Re: HttpWebRequest headers problem

From: Joerg Jooss (joerg.jooss_at_gmx.net)
Date: 09/17/04 

Date: Fri, 17 Sep 2004 11:40:26 +0200

Dunc wrote:
> Hi,
>
> I'm using a c# app to download zipped XML data from a 3rd party. All
> is good, but the XML is generated on the remote machine at the time
> of request (hence the huge timeout), and when it sends me the file,
> it has an error message appended to the beginning:
>
> ÿþ<br />
> <b>Warning</b>: HTTP_USER_AGENT variable is not set, cannot
> determine user agent name in
> <b>/home/sites/site2/web/check_auth.inc.php</b> on line <b>19</b><br
> />
>
> I can successfully get the file if I do it manually through IE, so
> it's not a problem on the client end. I've tried adding the
> HTTP_USER_AGENT header to the request object, but no luck getting rid
> of it. How do I add the correct request headers here? I've put the
> code (which is pretty simple) below.
[...]

HTTP_USER_AGENT is a probably a CGI variable, but not a HTTP header name.
Use
HttpWebRequest.UserAgent to set the user agent.

And "IE" is not a proper user agent string. Try
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)"
-- that's IE 6 SP2 on Win XP SP2.

>
> ---/ snip /---
>
> HttpWebRequest request =
> (HttpWebRequest)WebRequest.Create(strRemoteURI);
>
> // Set some reasonable limits on resources used by this request
> request.MaximumAutomaticRedirections = 4;
> request.MaximumResponseHeadersLength = 64;
> request.Timeout = 600000;
>
> // Set credentials to use for this request.
> request.Credentials = CredentialCache.DefaultCredentials;
> request.Headers.Add("HTTP_USER_AGENT", "IE");
> HttpWebResponse response = (HttpWebResponse)request.GetResponse();
>
> // Get the stream associated with the response.
> Stream receiveStream = response.GetResponseStream();
>
> // Pipes the stream to a higher level stream reader with the required
> encoding format.
> StreamReader readStream = new StreamReader (receiveStream,
> System.Text.Encoding.Unicode);
> StreamWriter writeStream = new StreamWriter("_" + strFileName, false,
> System.Text.Encoding.Unicode);

Ouch! Don't use Readers and Writers to handle binary content.

Cheers, 

-- 
Joerg Jooss
joerg.jooss@gmx.net

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