/// <summary>
/// This method does an Http GET to the provided url and calls the responseCallback delegate
/// providing it with the response returned from the remote server.
/// </summary>
/// <param name="url">The url to make an Http GET to</param>
/// <param name="timeout">The timeout.</param>
/// <param name="responseCallback">The callback delegate that should be called when the response returns from the remote server</param>
/// <param name="state">Any state information you need to pass along to be available in the callback method when it is called</param>
/// <param name="contentType">The Content-Type of the Http request</param>
public static void GetAsync(string url, TimeSpan timeout, Action<HttpWebRequestCallbackState> responseCallback, object state = null, string contentType = "application/x-www-form-urlencoded")
{
HttpWebRequest httpWebRequest;
try
{
httpWebRequest = CreateHttpWebRequest(url, "GET", contentType);
}
catch (Exception ex)
{
Log.WarnFormat("Exception creating WebRequest for url: {0}", ex, url);
responseCallback(new HttpWebRequestCallbackState(ex, state));
return;
}
var requestState = new HttpWebRequestAsyncState
{
HttpWebRequest = httpWebRequest,
ResponseCallback = responseCallback,
State = state
};
#if DISABLE_ASYNC
ProcessRequest(requestState);
#else
var result = httpWebRequest.BeginGetResponse(BeginGetResponseCallback, requestState);
ThreadPool.RegisterWaitForSingleObject(result.AsyncWaitHandle, TimeOutCallback, httpWebRequest, timeout, true);
#endif
}
/// <summary>
/// Begins the get response callback.
/// </summary>
/// <param name="asyncResult">The async result.</param>
private static void BeginGetResponseCallback(IAsyncResult asyncResult)
{
WebResponse webResponse = null;
Stream responseStream = null;
HttpWebRequestAsyncState asyncState = null;
try
{
asyncState = (HttpWebRequestAsyncState)asyncResult.AsyncState;
webResponse = asyncState.HttpWebRequest.EndGetResponse(asyncResult);
responseStream = webResponse.GetResponseStream();
var webRequestCallbackState = new HttpWebRequestCallbackState((HttpWebResponse)webResponse, asyncState.State);
asyncState.ResponseCallback(webRequestCallbackState);
responseStream.Close();
responseStream = null;
webResponse.Close();
webResponse = null;
}
catch (Exception ex)
{
if (asyncState != null)
{
Log.WarnFormat("Exception requesting url: {0}", ex, asyncState.HttpWebRequest.RequestUri);
asyncState.ResponseCallback(new HttpWebRequestCallbackState(ex, asyncState.State));
}
else
{
Log.Warn("BeginGetResponseCallback", ex);
throw;
}
}
finally
{
if (responseStream != null)
{
responseStream.Close();
}
if (webResponse != null)
{
webResponse.Close();
}
}
}
static void ProcessRequest(HttpWebRequestAsyncState asyncState)
{
WebResponse webResponse = null;
Stream responseStream = null;
try
{
webResponse = asyncState.HttpWebRequest.GetResponse();
responseStream = webResponse.GetResponseStream();
var webRequestCallbackState = new HttpWebRequestCallbackState((HttpWebResponse)webResponse, asyncState.State);
asyncState.ResponseCallback(webRequestCallbackState);
if (responseStream != null)
responseStream.Close();
responseStream = null;
webResponse.Close();
webResponse = null;
}
catch (Exception ex)
{
if (asyncState != null)
{
Log.WarnFormat("Exception requesting url: {0}", ex, asyncState.HttpWebRequest.RequestUri);
asyncState.ResponseCallback(new HttpWebRequestCallbackState(ex, asyncState.State));
}
else
{
Log.Warn("BeginGetResponseCallback", ex);
throw;
}
}
finally
{
if (responseStream != null)
responseStream.Close();
if (webResponse != null)
webResponse.Close();
}
}
