我需要在 ASP.Net 核心的验证属性中返回自定义验证结果（响应） Web API

Question

我需要在 ASP.Net core 中返回自定义的验证结果（响应）失效属性 Web API 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 object 以便我可以返回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;
    }
}

但它不起作用我需要返回我自己的错误响应

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

我期待的回应：

 { "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：

1. 创建包含返回字段的自定义 ValidationError model：

    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(); } }

2. 创建自定义 IActionResult。 默认显示验证错误时，会返回BadRequestObjectResult，HTTP状态码为400。这里我们可以更改Http状态码。

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

3. 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); } } }

4. 在 Startup.ConfigureServices 中将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; }; });

5. 在操作方法或 controller 添加自定义操作过滤器。

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

6. 使用自定义属性验证创建学生 model（Min18Years）：

    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."); } }

运行应用程序后，结果如下：

参考：

处理 ASP.NET 核心 web API 中的验证失败错误

处理 ASP.NET 核心的验证响应 Web API