Question

当我将HttpWebRequest发送到无法访问的Web服务器时，它会按预期超时，但只要Web服务器联机就会重新发送。 Web服务器尝试读取导致HttpListnerException且错误代码为995的请求正文。

System.Net.HttpListenerException (0x80004005): The I/O operation has been aborted because of either a thread exit or an application request.
   at System.Net.HttpRequestStream.Read(Byte[] buffer, Int32 offset, Int32 size)
   at System.IO.StreamReader.ReadBuffer()
   at System.IO.StreamReader.ReadToEnd()

以下是代码：

在Windows Mobile 6.5模拟器上运行的客户端.NET CF 3.5：

var request = (HttpWebRequest)WebRequest.Create("http://servername:9999/");
request.Method = "POST";
request.Timeout = 1000;
var requestBodyBytes = Encoding.UTF8.GetBytes("foobar");
request.ContentType = "text/plain";
request.ContentLength = requestBodyBytes.Length;
using (var requestStream = request.GetRequestStream())
{
    requestStream.Write(requestBodyBytes, 0, requestBodyBytes.Length);
}
using (var response = request.GetResponse())
using (var responseStream = response.GetResponseStream())
using (var responseStreamReader = new StreamReader(responseStream))
{
    return responseStreamReader.ReadToEnd();
}

服务器.NET Framework 4.5：

using (var listener = new HttpListener())
{
    var shutdown = new ManualResetEvent(false); 
    var worker = new Thread(() =>   
    {
        var signals = new WaitHandle[] { shutdown, null };
        listener.Prefixes.Add("http://servername:9999/");       
        listener.Start();
        for (;;)
        {
            try     
            {
                var contextResult = listener.BeginGetContext(null, null);
                signals[1] = contextResult.AsyncWaitHandle;
                if (WaitHandle.WaitAny(signals) == 0)
                    return;     
                var context = listener.EndGetContext(contextResult);
                var request = context.Request;
                using (var requestStream = request.InputStream)
                using (var requestStreamReader = new StreamReader(requestStream))
                {
                    requestStreamReader.ReadToEnd();
                }
                var responseBytes = Encoding.UTF8.GetBytes(String.Format("Hello {0}", DateTime.Now));
                using (var response = context.Response)
                using (var responseStream = response.OutputStream)
                {
                    response.ContentType = "text/plain";
                    response.ContentLength64 = responseBytes.Length;
                    responseStream.Write(responseBytes, 0, responseBytes.Length);
                }
            }
            catch (Exception e)
            {
                // The HttpListenerException mentioned above gets thrown here.
                MessageBox.Show(e.ToString());
            }
        }
    });
    worker.Start();
    MessageBox.Show("Click OK to exit.");
    shutdown.Set();
    worker.Join();
}

要重现错误，我必须执行以下操作：

在启动Web服务器之前发送一个或多个Web请求，这会导致客户端出现WebException，因为请求超时
不要关闭客户端应用程序
启动网络服务器
观察WebServer接收客户端先前发送的Web请求并尝试读取请求正文，从而导致上述HttpListenerException

仅当我使用Compact Framework在Windows Mobile设备上运行客户端代码而在桌面上运行它时，才会出现此错误。

如何阻止Windows Mobile客户端重新发送超时请求？

失败的HttpWebRequest会自动重新发送

0 个答案: