(转载)NetCore3 WebApi使用模型验证参数合法性

后端 › c#
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在接口开发过程中免不了要去验证参数的合法性，模型验证就是帮助我们去验证参数的合法性。我们可以在需要验证的model属性上加上Data Annotations特性后就会自动帮我们在action前去验证输入数据的合法性。

1、定义一个class

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1     public class TokenRequest
2     {
3         [Required]
4         [StringLength(6)]
5         public string Username { get; set; }
6 
7         [Required]
8         public string Password { get; set; }
9     }

2、在Controller接口中，使用ModelState.IsValid验证

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if (!ModelState.IsValid)
{
      return BadRequest();
}

.NetCore WebApi对于参数验证默认返回样式。

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{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "|2cf913f6-46e1cc8505a94470.",
  "errors": {
    "Password": ["The Password field is required."],
    "Username": ["The Username field is required."]
  }
}

3、如果想统一验证，而不是到处都是ModelState.IsValid

(1)定义Attribute继承ActionFilterAttribute，重写OnActionExecuting方法

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 1     public class ValidateModelAttribute : ActionFilterAttribute
 2     {
 3         public override void OnActionExecuting(ActionExecutingContext context)
 4         {
 5             var modelState = context.ModelState;
 6             if (!modelState.IsValid)
 7             {
 8                 var validationErrors = modelState.Keys
 9                     .SelectMany(key => modelState[key].Errors.Select(x => new ValidationError(key, x.ErrorMessage)));
10                 context.Result = new ObjectResult(validationErrors);
11             }
12         }
13     }
14 
15     public class ValidationError
16     {
17         public string Field { get; set; }
18 
19         public string Message { get; set; }
20 
21         public ValidationError(string field, string message)
22         {
23             Field = field;
24             Message = message;
25         }
26     }

(2)Starup类ConfigureServices

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 1             services.AddControllers(options =>
 2             {
 3                 // 添加自定义验证方式
 4                 options.Filters.Add<ValidateModelAttribute>();
 5             });
 6 
 7             services.Configure<ApiBehaviorOptions>(options =>
 8             {
 9                 // 关闭默认的验证方式
10                 options.SuppressModelStateInvalidFilter = true;
11             });

这样就可以全局验证参数，而不是在Controller的Action中到处都是ModelState

验证效果

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1 [{
2   "field": "Password",
3   "message": "The Password field is required."
4 }, {
5   "field": "Username",
6   "message": "The field Username must be a string with a maximum length of 6."
7 }]

转自博客园