Last summer I wrote several posts on using HttpWebRequest and SOAP proxies.  Recently I was working on code that needed to handle requests that could take a really long time for the server to process.  The client would give up and close the network connection long before the request completed.

The code had tried to control that using the HttpWebRequest.Timeout property.  That helped, but it didn’t solve the problem.  Without changing the Timeout property, the client gave up after 100 seconds, which is the default value for that property as stated in the docs.  The Timeout property was set to infinite, but the client gave up after five minutes.  Below is the doc for the Timeout property.

Return Value

The number of milliseconds to wait before the request times out. The default is 100000 milliseconds (100 seconds).

Remarks

Timeout is the number of milliseconds that a synchronous request made with the GetResponse method waits for a response, and the GetRequestStream method waits for a stream. If the resource is not returned within the time-out period, the request throws a WebException with the Status property set to Timeout.

The Timeout property has no effect on asynchronous requests made with the BeginGetResponse or BeginGetRequestStream methods.

Caution In the case of asynchronous requests, it is the responsibility of the client application to implement its own timeout mechanism. Refer to the example in the BeginGetResponse method.

To specify the amount of time to wait before a read or write operation times out, use the ReadWriteTimeout property.

At the end of that, notice that they mention another timeout value, the HttpWebRequest.ReadWriteTimeout property.  Here’s the doc for that.

Return Value