如何本地化Json反序列化的异常消息？请求接口时传递了无效参数？

Question

我的开发环境是.Net7 WebApi（开箱即用）

下面是相关代码。 DataAnnotations 我已经实现了本地化。

using System.ComponentModel.DataAnnotations;

namespace WebApi.Dtos
{
    public class UserRegistrationDto
    {
        [Required(ErrorMessage = "UserNameRequiredError")]
        [MinLength(6, ErrorMessage = "UserNameMinLengthError")]
        [MaxLength(30, ErrorMessage = "UserNameMaxLengthError")]
        public required string UserName { get; set; }

        [Required(ErrorMessage = "PasswordRequiredError")]
        public required string Password { get; set; }
    }
}

[HttpPost]
public async Task<IActionResult> RegisterUser([FromBody] UserRegistrationDto userRegistration)
{
    return Ok(1);
    // IdentityResult userResult = await _userManager.CreateAsync(new IdentityUser { UserName = userRegistration.UserName }, userRegistration.Password);

    // return userResult.Succeeded ? StatusCode(201) : BadRequest(userResult);
}

当请求正文为无效 JSON 时。

curl -X 'POST' \
  'https://localhost:7177/Authenticate/RegisterUser' \
  -H 'accept: */*' \
  -H 'Api-Version: 1.0' \
  -H 'Content-Type: application/json' \
  -d '{}'

{
    "$": [
        "JSON deserialization for type 'WebApi.Dtos.UserRegistrationDto' was missing required properties, including the following: userName, password"
    ],
    "userRegistration": [
        "The userRegistration field is required."
    ]
}

当请求正文为空时。

curl -X 'POST' \
  'https://localhost:7177/Authenticate/RegisterUser' \
  -H 'accept: */*' \
  -H 'Api-Version: 1.0' \
  -H 'Content-Type: application/json' \
  -d ''

{
    "": [
        "The userRegistration field is required."
    ]
}

绑定DTO之前抛出异常信息，这个异常信息可以本地化吗？如果没有的话，是否可以捕获这些信息进行二次处理，比如返回固定的JSON格式？

我在Program.cs入口文件中尝试过这个，但并不理想。

.ConfigureApiBehaviorOptions(options =>
{
    options.SuppressModelStateInvalidFilter = false;
    options.InvalidModelStateResponseFactory = context =>
    {
        bool knownExceptions = context.ModelState.Values.SelectMany(x => x.Errors).Where(x => x.Exception is JsonException || (x.Exception is null && String.IsNullOrWhiteSpace(x.ErrorMessage) == false)).Count() > 0;
        if (knownExceptions)
        {
            return new BadRequestObjectResult(new { state = false, message = localizer["InvalidParameterError"].Value });
        }
        // ...
        return new BadRequestObjectResult(context.ModelState);
    };
})

我也尝试过这个方法，但是无法捕获单独绑定DTO时失败的异常信息。它们会像上面的写法一样和ErrorMessage异常信息一起出现在DTO中。

.AddControllers(options =>
{
    // options.Filters.Add(...);
    // options.ModelBindingMessageProvider // This doesn't work either, it seems to support [FromForm]
})

回到主题，能本地化吗？或者代码有问题。我不久前刚刚学习.Net。我了解到的信息大部分来自搜索引擎和官方文档。预先感谢。

Answer 1

使用以下方法。

.AddControllers(options =>
{
    // options.ModelBindingMessageProvider.Set...
})

看来传递无效参数导致的JSON反序列化异常只能在客户端消除。到目前为止，我似乎还没有找到此异常的本地化，但目前对我来说并不是很重要。感谢@XinranShen 帮助我指明了正确的方向。

Answer 2

我也发现自己处于同样的位置，试图本地化 API 中的所有错误消息，所以我进行了更深入的挖掘。

“类型‘[Type]’的 JSON 反序列化缺少必需的属性，包括以下内容：[Properties]”消息是由反序列化期间在包 System.Text.Json 内引发的 JsonException 导致的 (ThrowHelper.Serialization) .ThrowJsonException_JsonRequiredPropertyMissing(..) ).

不幸的是，该消息的来源是硬编码的，无法更改。此外，使用此 ThrowHelper 方法（ReadStackFrame、ObjectDefaultConverter 等）的类/结构大多是内部的，无法使用依赖注入进行替换，因此无法影响此异常的创建（除了编写自己的 JSON 反序列化，即是）。

该异常最终在 Microsoft.AspNetCore.Mvc.Formatters.SystemTextJsonInputFormatter 的 ReadRequestBodyAsync 方法中进行处理，并将其添加到 ModelState 中。 ModelState 随后在 DefaultProblemDetailsFactory 中进行处理。

所以，你能做的最好的事情就是：

替换 ProblemDetailsFactory 并替换 ModelState 中的消息或
替换InputFormatter并用你自己的消息抛出另一个JsonException。

对于第一个变体，我们重建 DefaultProblemDetailsFactory 并将其添加到依赖项注入中：

自定义问题详细信息Factory.cs：

/// <inheritdoc />
public sealed class CustomProblemDetailsFactory : ProblemDetailsFactory
{
    private readonly ApiBehaviorOptions _options;
    private readonly Action<ProblemDetailsContext>? _configure;

    public CustomProblemDetailsFactory(
        IOptions<ApiBehaviorOptions> options,
        IOptions<ProblemDetailsOptions>? problemDetailsOptions = null)
    {
        _options = options?.Value ?? throw new ArgumentNullException(nameof(options));
        _configure = problemDetailsOptions?.Value?.CustomizeProblemDetails;
    }
    
    /// <inheritdoc />
    public override ProblemDetails CreateProblemDetails(
        HttpContext httpContext,
        int? statusCode = null,
        string? title = null,
        string? type = null,
        string? detail = null,
        string? instance = null)
    {
        statusCode ??= 500;

        var problemDetails = new ProblemDetails
        {
            Status = statusCode,
            Title = title,
            Type = type,
            Detail = detail,
            Instance = instance,
        };

        ApplyProblemDetailsDefaults(httpContext, problemDetails, statusCode.Value);

        return problemDetails;
    }

    /// <inheritdoc />
    public override ValidationProblemDetails CreateValidationProblemDetails(
        HttpContext httpContext,
        ModelStateDictionary modelStateDictionary,
        int? statusCode = null,
        string? title = null,
        string? type = null,
        string? detail = null,
        string? instance = null)
    {
        ArgumentNullException.ThrowIfNull(modelStateDictionary);

        statusCode ??= 400;

        if (modelStateDictionary.ContainsKey("$"))
        {
            modelStateDictionary.Remove("$");
            modelStateDictionary.TryAddModelError("$", "My error message");
        }

        var problemDetails = new ValidationProblemDetails(modelStateDictionary)
        {
            Title = Resources.ErrorMessages.ValidationProblemTitle,
            Status = statusCode,
            Type = type,
            Detail = detail,
            Instance = instance,
        };

        if (title != null)
        {
            problemDetails.Title = title;
        }

        ApplyProblemDetailsDefaults(httpContext, problemDetails, statusCode.Value);

        return problemDetails;
    }

    private void ApplyProblemDetailsDefaults(HttpContext httpContext, ProblemDetails problemDetails, int statusCode)
    {
        problemDetails.Status ??= statusCode;

        if (_options.ClientErrorMapping.TryGetValue(statusCode, out var clientErrorData))
        {
            problemDetails.Title ??= clientErrorData.Title;
            problemDetails.Type ??= clientErrorData.Link;
        }

        var traceId = Activity.Current?.Id ?? httpContext?.TraceIdentifier;
        if (traceId != null)
        {
            problemDetails.Extensions["traceId"] = traceId;
        }

        _configure?.Invoke(new() { HttpContext = httpContext!, ProblemDetails = problemDetails });
    }
}

在您的 Statup/Program.cs 中：

services.AddTransient<ProblemDetailsFactory, CustomProblemDetailsFactory>();
services.AddProblemDetails();

错误消息的替换发生在这些行中：

        if (modelStateDictionary.ContainsKey("$"))
        {
            modelStateDictionary.Remove("$");
            modelStateDictionary.TryAddModelError("$", "My error message");
        }

对于第 2 个变体

，我们可以将 SystemTextJsonInputFormatter 替换为我们自己的，并自行处理异常。

MyJsonInputFormatter.cs：

public class MyJsonInputFormatter : TextInputFormatter { private readonly SystemTextJsonInputFormatter _baseFormatter; public MyJsonInputFormatter(SystemTextJsonInputFormatter baseFormatter) { _baseFormatter = baseFormatter; foreach (var mediaType in _baseFormatter.SupportedMediaTypes) { SupportedMediaTypes.Add(mediaType); } foreach (var encoding in _baseFormatter.SupportedEncodings) { SupportedEncodings.Add(encoding); } } public override async Task<InputFormatterResult> ReadRequestBodyAsync(InputFormatterContext context, Encoding encoding) { ArgumentNullException.ThrowIfNull(context); ArgumentNullException.ThrowIfNull(encoding); var httpContext = context.HttpContext; var (inputStream, usesTranscodingStream) = GetInputStream(httpContext, encoding); try { await JsonSerializer.DeserializeAsync(inputStream, context.ModelType, _baseFormatter.SerializerOptions); } catch (JsonException jsonException) { var path = jsonException.Path ?? string.Empty; var modelStateException = WrapExceptionForModelState(jsonException); context.ModelState.TryAddModelError(path, modelStateException, context.Metadata); return InputFormatterResult.Failure(); } return await _baseFormatter.ReadRequestBodyAsync(context, encoding); } public override IReadOnlyList<string>? GetSupportedContentTypes(string contentType, Type objectType) { return _baseFormatter.GetSupportedContentTypes(contentType, objectType); } private Exception WrapExceptionForModelState(JsonException jsonException) { string message = "My error message"; return new InputFormatterException(message, jsonException); } private static (Stream inputStream, bool usesTranscodingStream) GetInputStream(HttpContext httpContext, Encoding encoding) { if (encoding.CodePage == Encoding.UTF8.CodePage) { return (httpContext.Request.Body, false); } var inputStream = Encoding.CreateTranscodingStream(httpContext.Request.Body, encoding, Encoding.UTF8, leaveOpen: true); return (inputStream, true); } }

在Startup/Program.cs中，我们搜索原来的SystemTextJsonInputFormatter并替换为我们自己的：

services.AddControllers(options => { int index; for (index = 0; index < options.InputFormatters.Count; index++) { if (options.InputFormatters[index] is SystemTextJsonInputFormatter) { break; } } if (index >= options.InputFormatters.Count) { throw new ArgumentException($"{nameof(SystemTextJsonInputFormatter)} not found"); } var originalFormatter = options.InputFormatters[index] as SystemTextJsonInputFormatter; options.InputFormatters[index] = new MyJsonInputFormatter(originalFormatter!); })

在这两种情况下，您都可以将错误消息替换为通用错误消息，但不幸的是，除了从原始错误消息中解析它们之外，无法检索原始参数（例如有问题的字段名称或错误原因） .

如何本地化Json反序列化的异常消息？请求接口时传递了无效参数？

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如何本地化Json反序列化的异常消息？请求接口时传递了无效参数？

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2个回答

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问题描述投票：0回答：2