private static void GetResponseAsync(HttpWebRequest request, string method,
ref BackgroundWorker bw, ref DoWorkEventArgs e, out string pointer, out string error)
{
const string SOURCE = CLASS_NAME + "GetResponseAsync";
pointer = "";
error = "";
try
{
//make async call to get response
//then we can abort if Cancel is called on the background worker
var state = new RequestState
{
Request = request,
Method = method
};
_callbackDone = new ManualResetEvent(false);
IAsyncResult ar = request.BeginGetResponse(
ResponseCallback, state);
//poll every 250 ms
const int WAIT = 250;
int cycles = 0;
ar.AsyncWaitHandle.WaitOne(WAIT, true);
while (ar.IsCompleted != true)
{
cycles += 1;
//check for manual/application Cancel
if (bw.CancellationPending)
{
request.Abort();
e.Cancel = true;
Logger.Info(SOURCE, string.Format(
"aborting request for {0} in response to CancellationPending flag",
method));
return;
}
if (cycles >= 120)
{
//enforce timeout of 30 seconds (120 * 250ms)
request.Abort();
Logger.Info(SOURCE, string.Format(
"request for {0} timed out after {1} sec",
method, (cycles * WAIT / 1000)));
error = "request timed out";
return;
}
//wait for another 250 ms
ar.AsyncWaitHandle.WaitOne(WAIT, true);
}
_callbackDone.WaitOne();
_callbackDone.Close();
_callbackDone = null;
using (var response = state.Response)
{
if (response != null)
{
//read the response stream
var stream = response.GetResponseStream();
if (stream != null)
{
using (var reader = new StreamReader(stream))
{
var responseText = reader.ReadToEnd();
Logger.Verbose(SOURCE, string.Format("response for {0} = {1}",
method, responseText));
switch (method)
{
case "UpdateContent":
error = ParseUpdateResponse(responseText);
break;
case "ReceiveSegment":
error = ParseSegmentResponse(responseText);
break;
default:
ParsePostResponse(responseText, ref pointer, out error);
break;
}
}
}
}
else
{
//treat this as an error
Logger.Warning(SOURCE, string.Format(
"no response for {0}", method));
error = "No response";
}
}
}
catch (WebException wex)
{
//exception will be raised if the server didn't return 200 - OK
//try to retrieve more information about the network error
if (wex.Response != null)
{
try
{
var errResponse = (HttpWebResponse)wex.Response;
error = string.Format("code:{0}; desc:{1}",
errResponse.StatusCode,
errResponse.StatusDescription);
}
catch (Exception ex)
{
Logger.Error(SOURCE, ex.ToString());
}
}
else
{
error = wex.ToString();
}
}
catch (Exception ex)
{
error = ex.ToString();
Logger.Error(SOURCE, ex.ToString());
}
}
private static HttpWebRequest CreateRequestAsync(string server, string port, byte[] postData,
ref BackgroundWorker bw, ref DoWorkEventArgs e)
{
const string SOURCE = CLASS_NAME + "CreateRequestAsync";
HttpWebRequest request = null;
try
{
if (!server.Contains("://")) server = "https://" + server;
var route = Properties.Settings.Default.Route;
if (route != "DynamicContentServer/ContentServer")
{
Logger.Verbose(SOURCE,"submitting request to " + route);
}
var uri = new Uri(string.Format("{0}:{1}/{2}",
server, port, route));
request = WebRequest.Create(uri) as HttpWebRequest;
if (request == null) return null;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = postData.Length;
request.AllowWriteStreamBuffering = false;
var state = new RequestState
{
Request = request,
Data = postData
};
//request.KeepAlive;
//request.Proxy;
request.UserAgent = "outlook";
//use manual reset event to signal when callback is complete
_callbackDone = new ManualResetEvent(false);
//initiate callback for the request stream
var ar = request.BeginGetRequestStream(
RequestStreamCallback, state);
//this will signal when the callback fires, but before the data gets written to the stream
//poll every 50 ms
var cycles = 0;
const int WAIT = 50;
ar.AsyncWaitHandle.WaitOne(WAIT, true);
while (ar.IsCompleted != true)
{
cycles++;
if (bw.CancellationPending)
{
request.Abort();
e.Cancel = true;
Logger.Info(SOURCE,
"aborting call for RequestStream in response to CancellationPending flag");
break;
}
if (cycles >= 600)
{
//enforce timeout of 30 seconds (600 * 50ms)
request.Abort();
Logger.Info(SOURCE, string.Format(
"aborting call for RequestStream after {0} sec timeout",
cycles * WAIT / 1000));
break;
}
//wait for another 50 ms
ar.AsyncWaitHandle.WaitOne(WAIT, true);
}
//wait for the callback to signal completion
_callbackDone.WaitOne();
_callbackDone.Close();
_callbackDone = null;
}
catch (Exception ex)
{
Logger.Error(SOURCE, string.Format(
"WebRequest.Create failed using '{0}:{1}', ContentLength {2}: {3}",
server, port, postData.Length, ex.Message));
}
return request;
}
