JObject.ToObject 与模型状态错误

Question

在一个 ASP.NET 核心项目中，我已从使用 ResourceModel 切换到使用 JObject 作为我的 [FromBody] 参数。然后，我将JObject.ToObject<ResourceModel>() 传递给服务，但希望为ContainsKey 和类似功能维护JObject 本身。

如果JObject.ToObject<T> 成功，我可以使用TryValidateModel()，如果失败，就简单地返回BadRequest(ModelState)。但是，我遇到的问题是JObject.ToObject<T> 引发异常时 - 我不确定如何捕获ModelState 中的序列化错误。

例子：

public class Person {
    public string FirstName {get;set;}
    public string LastName {get;set;}
    public uint Age {get;set;}
}
public class CommonParameters {
    [FromQuery] public string? Fields {get;set;}
    public string UserName {get;set;}
    public IPAddress? RequestorIp {get;set;}
    public JObject? JsonBody {get;set;}
}
public class PersonController : ControllerBase {
    private readonly PersonService _personService;
    // this is how I had been doing it
    [HttpPatch("obsolete/{id}")] // this method doesn't actually exist, but is shown for the example
    public async Task<IActionResult> UpdatePerson([FromRoute] int id, [FromBody] Person parameters, [FromHeader] CommonParameters commonParameters) {
         SetCommonParameters(commonParameters, parameters);
         // if parameters.Age in the json body was a string, BadRequest is returned before this method even starts
         _personService.Set(parameters);
         await _personService.SaveChangesAsync();
         return NoContent();
    }
    // this is how I'm trying to do it now, so that I only update Age if JObject.ContainsKey("Age")
    // instead of parameters.Age != default, etc.
    [HttpPatch("{id}")]
    public async Task<IActionResult> UpdatePerson([FromRoute] int Id, [FromBody] JObject parameters, [FromHeader] CommonParameters commonParameters) {
         SetCommonParameters(commonParameters, parameters);
         // if parameters.Age is a string in this version, a JsonReaderException 
         // or JsonSerializationException is thrown when I call JObject.ToObject<>()
         // and I have to validate the model separately after that
         // what this means is, a BadRequest with the ModelState errors is not
         // returned if there's an issue with the json.
         var model = parameters.ToObject<Person>();
         if (!TryValidateModel(model)) return BadRequest(ModelState);
         _personService.Set(person);
         await _personService.SaveChangesAsync();
         return NoContent();
    }
    private void SetCommonParameters(CommonParameters commonParameters, JObject? jsonBody = null) {
        commonParameters.JsonBody = jsonBody;
        commonParameters.UserName = User.Identity?.Name;
        commonParameters.RequestorIp = Request.HttpContext.Connection.RemoteIpAddress;
    }
}

---

编辑：正如 Guru Stron 所要求的，这是一个无效模型/json 对象的示例。

型号：

public class ContactInfo {
  // PhoneNumber being a struct representing an 11-digit phone number
  // PhoneType being an enum of Cell, Work, Home, etc.
  public Dictionary<PhoneType, PhoneNumber[]> PhoneNumbers {get;set;} = new();
  public string? Apartment {get;set;}
  public int AddressNumber {get;set;}
  public string StreetName {get;set;}
  public string City {get;set;}
  // State being an enum of the 50 United States of America
  public State State {get;set;}
}

无效的json

{
  "phoneNumbers": {
    "work": [ "1-111-111-1111" ],
    "home": [ "2-222-222-2222" ],
    "cell": [ "1-800-CALL-NOW" ]
  },
  "apartment": null,
  "addressNumber": "3a",
  "streetName": "Imagination St.",
  "city": "Atlantis",
  "state": "Atlantic"
}

在这种情况下，将ContactInfo 的上述json 传递给请求ContactInfo 参数的控制器方法将返回一个错误请求，指示状态无效，地址编号无效，和 电话号码无效 - 没有专门对此进行测试，如下所示。

{
  "errors": {
    "phoneNumbers": [
      "Could not parse phone number \"1-800-CALL-NOW\". The value must be an 11-digit numeric value."
    ],
    "addressNumber": [
      "The value could not be parsed as int."
    ],
    "state": [
      "\"Atlantic\" is an invalid value for State. The following values are valid: ..."
    ]
  }
}

如果控制器请求JObject，然后我调用JObject.ToObject 并捕获异常，我将得到一个这些错误 - 例如Could not parse phone number "1-800-CALL-NOW". The value must be an 11-digit numeric value. 其他错误将被忽略直到那个问题被修复并且用户再次尝试。

Answer 1

我终于想通了...我需要做的就是向JObject.ToObject<> 提供一个JsonSerializer，并包含一个错误处理程序，将错误标记为已处理。例如：

var serializer = new JsonSerializer();
serializer.Error += (sender, args) =>
{
    if (args.ErrorContext.Error is JsonException)
    {
        ModelState.AddModelError(args.ErrorContext.Path, args.ErrorContext.Error.Message);
        args.ErrorContext.Handled = true;
    }
};

var value = parameters.ToObject<Person>(serializer);
if (!TryValidateModel(value)) return ValidationProblem(ModelState);

据我了解，默认的Microsoft.AspNetCore.Mvc.Formatters.NewtonsoftJsonInputFormater 执行类似的错误处理；我仍然不确定如何直接使用该处理程序，但我在这里所拥有的东西可以满足我的需要。