WCF Rest 服务错误处理和 WebChannelFactory

Question

根据我的理解，以下内容应该从 WCF Rest 服务正确抛出自定义错误:

[DataContract(Namespace = "")]
public class ErrorHandler
{
    [DataMember]
    public int errorCode { get; set; }

    [DataMember]
    public string errorMessage { get; set; }
} // End of ErrorHandler

public class Implementation : ISomeInterface
{
    public string SomeMethod()
    {
        throw new WebFaultException<ErrorHandler>(new ErrorHandler()
        {
            errorCode = 5,
            errorMessage = "Something failed"
        }, System.Net.HttpStatusCode.BadRequest);
    }
}

在 Fiddler 这似乎有效，我得到以下原始数据:

HTTP/1.1 400 Bad Request
Cache-Control: private
Content-Length: 145
Content-Type: application/xml; charset=utf-8
Server: Microsoft-IIS/7.5
X-AspNet-Version: 4.0.30319
Set-Cookie: ASP.NET_SessionId=gwsy212sbjfxdfzslgyrmli1; path=/; HttpOnly
X-Powered-By: ASP.NET
Date: Thu, 03 May 2012 17:49:14 GMT

<ErrorHandler xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><errorCode>5</errorCode><errorMessage>Something failed</errorMessage></ErrorHandler>

但现在在我的客户端我有以下代码:

WebChannelFactory<ISomeInterface> client = new WebChannelFactory<ISomeInterface>(new Uri(targetHost));

ISomeInterface someInterface = client.CreateChannel();
try
{
  var result = someInterface.SomeMethod();
}
catch(Exception ex)
{
   // Try to examine the ErrorHandler to get additional details.
}

现在，当代码运行时，它命中了一个 System.ServiceModel.ProtocolException消息“远程服务器返回意外响应:(400) 错误请求。”。看来此时我还没有办法看到ErrorHandler的详细信息。有没有人遇到过这个？有没有办法在这一点上获得 ErrorHander 的详细信息？

Answer 1

WebChannelFactory或 ChannelFactory只会向您披露通用的 CommunicationException .您将需要使用 IClientMessageInspector行为或依赖 WebRequest返回实际错误。

对于 IClientMessageInspector方法 - 参见 this blog entry 中的评论.

对于 WebRequest方法，你可以通过以下方式来捕捉WebException .

try { }
catch (Exception ex)
{
    if (ex.GetType().IsAssignableFrom(typeof(WebException)))
    {
        WebException webEx = ex as WebException;
        if (webEx.Status == WebExceptionStatus.ProtocolError)
        {
            using (StreamReader exResponseReader = new StreamReader(webEx.Response.GetResponseStream()))
            {
                string exceptionMessage = exResponseReader.ReadToEnd();
                Trace.TraceInformation("Internal Error: {0}", exceptionMessage);
            }
        }
    }
}