Re: WebException thrown by HttpWebRequest.GetResponse() method

Sergey Shcherbakov via .NET 247 wrote:

> Hi,
>
> I have a problem using HttpWebRequest class.
> I create an application, which communicates with a network device
> (not a PC), which has a built in HTTP 1.1 server listening on port
> 80. For some requests, which I send to the server it answers with a
> short byte sequence:
>
> HTTP/1.1 200 OK\r\n
>
> and that's it, no more data (I check network traffic using Ethereal
> network monitor). In case of such response from the server, I get a
> WebException on a call to HttWebRequest.GetResponse() method saying:
> "The underlying connection was closed: An unexpected error occured on
> a receive". If there are some data coming from server, then
> GetResponse() method returns instance of HttpWebResponse properly.
>
[...]
> Actually, I am not completely sure, whether the problem is im my
> code, .NET framework or device HTTP server, because exception occurs
> immediately after a call to GetResponse() and the device usually
> answers with "HTTP/1.1 200 OK\r\n" after a approximately 5 seconds
> timeout, because of processing of input data. So the GetResponse()
> does not wait for response and just throws exception. It does not
> happen with this code when the server returns some data. Could you
> please give me a hint: 1) Am I correctly using HttpWebrequest to
> write data to the remote server? 2) How to make my code block and
> wait untill "HTTP/1.1 200 OK\r\n" response comes from the server?
> (The server becomes unavailable untill it processes all input data
> sent by me and I can not send next requests to it untill this one
> ends with 200 OK)

Your code is fine. This is a server error. The HTTP response shown
above is a protocol violation.

A HTTP 1.1 response must either contain
a) a valid Content-Length header or
b) a Connection: close header or
c) a Transfer-Encoding: chunked header (and a chunked response of
course)

You can try to work around this bug by setting HttpWebRequest.KeepAlive
to false or instead use HTTP 1.0 as protocol version.

Cheers,
--
http://www.joergjooss.de
mailto:news-reply@xxxxxxxxxxxxx
.

Relevant Pages