我需要 return 在 ASP.Net 核心 Web API 的验证属性中自定义验证结果（响应）

Question

我需要 return 在 ASP.Net 核心 Web API 中自定义验证结果（响应）失效属性这是我创建的 ValidationAttribute。

class MaxResultsAttribute : ValidationAttribute
{
    protected override ValidationResult IsValid(object value, ValidationContext validationContext)
    {
        int maxResults = (int)value;

        if (maxResults <= 0)
        {
            return new CustomValidationResult(new ValidationResult("MaxResults should be greater than 0"));
        }

        return ValidationResult.Success;
    }
}

我创建了继承 ValidationResult 的 CustomValidationResult 对象，这样我就可以 return 我自己的自定义响应：

public class CustomValidationResult : ValidationResult
{
    public int FaultCode { get; set; }

    public string FaultMessage { get; set; }

    public CustomValidationResult(ValidationResult validationResult) : base(validationResult)
    {
        FaultCode = 123;
        FaultMessage = validationResult.ErrorMessage;
    }
}

但是没用我需要 return 我自己的错误响应

实际响应：

    {
      "MaxResults": [
        "MaxResults should be greater than 0"
      ] 
    }

我期待的回应：

    {
      "code": "55",
      "message": "The following validation errors occurred: MaxResults should be greater than 0"
    }

Answer 1

The response I'm expecting:

{
  "code": "55",
  "message": "The following validation errors occurred: MaxResults should be greater than 0"
}

我已经使用你的代码重现了这个问题，使用 CustomValidationResult，我只能得到像你这样的实际响应。要实现上述行为，作为解决方法，我建议您可以尝试使用操作过滤器来处理验证失败错误响应。检查以下示例代码：

创建包含 returned 字段的自定义 ValidationError 模型：

 public class ValidationError
 {
     [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
     public string Field { get; }

     [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
     public int Code { get; set; }

     public string Message { get; }

     public ValidationError(string field,int code, string message)
     {
         Field = field != string.Empty ? field : null;
         Code = code != 0 ? code : 55;
         Message = message;
     }
 }

 public class ValidationResultModel
 {
     public string Message { get; }

     public List<ValidationError> Errors { get; }

     public ValidationResultModel(ModelStateDictionary modelState)
     {
         Message = "Validation Failed";
         Errors = modelState.Keys
                 .SelectMany(key => modelState[key].Errors.Select(x => new ValidationError(key,0, x.ErrorMessage)))
                 .ToList();
     }
 }

创建自定义 IActionResult。默认情况下，当显示验证错误时，它会 return BadRequestObjectResult 并且 HTTP 状态代码为 400。这里我们可以更改 Http 状态代码。

 public class ValidationFailedResult : ObjectResult
 {
     public ValidationFailedResult(ModelStateDictionary modelState)
         : base(new ValidationResultModel(modelState))
     {
         StatusCode = StatusCodes.Status422UnprocessableEntity; //change the http status code to 422.
     }
 }

创建自定义操作过滤器属性：

 public class ValidateModelAttribute: ActionFilterAttribute
 { 
     public override void OnActionExecuting(ActionExecutingContext context)
     {
         if (!context.ModelState.IsValid)
         {
             context.Result = new ValidationFailedResult(context.ModelState);
         }
     }
 }

将Startup.ConfigureServices中的默认响应类型更改为SerializableError:

     services.AddControllers().ConfigureApiBehaviorOptions(options =>
     {
         options.InvalidModelStateResponseFactory = context =>
         {
             var result = new ValidationFailedResult(context.ModelState);

             // TODO: add `using System.Net.Mime;` to resolve MediaTypeNames
             result.ContentTypes.Add(MediaTypeNames.Application.Json);
             result.ContentTypes.Add(MediaTypeNames.Application.Xml);

             return result;
         };
     });

在动作方法或控制器中添加自定义动作过滤器。

 [HttpPost]
 [ValidateModel]
 public async Task<ActionResult<Student>> PostStudent(Student student)
 { 
    ...
 }

创建具有自定义属性验证的 Student 模型（18 岁以上）：

 public class Student
 {
     [Key]
     public int Id { get; set; }

     [Required(ErrorMessage = "Please enter name")]
     public string Name { get; set; }

     [Required(ErrorMessage = "Please choose admission date.")]
     [Display(Name = "Admission Date")]
     [DataType(DataType.Date)] 
     public DateTime AdmissionDate { get; set; }

     [Display(Name = "Date of Birth")]
     [DataType(DataType.Date)]
     [Min18Years]
     public DateTime DateofBirth { get; set; }
 }


 public class Min18Years : ValidationAttribute
 {
     protected override ValidationResult IsValid(object value, ValidationContext validationContext)
     {
         var student = (Student)validationContext.ObjectInstance;

         if (student.DateofBirth == null)
             return new ValidationResult("Date of Birth is required.");

         var age = DateTime.Today.Year - student.DateofBirth.Year;

         if (age <= 0)
         { 
             return new ValidationResult("MaxResults should be greater than 0");
         } 
         return (age >= 18)
             ? ValidationResult.Success
             : new ValidationResult("Student should be at least 18 years old.");
     }
 }

应用运行后，结果是这样的：

参考：

Handle Validation failure errors in ASP.NET Core web APIs

Handling validation responses for ASP.NET Core Web API

我需要 return 在 ASP.Net 核心 Web API 的验证属性中自定义验证结果（响应）

I need to return customized validation result (response) in validation attributes in ASP.Net core Web API

c#

asp.net

validationattribute

asp.net-web-api

asp.net-core