如何反序列化 422 无法处理的实体错误模型并将错误绑定到 asp.net core razor pages 模型状态

Question

我的Asp.Net Core 3.1 API返回422 Unprocessable Entity错误响应如下图：

{
  "type": "https://test.com/modelvalidationproblem",
  "title": "One or more model validation errors occurred.",
  "status": 422,
  "detail": "See the errors property for details.",
  "instance": "/api/path",
  "traceId": "8000003f-0001-ec00-b63f-84710c7967bb",
  "errors": {
    "FirstName": [
      "The FirstName field is required."
    ]
  }
}

如何反序列化此响应并将错误添加到Asp.Net Core 3.1 Razor Pages 中的模型验证错误？

我尝试创建如下所示的模型，

错误模型：

public class UnprocessableEntity
{
    public string Type { get; set; }
    public string Title { get; set; }
    public int Status { get; set; }
    public string Detail { get; set; }
    public string Instance { get; set; }
    public string TraceId { get; set; }
    public Errors Errors { get; set; }
}

public class Errors
{
    ....// what should I need to add here? Keys and messages will be dynamic
}

但是我应该在Errors 类中添加什么？错误键和消息将是动态的。

一旦知道了以上内容，我就可以在我的 razor 页面中添加模型状态错误，如下所示，

using var responseStream = await response.Content.ReadAsStreamAsync();
var errorResponse = await JsonSerializer.DeserializeAsync<UnprocessableEntity>(responseStream);

foreach (var error in errorResponse.errors)
{
    ModelState.AddModelError(error.key, error.Message[0]); // I'm stuck here
}

Answer 1

我已经修改了@Yongqing Yu 的答案并使其通用。

422 错误模型：

public class UnprocessableEntity<T>
{
    [JsonPropertyName("type")]
    public string Type { get; set; }

    [JsonPropertyName("title")]
    public string Title { get; set; }

    [JsonPropertyName("status")]
    public int Status { get; set; }

    [JsonPropertyName("detail")]
    public string Detail { get; set; }

    [JsonPropertyName("instance")]
    public string Instance { get; set; }

    [JsonPropertyName("traceId")]
    public string TraceId { get; set; }

    [JsonPropertyName("errors")]
    public T Errors { get; set; }
}

型号：

public class EventRegisterViewModel
{
    [Required]
    [MaxLength(200)]
    [RegularExpression(ValidationConstants.ALPHABETSWITHSPACE, ErrorMessage = "Enter only alphabets")]
    [Display(Name = "First Name")]
    public string FirstName { get; set; }

    [Required]
    [MaxLength(200)]
    [RegularExpression(ValidationConstants.ALPHABETSWITHSPACE, ErrorMessage = "Enter only alphabets")]
    [Display(Name = "Last Name")]
    public string LastName { get; set; }

    [MinLength(10, ErrorMessage = "Please Enter 10 digit Mobile Number")]
    [MaxLength(10)]
    [RegularExpression(ValidationConstants.NUMBERSONLY, ErrorMessage = "Invalid Mobile Number")]
    [Display(Name = "Mobile Number")]
    public string MobileNumber { get; set; }

    [Required]
    [MaxLength(200)]
    [EmailAddress]
    [Display(Name = "Email Address")]
    public string EmailAddress { get; set; }
}

错误模型：

public class EventRegistrationValidationErrors
{
    public IEnumerable<string> FirstName { get; set; }
    public IEnumerable<string> LastName { get; set; }
    public IEnumerable<string> MobileNumber { get; set; }
    public IEnumerable<string> EmailAddress { get; set; }
}

在反序列化时，

using var responseStream = await response.Content.ReadAsStreamAsync().ConfigureAwait(false);
var errorResponse = await JsonSerializer.DeserializeAsync<UnprocessableEntity<EventRegistrationValidationErrors>>(responseStream).ConfigureAwait(false);
var errorFieldNames = typeof(EventRegistrationValidationErrors)
                        .GetProperties()
                        .Select(field => field.Name)
                        .ToList();

foreach (var errorField in errorFieldNames)
{
    var errorLists = (List<string>)errorResponse.errors
                        .GetType()
                        .GetProperty(errorField)
                        .GetValue(errorResponse.errors);

    if (!(errorLists is null))
    {
        ModelState.AddModelError($"Event.{errorField}", errorLists[0]);
    }
}

希望这对那里的人有所帮助。

Answer 2

首先，您应该确保关键字段名称与从 api(pay attention to case) 返回的 json 相同。

 public class UnprocessableEntity
{
    public string type { get; set; }
    public string tTitle { get; set; }
    public int status { get; set; }
    public string detail { get; set; }
    public string instance { get; set; }
    public string traceId { get; set; }
    public Errors errors { get; set; }
}

那么Errors类的字段应该包含验证类的所有字段，并且字段名称要一致，但是需要define their type as an array to receive，因为json中errors返回的每个字段都是一个数组. （这里我创建了一个名为StudInfo 的简单验证类）：

    public class StudInfo
    {
        [Key]
        public int Id { get; set; }
        [Required]
        public string Name { get; set; }
    }


    public class Errors
    {
        public List<string> Id { get; set; }
        public List<string> Name { get; set; }
    }

然后你可以使用如下代码：

       using var responseStream = await response.Content.ReadAsStreamAsync();
       var errorResponse = await JsonSerializer.DeserializeAsync<UnprocessableEntity>(responseStream);
        var t = typeof(Errors);
        var fieldNames = typeof(Errors).GetProperties()
                        .Select(field => field.Name)
                        .ToList();
        foreach (var name in fieldNames)
        {
            List<string> errorLists = (List<string>)errorResponse.errors.GetType().GetProperty(name).GetValue(errorResponse.errors);
            if (errorLists != null)
            {
                ModelState.AddModelError(name, errorLists[0]); 
            }

        }