通过ajax执行发布时，返回错误请求，而不是JSON结果

Question

jqXHR = $.ajax({ url: $frm.attr("action"), type: "POST", dataType: "json", cache: false,
  headers: headers, contentType: "application/json;charset=UTF-8", data: ko.mapping.toJSON(data, map),
  beforeSend: function(x) {
    if (x && x.overrideMimeType) {
      return x.overrideMimeType("application/json;charset=UTF-8");
    }
  }
});

jqXHR.fail(function(xhr, err, msg) {  /* xhr.responseText  NEED TO BE JSON!!! */ });

在Chrome中

标头

Request Method:POST
Status Code:400 Bad Request
Request Headersview source
Accept:application/json, text/javascript, */*; q=0.01
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8,pt-BR;q=0.6,pt;q=0.4
Connection:keep-alive
Content-Length:10
Content-Type:application/json;charset=UTF-8
User-Agent:Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.117 Safari/537.36
X-Requested-With:XMLHttpRequest
Request Payloadview source {Id:0}
Response Headersview source
Cache-Control:private
Content-Length:54
Content-Type:application/json; charset=utf-8
Date:Thu, 27 Feb 2014 14:01:59 GMT
Server:Microsoft-IIS/8.0
X-AspNet-Version:4.0.30319
X-AspNetMvc-Version:5.1
X-Powered-By:ASP.NET

响应

[{“ Name”：“ Nome”，“ ErrorMessage”：“ campoobrigatório。”}]

适用于Chrome！

在IE8中

标头（请求）

POST /Motivos/Salvar HTTP/1.1
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: pt-br
x-requested-with: XMLHttpRequest
Content-Type: application/json;charset=UTF-8
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0)
Content-Length: 10
Connection: Keep-Alive
Pragma: no-cache

标头（响应）

HTTP/1.1 400 Bad Request
Cache-Control: private
Content-Type: text/html
Server: Microsoft-IIS/8.0
X-AspNetMvc-Version: 5.1
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Thu, 27 Feb 2014 13:51:46 GMT
Content-Length: 11

Bad Request

不行！！

Asp.net MVC

过滤

public class HandleExceptionAttribute : HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        if (filterContext.HttpContext.Request.IsAjaxRequest() && filterContext.Exception != null)
        {
            filterContext.HttpContext.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
            var ex = filterContext.Exception.GetBaseException();
            filterContext.Result = new JsonResult
            {
                JsonRequestBehavior = JsonRequestBehavior.AllowGet,
                Data = new
                {
                    ex.Message,
                    ex.GetType().Name
                }
            };
            filterContext.ExceptionHandled = true;
        }
        else
        {
            base.OnException(filterContext);
        }
    }
}

应用于GlobalFilterCollection

控制者

[ValidateJsonAntiForgeryToken, HttpPost]
public virtual JsonResult Salvar(TViewModel viewModel)
{
    if (ModelState.IsValid)
    {
        TEntity model;
        if (default(TKey).Equals(viewModel.Id))
        {
            model = Mapper.Map<TEntity>(viewModel);
            AdicionarEntidade(model, viewModel);
        }
        else
        {
            model = Repositorio.Get(viewModel.Id);
            Mapper.Map(viewModel, model, typeof(TViewModel), typeof(TEntity));
            SalvarEntidade(model, viewModel);
        }

        return SalvarResult(model);
    }

    Response.StatusCode = 400;
    return Json(ModelState.ToJson(), JsonRequestBehavior.AllowGet);
}

延伸性

public static object ToJson(this ModelStateDictionary dic, params string[] othersMessages)
{
    var states = (from e in dic where e.Value.Errors.Count > 0
                  select new { Name = e.Key, e.Value.Errors[0].ErrorMessage }).ToList();

    if (othersMessages != null)
        foreach (var message in othersMessages)
            states.Add(new { Name = "", ErrorMessage = message });

    return states;
}

问题

• 为什么没有xhr.resposeText对象？
• 如何以与在Chrome中恢复相同的方式检索JSON？

我需要JSON来填充表单！

注意：03/11/2014

当我添加Response.TrySkipIisCustomErrors = true;控制器时，它就可以工作了！responseText返回json。为什么？

Answer 1

认为这是IIS尝试使用自定义错误响应而不是发送控制器正在生成的错误消息的问题。

<system.webServer>
    ...
    <httpErrors existingResponse="PassThrough"></httpErrors>
    ...
</system.webServer>

要么

Response.TrySkipIisCustomErrors = true;

参考-https:
//stackoverflow.com/a/4029197/1304559

查看此博客文章http://weblog.west-wind.com/posts/2009/Apr/29/IIS-7-Error-Pages-
taking-over-500-Errors

由于响应代码设置为400，因此IIS将其内容替换为其自定义错误页面内容