內置數(shù)據(jù)校驗機制

• 框架內置了對數(shù)據(jù)校驗的支持

- 在System.ComponentModel.DataAnnotations這個命名空間下:
	- 比如[Required]、[EmailAddress] 、[RegularExpression] 、 CustomValidationAttribute、IValidatableObject等待

• demo演示

// LoginRequest1.cs

using System.ComponentModel.DataAnnotations;

namespace WebApplicationAboutDataValidate
{
    public class LoginRequest1
    {
        [Required]
        [EmailAddress]
        [RegularExpression("^.*@(qq|163)\\.com$", ErrorMessage = "只支持QQ和163郵箱")]
        public string Email { get; set; }

        [Required]
        [StringLength(10, MinimumLength = 3)]
        public string Password { get; set; }
        [Compare(nameof(Password2), ErrorMessage = "兩次密碼必須一致")]
        public string Password2 { get; set; }
    }
}

• 測試效果

- 提交如下字段

{
  "email": "user@example.com",
  "password": "string",
  "password2": "string"
}

- 返回:

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "00-840f868ea1c247a51f659d0092a68ae9-a7f61df6b9a99cd3-00",
  "errors": {
    "Email": [
      "只支持QQ和163郵箱"
    ]
  }
}

- 提交如下字段:

{
  "email": "user@qq.com",
  "password": "string123",
  "password2": "string"
}

- 返回:

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "00-e635ad8de5684008becbe67b9be814e8-fea276f49eca5228-00",
  "errors": {
    "Password2": [
      "兩次密碼必須一致"
    ]
  }
}

• 內置數(shù)據(jù)校驗機制的問題點

- 校驗規(guī)則都是和模型類耦合在一起，違反“單一職責原則”；
- 很多常用的校驗都需要編寫自定義校驗規(guī)則，而且寫起來麻煩。

數(shù)據(jù)校驗機制第三方庫--- FluentValidation1

• FluentValidation在很多項目中都可以使用(比如WinForm,WPF)

• 注意事項: FluentValidation可以和內置的數(shù)據(jù)校驗機制混用,但最好不要這么干,避免混淆和未知的坑.

• 安裝庫

- Install-Package Microsoft.EntityFrameworkCore.Tools -Version 6.0.0
-  Install-Package FluentValidation.AspNetCore -Version 10.3.4 // 這里不要搞成6的版本,有坑

• Program.cs注冊一下

// LoginRequest1.cs
using System.ComponentModel.DataAnnotations;

namespace WebApplicationAboutDataValidate
{
    public class LoginRequest1
    {
       
        public string Email { get; set; }
        public string UserName { get; set; }
        public string Password { get; set; }
        public string Password2 { get; set; }
    }
}


// AddNewUserRequestValidator.cs---自定義校驗器

using FluentValidation;

namespace WebApplicationAboutDataValidate
{
    public class AddNewUserRequestValidator : AbstractValidator<LoginRequest1>
    {
        public AddNewUserRequestValidator()
        {
            RuleFor(x => x.Email).NotNull().EmailAddress().WithMessage("郵箱必須是合法地址").Must(x => x.EndsWith("@163.com") || x.EndsWith("@qq.com")).WithMessage("支持163或者QQ郵箱");
            RuleFor(x => x.UserName).NotNull().Length(3,10);
            RuleFor(x => x.Password).Equal(x => x.Password2).WithMessage("兩次密碼必須一致");
        }
    }
}

// Program.cs
......
builder.Services.AddSwaggerGen();
// 注冊全局驗證器
builder.Services.AddFluentValidation(fv => {
    Assembly assembly = Assembly.GetExecutingAssembly();
    fv.RegisterValidatorsFromAssembly(assembly);
});
var app = builder.Build();
......


// 測試接口

using Microsoft.AspNetCore.Mvc;

namespace WebApplicationAboutDataValidate.Controllers
{
    [ApiController]
    [Route("[controller]/[action]")]
    public class ValidateDataController : ControllerBase
    {

        [HttpPost]
        public ActionResult Login(LoginRequest1 req)
        {
            return Ok(req);
        }
    }
}

- 測試: https://localhost:7263/ValidateData/Login

{
  "email": "string",
  "userName": "string",
  "password": "string",
  "password2": "string111"
}

- 返回結果

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "00-7666f45f49e7afcab428d6bbd34d5bfb-1d6ed200ab8f73e3-00",
  "errors": {
    "Email": [
      "郵箱必須是合法地址",
      "支持163或者QQ郵箱"
    ],
    "Password": [
      "兩次密碼必須一致"
    ]
  }
}

• FluentValidation + DI高級功能---依賴注入: 可以通過構造方法來向校驗器注入服務

using FluentValidation;
using Microsoft.AspNetCore.Identity;

namespace WebApplicationAboutDataValidate
{
    public class AddNewUserRequestValidator : AbstractValidator<LoginRequest1>
    {
        public AddNewUserRequestValidator(UserManager<LoginRequest1> userManager)
        {
            RuleFor(x => x.Email).NotNull().EmailAddress().WithMessage("郵箱必須是合法地址").Must(x => x.EndsWith("@163.com") || x.EndsWith("@qq.com")).WithMessage("支持163或者QQ郵箱");
            RuleFor(x => x.UserName).NotNull().Length(3,10).MustAsync(async (x,_) => await userManager.FindByNameAsync(x) == null).WithMessage("用戶名已存在");
            //RuleFor(x => x.Password).Equal(x => x.Password2).WithMessage("兩次密碼必須一致");
            RuleFor(x => x.Password).Equal(x => x.Password2).WithMessage(x => $"密碼{x.Password}和{x.Password2}不一致");
        }
    }
}

核心要點總結

1. 分離關注點：FluentValidation 將校驗邏輯從模型類中分離出來
2. 鏈式編程：使用流暢的接口設計，代碼可讀性更強
3. 靈活性強：支持復雜的業(yè)務邏輯校驗，包括異步校驗
4. 錯誤信息定制：可以靈活定制錯誤消息，支持動態(tài)消息
5. 依賴注入支持：可以在校驗器中注入服務，實現(xiàn)更復雜的業(yè)務校驗