c# asynchronous http request

Question

I am trying to make asynchronous call to some server so that the main thread does not stop for the request.

I created my request something like this :

//Create Request
 HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
 request.Method = method;
 request.ContentType = "application/XML";
 System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
 byte[] bytes = encoding.GetBytes(data);
 request.ContentLength = bytes.Length;
 try
 {
 using (Stream requestStream = request.GetRequestStream())
 {
 // Send the data.
 requestStream.Write(bytes, 0, bytes.Length);
 }
 request.BeginGetResponse((x) =>
 {
 using (HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(x))
 {
 if (callback != null)
 {
 callback(response.GetResponseStream());
 }
 }
 }, null);
 }
 catch (Exception ex)
 {
 //TODO: Log error
 }

But still the thread stops for some time in this request. Especially on the line using

(Stream requestStream = request.GetRequestStream())

Is there any way by which we can make it completely asynchronous or some other better way so that our main thread does not hangs for this request.

• Daniel Kelley: Sure - call GetRequestStreamAsync and await the result.
• Luaan: Or just use HttpClient and await if you can - it's much more concise.
• Jim Mischel: The documentation says that if you call GetRequestStream then you must call GetResponse to get the response. If you want an asynchronous response using BeginGetResonse, then you must call BeginGetRequeststream to get the request stream.

Answer 1

using (HttpClient client = new HttpClient())
{
 var content = new StringContent(data, Encoding.UTF8, "application/xml");
 var response = await client.PostAsync(uri, content);
 var respString = await response.Content.ReadAsStringAsync();
}

• user2692032: I am little confused here. In the request we actually wait for the response by putting await. Also if method A() makes the request then we have to call by await task A() and then wait for the response. Making it synchronous only.
• EZI: @user2692032 What Happens in an Async Method

Answer 2

Need to use the async methods and await them.

using (var stream = await request.GetRequestStreamAsync())
{
 await stream.WriteAsync(bytes, 0, bytes.Length);
}

Answer 3

Here is a simple sample which I am using to make async request. Mark your method with async keyword

using (var httpClient = new HttpClient())
{
 string requestContent = string.Empty; // JSON Content comes here
 HttpContent httpContent = new StringContent(requestContent, Encoding.UTF8, "application/json");
 HttpRequestMessage httpRequestMessage = new HttpRequestMessage(Verb, url);
 httpRequestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
 httpRequestMessage.Content = request.Verb == HttpMethod.Get ? null : httpContent;
 response = httpClient.SendAsync(httpRequestMessage);
 var responseContent = await response.Result.Content.ReadAsStringAsync();

}