TaskFactory.FromAsync with BeginGetRequestStream/EndGetRequestStream hangs

Question

I have a method like this, that hangs when declaring responseObject using Task.Factory.FromAsync()

private async Task post(string          


        

Answer 1

First of all: Don't use ".Result" in async methods. This will block the thread that is running your method. Use "await" instead, so the thread jumps back to your method when the result is acquired.

The problem with your code is that you open a request stream, but you never close it. So when should it expect to finish your request and send it? It'll always expect more input to come, until the request runs in a timeout. Also you have not set a content-type and content-length.

private async Task<string> post(string url, string postdata)
    {
        var request = WebRequest.Create(new Uri(url)) as HttpWebRequest;
        request.Method = "POST";

        byte[] data = Encoding.UTF8.GetBytes(postdata);
        request.ContentLength = data.Length;

        using (var requestStream = await Task<Stream>.Factory.FromAsync(request.BeginGetRequestStream, request.EndGetRequestStream, request))
        {
            await requestStream.WriteAsync(data, 0, data.Length);
        }


        WebResponse responseObject = await Task<WebResponse>.Factory.FromAsync(request.BeginGetResponse, request.EndGetResponse, request);
        var responseStream = responseObject.GetResponseStream();
        var sr = new StreamReader(responseStream);
        string received = await sr.ReadToEndAsync();

        return received;
}