HttpWebRequest.BeginGetResponse doesn´t respect any Timeout properties from HttpWebRequest(Timeout or ReadWriteTimeout).
I read some approaches to get the same results, but I don't know if it's the best way to do it and if I should use for few calls or I can scale it inside loops(I am doing a webcrawler).
The important thing is, initially my code isn´t async, I just need async because my method should accept a CancellationToken.
My concern is about WaitHandles and ThreadPool.RegisterWaitForSingleObject. It isn´t a daily code then I don´t know if I can have problems in the near future.
private static void HandleCancellation(HttpWebRequest request, IAsyncResult getResponseResult, CancellationToken cancellationToken)
{
using (WaitHandle requestHandle = getResponseResult.AsyncWaitHandle)
{
ThreadPool.RegisterWaitForSingleObject(requestHandle, TimeoutCallback, request, request.Timeout, true);
//If request finish or cancellation is called
WaitHandle.WaitAny(new[] {requestHandle, cancellationToken.WaitHandle});
}
//If cancellation was called
if (cancellationToken.IsCancellationRequested)
{
request.Abort();
cancellationToken.ThrowIfCancellationRequested();
}
}
Calling(again, it isn´t async)
IAsyncResult getResponseResult = request.BeginGetResponse(null, null);
HandleCancellation(request, getResponseResult, cancellationToken);
return (HttpWebResponse)request.EndGetResponse(getResponseResult);
Reference: Better approach in management of multiple WebRequest
The MSDN documentation for BeginGetResponse has a very good example of how to handle timeouts. It worked quite well for me in my Web crawler.