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c#httpwebrequestasync-await

Timeout behaviour in HttpWebRequest.GetResponse() vs GetResponseAsync()

When I try the following code:

var request = (HttpWebRequest)HttpWebRequest.Create(url);
request.Timeout = 3; // a small value

var response = request.GetResponse();
Console.WriteLine(response.ContentLength);

for a URL that I know it is going to take more than 3 millisecond to load (I put a Thread.Sleep(110000) in Application_BeginRequest) it works fine and throws a WebException as expected.

Problem is when I switch to async method:

var response = request.GetResponseAsync().Result;

or

var response = await request.GetResponseAsync();

This async version completely ignores any Timeout value, including ReadWriteTimeout and ServicePoint.MaxIdleTime

I couldn't find anything about Timeout in MSDN's GetResponseAsync() now I'm wondering if it is a bug in GetResponseAsync() or something is wrong in the way I use async here?

Solution

  • Timeout does not apply to asynchronous HttpWebRequest requests. To quote the docs:

    The Timeout property has no effect on asynchronous requests

    I recommend you use HttpClient instead, which was designed with asynchronous requests in mind.