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TestDbContext
   	public 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