asp.net – 从启用AJAX的WCF服务返回错误详细信息

简短版本：在 AJAX启用的WCF服务中抛出异常(除了打开门并发回所有异常详细信息之外),是否有/有什么建议的方式将错误详细信息返回给客户端？

长版本：

我有一个相对简单的启用AJAX的WCF服务,我使用默认服务代理从客户端调用.我在下面提供了代码片段,但我不相信代码本身有什么问题.

我的问题是,如果我在服务中抛出异常,返回给客户端的错误对象总是通用的：

{
    "ExceptionDetail":null,"ExceptionType":null,"Message":"The server was unable to process the request..."
    "StackTrace":null
}

理想情况下,我想在客户端上显示不同的错误消息,具体取决于出错.

一个选择是允许在WCF故障中的异常,这将为我提供完整的堆栈跟踪和一切,但我感谢安全性的关注,这实际上比我需要更多的信息.我可以做的只是能够发回一个描述问题或某事的字符串,但我没有看到一种方法来做到这一点.

我的服务代码：

[ServiceContract(Namespace = "MyNamespace")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class MyService
{
    [OperationContract]
    public void DoStuff(string param1,string etc)
    {
        //Do some stuff that maybe causes an exception
    }
}

在客户端上

MyNamespace.MyService.DoStuff(
    param1,etc,function() { alert("success"); },HandleError);

其中“HandleError”只是一个通用错误处理方法,将显示有关错误的详细信息.

解决方法

快速但非优先的方式.

<serviceDebug includeExceptionDetailInFaults="true"/>

在您的服务行为将给您所需的所有细节.

好的方式

应用程序的所有异常都将转换为JsonError并使用DataContractJsonSerializer进行序列化. Exception.Message直接使用. FaultExceptions提供了FaultCode,其他异常处理为未知的faultcode -1.

使用HTTP状态代码400发送FaultException,其他异常是HTTP代码500 – 内部服务器错误.这不是必需的,因为faultcode可以用来决定是否和未知的错误.这在我的应用程序是方便的

错误处理程序

internal class CustomErrorHandler : IErrorHandler
{
    public bool HandleError(Exception error)
    {
        //Tell the system that we handle all errors here.
        return true;
    }

    public void ProvideFault(Exception error,System.ServiceModel.Channels.MessageVersion version,ref System.ServiceModel.Channels.Message fault)
    {
        if (error is FaultException<int>)
        {
            FaultException<int> fe = (FaultException<int>)error;

            //Detail for the returned value
            int faultCode = fe.Detail;
            string cause = fe.Message;

            //The json serializable object
            JsonError msErrObject = new JsonError { Message = cause,FaultCode = faultCode };

            //The fault to be returned
            fault = Message.CreateMessage(version,"",msErrObject,new DataContractJsonSerializer(msErrObject.GetType()));

            // tell WCF to use JSON encoding rather than default XML
            WebBodyFormatMessageProperty wbf = new WebBodyFormatMessageProperty(WebContentFormat.Json);

            // Add the formatter to the fault
            fault.Properties.Add(WebBodyFormatMessageProperty.Name,wbf);

            //Modify response
            HttpResponseMessageProperty rmp = new HttpResponseMessageProperty();

            // return custom error code,400.
            rmp.StatusCode = System.Net.HttpStatusCode.BadRequest;
            rmp.StatusDescription = "Bad request";

            //Mark the jsonerror and json content
            rmp.Headers[HttpResponseHeader.ContentType] = "application/json";
            rmp.Headers["jsonerror"] = "true";

            //Add to fault
            fault.Properties.Add(HttpResponseMessageProperty.Name,rmp);
        }
        else
        {
            //Arbitraty error
            JsonError msErrObject = new JsonError { Message = error.Message,FaultCode = -1};

            // create a fault message containing our FaultContract object
            fault = Message.CreateMessage(version,new DataContractJsonSerializer(msErrObject.GetType()));

            // tell WCF to use JSON encoding rather than default XML
            var wbf = new WebBodyFormatMessageProperty(WebContentFormat.Json);
            fault.Properties.Add(WebBodyFormatMessageProperty.Name,wbf);

            //Modify response
            var rmp = new HttpResponseMessageProperty();

            rmp.Headers[HttpResponseHeader.ContentType] = "application/json";
            rmp.Headers["jsonerror"] = "true";

            //Internal server error with exception mesasage as status.
            rmp.StatusCode = System.Net.HttpStatusCode.InternalServerError;
            rmp.StatusDescription = error.Message;

            fault.Properties.Add(HttpResponseMessageProperty.Name,rmp);
        }
    }

    #endregion
}

Webbehaviour用于安装上述错误处理程序

internal class AddErrorHandlerBehavior : WebHttpBehavior
{
    protected override void AddServerErrorHandlers(ServiceEndpoint endpoint,EndpointDispatcher endpointDispatcher)
    {
        base.AddServerErrorHandlers(endpoint,endpointDispatcher);

        //Remove all other error handlers
        endpointDispatcher.ChannelDispatcher.ErrorHandlers.Clear();
        //Add our own
        endpointDispatcher.ChannelDispatcher.ErrorHandlers.Add(new CustomErrorHandler());
    }
}

json错误数据合同

指定json错误格式.
在此添加属性以更改错误格式.

[DataContractFormat]
public class JsonError
{
    [DataMember]
    public string Message { get; set; }

    [DataMember]
    public int FaultCode { get; set; }
}

使用错误处理程序

自托管

ServiceHost wsHost = new ServiceHost(new Webservice1(),new Uri("http://localhost/json")); 

ServiceEndpoint wsEndpoint = wsHost.AddServiceEndpoint(typeof(IWebservice1),new WebHttpBinding(),string.Empty);

wsEndpoint.Behaviors.Add(new AddErrorHandlerBehavior());

App.config中

<extensions>  
  <behaviorExtensions>  
    <add name="errorHandler"  
        type="WcfServiceLibrary1.ErrorHandlerElement,WcfServiceLibrary1" />  
  </behaviorExtensions>  
</extensions>

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