Question

我编写了一个.net 3.5控制台应用程序，用于从网页中获取一些数据。在我的Windows 7开发机器上进行调试和运行时，它运行正常。

但是当它在运行Debian 6.0.5和Mono 2.6.7的托管VPS上运行时，会在第二次或稍后调用UploadString()时抛出以下异常

System.Net.WebException: Error getting response stream (ReadDone2): ReceiveFailure ---> System.Exception:    at System.Net.WebConnection.HandleError(WebExceptionStatus st, System.Exception e, System.String where)
   at System.Net.WebConnection.ReadDone(IAsyncResult result)
   at System.Net.Sockets.Socket+SocketAsyncResult.Complete()
   at System.Net.Sockets.Socket+Worker.Receive()
  at System.Net.WebConnection.HandleError (WebExceptionStatus st, System.Exception e, System.String where) [0x00000] in <filename unknown>:0
  --- End of inner exception stack trace ---
  at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
  at System.Net.HttpWebRequest.GetResponse () [0x00000] in <filename unknown>:0
  at System.Net.WebClient.GetWebResponse (System.Net.WebRequest request) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.ReadAll (System.Net.WebRequest request, System.Object userToken) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadDataCore (System.Uri address, System.String method, System.Byte[] data, System.Object userToken) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadData (System.Uri address, System.String method, System.Byte[] data) [0x00000] in <filename unknown>:0

我的代码非常直接（我有一个try / catch / finally，一旦完成就处理了webclient）

client = new WebClient();
client.Proxy = null;
client.Credentials = new NetworkCredential("xxx", "xxx");
client.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
string postString = "";
foreach (KeyValuePair<string, string> pair in postData)
{
    postString += pair.Key + "=" + pair.Value + "&";
}
string content = client.UploadString(url, postString);
return content;

上面的代码包含在一个方法中，并且被多次调用以获取要提取的数据列表。第一次通话总是成功的。在第二次通话时，UploadString()将阻止30秒，然后是上述例外。通过观察控制台输出我注意到了这一点。如果我让它在循环中运行，经过几次尝试后它会成功，然后再次失败。

我有另一种方法，它有类似的代码，但是调用OpenRead()代替并返回内容。这在我的VPS上没有任何问题。另外，在VPS上托管了2个PHP5 Web应用程序，运行时没有任何问题。

由于我的VPS不支持X11，我不知道如何使用VS2010远程调试代码（或者我应该使用MonoDevelop）。我希望之前遇到过类似问题的人有一个答案，或者有一些指导来调试这个类似的设置。

有一个类似的问题，WebClient “error getting response stream，但答案没有帮助。感谢

编辑：我想到我可以在我的开发机器上运行MonoDevelop并进行调试。现在就这样做。

编辑：在Windows上尝试使用MonoDevelop + Mono 2.6.7进行调试会产生一系列问题，MySQL.Data无法连接到服务器，而WebClient会出现超时错误。

我使用HttpWebRequest，在VPS上运行但在我的机器上运行时遇到类似的异常

System.Net.WebException: Error getting response stream (ReadDone2): ReceiveFailure ---> System.Exception:    at System.Net.WebConnection.HandleError(WebExceptionStatus st, System.Exception e, System.String where)
   at System.Net.WebConnection.ReadDone(IAsyncResult result)
   at System.Net.Sockets.Socket+SocketAsyncResult.Complete()
   at System.Net.Sockets.Socket+Worker.Receive()
  at System.Net.WebConnection.HandleError (WebExceptionStatus st, System.Exception e, System.String where) [0x00000] in <filename unknown>:0
  --- End of inner exception stack trace ---
  at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
  at System.Net.HttpWebRequest.GetResponse () [0x00000] in <filename unknown>:0

HttpWebRequest实际上是在WebClient中使用的，因此获得相同的异常似乎是合理的。

编辑：能够编译Mono 2.10.8并运行它后，我得到了一个不同的例外。不确定它是否与Chunked transfer encoding有关，但在Windows中调试时再没有这样的错误。

System.Net.WebException: An error occurred performing a WebClient request. ---> System.Net.ProtocolViolationException: The number of bytes to be written is greater than the specified ContentLength.
  at System.Net.WebConnectionStream.CheckWriteOverflow (Int64 contentLength, Int64 totalWritten, Int64 size) [0x00000] in <filename unknown>:0
  at System.Net.WebConnectionStream.BeginWrite (System.Byte[] buffer, Int32 offset, Int32 size, System.AsyncCallback cb, System.Object state) [0x00000] in <filename unknown>:0
  at System.Net.WebConnectionStream.Write (System.Byte[] buffer, Int32 offset, Int32 size) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadDataCore (System.Uri address, System.String method, System.Byte[] data, System.Object userToken) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadData (System.Uri address, System.String method, System.Byte[] data) [0x00000] in <filename unknown>:0
  --- End of inner exception stack trace ---
  at System.Net.WebClient.UploadData (System.Uri address, System.String method, System.Byte[] data) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadData (System.Uri address, System.Byte[] data) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadData (System.String address, System.Byte[] data) [0x00000] in <filename unknown>:0
  at System.Net.WebClient.UploadString (System.String address, System.String data) [0x00000] in <filename unknown>:0
  at (wrapper remoting-invoke-with-check) System.Net.WebClient:UploadString (string,string)

编辑：如果我使用ProtocolViolationException，我会得到WebClient，但我得到ReceiveFailure，这与我之前使用HttpWebRequest时的异常相同，所有这些都在Mono上2.10.8

Answer 1

当你提到你正在使用Mono 2.6.7时，我停止阅读。这个版本已经有两年多了。

在尝试找到罪魁祸首或添加任何变通方法之前，首先应检查问题是否仍然出现在Mono 3.2中，这是最后一个稳定版本（类似于LTS）。

Webclient.UploadString在后续调用中获取System.Net.WebException：ReceiveFailure

1 个答案: