任何的接口，
   // 它的唯一责任就是传递数据
   public record LoginRequest(string Email, string Password, string PasswordConfirm);
   

4. 修改 appsettings.json，添加数据库连接字符串

   {"Logging": {"LogLevel": {"Default": "Information","Microsoft.AspNetCore": "Warning"}},"AllowedHosts": "*","ConnectionStrings": {"Default": "Server=(localdb)\\mssqllocaldb;Database=IdentityTestDB;Trusted_Connection=True;MultipleActiveResultSets=true"}
   }	
   

5. 创建用户实体类User和Role

   using Microsoft.AspNetCore.Identity;public class User : IdentityUser<long>
   {public DateTime CreationTime { get; set; }public string? NickName { get; set; }
   }public class Role : IdentityRole<long>
   {}
   

6. 创建继承自IdentityDbContext的上下文类

   using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
   using Microsoft.EntityFrameworkCore;public class TestDbContext : IdentityDbContext<User, Role, long>
   {public TestDbContext(DbContextOptions<TestDbContext> options): base(options){}protected override void OnModelCreating(ModelBuilder modelBuilder){base.OnModelCreating(modelBuilder);modelBuilder.ApplyConfigurationsFromAssembly(this.GetType().Assembly);}
   }
   

7. 打开 Program.cs，注册 Identity 和 FluentValidation

   using FluentValidation;
   using FluentValidation.AspNetCore;
   using Microsoft.AspNetCore.Identity;
   using Microsoft.EntityFrameworkCore;
   using System.Reflection;var builder = WebApplication.CreateBuilder(args);// Add services to the container.builder.Services.AddControllers();
   // Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
   builder.Services.AddEndpointsApiExplorer();
   builder.Services.AddSwaggerGen();// 注册标识框架相关的服务，并配置相关选项
   IServiceCollection services = builder.Services;
   services.AddDbContext<TestDbContext>(opt =>
   {string connStr = builder.Configuration.GetConnectionString("Default")!;opt.UseSqlServer(connStr);
   });
   services.AddDataProtection();
   services.AddIdentityCore<User>(options =>
   {options.Password.RequireDigit = false;options.Password.RequireLowercase = false;options.Password.RequireNonAlphanumeric = false;options.Password.RequireUppercase = false;options.Password.RequiredLength = 6;options.Tokens.PasswordResetTokenProvider = TokenOptions.DefaultEmailProvider;options.Tokens.EmailConfirmationTokenProvider = TokenOptions.DefaultEmailProvider;
   });
   var idBuilder = new IdentityBuilder(typeof(User), typeof(Role), services);
   idBuilder.AddEntityFrameworkStores<TestDbContext>().AddDefaultTokenProviders().AddRoleManager<RoleManager<Role>>().AddUserManager<UserManager<User>>();// 注册 FluentValidation 服务
   Assembly assembly = Assembly.GetExecutingAssembly();
   builder.Services.AddFluentValidationAutoValidation().AddFluentValidationClientsideAdapters().AddValidatorsFromAssembly(assembly);var app = builder.Build();// Configure the HTTP request pipeline.
   if (app.Environment.IsDevelopment())
   {app.UseSwagger();app.UseSwaggerUI();
   }app.UseHttpsRedirection();app.UseAuthorization();app.MapControllers();app.Run();	
   

8. 编写请求参数模型类 LoginRequest

   public record LoginRequest(string UserName, string Password);
   

9. 编写继承自AbstractValidator的数据校验类，留意注释

   using FluentValidation;
   using Microsoft.EntityFrameworkCore;public class LoginRequestValidator : AbstractValidator<LoginRequest>
   {// 通过构造方法注入了TestDbContextpublic LoginRequestValidator(TestDbContext dbCtx){RuleFor(x => x.UserName).NotNull()// 使用TestDbContext服务检查用户名是否存在// 同步方式.Must(name => dbCtx.Users.Any(u => u.UserName == name))// 异步方式，但使用异步后出错，暂时未能找到解决方案//.MustAsync((name,_) => dbCtx.Users.AnyAsync(u => u.UserName == name))// 用Lambda表达式的形式使用模型类中的属性对报错信息进行格式化.WithMessage(c => $"用户名{c.UserName}不存在");}
   }
   

10. 打开登录请求控制器，编写 Login API

    using Microsoft.AspNetCore.Mvc;namespace FluentValidationSample2.Controllers
    {[ApiController][Route("[controller]/[action]")]public class TestController : ControllerBase{[HttpPost]public ActionResult Login(LoginRequest req){return Ok();}}
    }
    

11. 在 Postman 或 Swagger 测试 Login API，如果请求的用户名不存在，即会返回代码中定义的错误信息