C# - Connection: keep-alive Header is Not Being Sent During HttpWebRequest

Question

I'm trying to send to send the following header with my HttpWebRequest:

Connection: keep-alive

However, the header is never sent. Fiddler2 is showing that whenever I request the page in Google Chrome, the header is sent. However, my application refuses to send this header for some reason.

I have set the KeepAlive property to true (it's true by default anyway), yet the header still does not get sent.

I am trying to send this header with multiple HttpWebRequests, but they all basically look like this:

HttpWebRequest logIn6 = (HttpWebRequest)WebRequest.Create(new Uri(responseFromLogIn5)); logIn6.CookieContainer = cookies; logIn6.KeepAlive = true; logIn6.Referer = "https://login.yahoo.com/config/login?.src=spt&.intl=us&.lang=en-US&.done=http://football.fantasysports.yahoo.com/"; logIn6.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.220 Safari/535.1"; logIn6.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"; logIn6.Headers.Add("Accept-Encoding:gzip,deflate,sdch"); logIn6.Headers.Add("Accept-Language:en-US,en;q=0.8"); logIn6.Headers.Add("Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3"); logIn6.AllowAutoRedirect = false;  HttpWebResponse logIn6Response = (HttpWebResponse)logIn6.GetResponse(); string responseFromLogIn6 = logIn6Response.GetResponseHeader("Location");  cookies.Add(logIn6Response.Cookies);  logIn6Response.Close(); 

Does anyone know what I have to do to make sure this header is sent?

Fiddler2 Raw From Chrome:

GET xxx HTTP/1.1 Host: accounts.google.com Connection: keep-alive Referer: https://login.yahoo.com/config/login?.src=spt&.intl=us&.lang=en-US&.done=http://football.fantasysports.yahoo.com/ User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.220 Safari/535.1 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: xxx  HTTP/1.1 302 Moved Temporarily Set-Cookie: xxx Set-Cookie: xxx Location: xxx Content-Type: text/html; charset=UTF-8 P3P: CP="This is not a P3P policy! See http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info." Date: Sat, 17 Sep 2011 22:27:09 GMT Expires: Sat, 17 Sep 2011 22:27:09 GMT Cache-Control: private, max-age=0 X-Content-Type-Options: nosniff X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block Content-Length: 2176 Server: GSE 

Fiddler2 Raw From My Application:

GET xxx HTTP/1.1 Referer: https://login.yahoo.com/config/login?.src=spt&.intl=us&.lang=en-US&.done=http://football.fantasysports.yahoo.com/ User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.1 (KHTML, like Gecko) Chrome/13.0.782.220 Safari/535.1 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Host: accounts.google.com  HTTP/1.1 302 Moved Temporarily Location: xxx Content-Type: text/html; charset=UTF-8 Date: Sun, 18 Sep 2011 00:05:40 GMT Expires: Sun, 18 Sep 2011 00:05:40 GMT Cache-Control: private, max-age=0 X-Content-Type-Options: nosniff X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block Content-Length: 573 Server: GSE 

I'm trying to get the second Fiddler2 raw information to look like the first Fiddler2 raw information.

Answer 1

I've had the same issue: The Connection: Keep-Alive header is not sent except the first request, and the server I accessed won't give me the correct response if it is missing. So, here are my workarounds to this issue:

First is set the ProtocolVersion property of HttpWebRequest instance to HttpVersion.Version10. Except the http command will become GET xxx HTTP/1.0, it works and uses only the public API.

The second way uses the reflection to modify the internal property ServicePoint.HttpBehaviour of HttpWebRequest instance, like this:

var req = (HttpWebRequest)WebRequest.Create(someUrl);  var sp = req.ServicePoint; var prop = sp.GetType().GetProperty("HttpBehaviour",                          BindingFlags.Instance | BindingFlags.NonPublic); prop.SetValue(sp, (byte)0, null);  req.GetResponse().Close(); 

Hope this helps.

Answer 2

I struggled with this problem for half a day! And dear old Fiddler (my guardian angel) was inadvertantly part of the problem:

Whenever I tested my HTTP POSTs using Fiddler monitoring ON - the problem DIDN'T appear Whenever I tested my HTTP POSTs with Fiddler monitoring OFF - the problem DID appear

My POSTS were sent with protocol 1.1 and the Keep-Alive was ignored/redundant/why after the initial connection. i.e. I could see it in the header of the first POST (via Fiddler!), but not in subsequent POSTs despite using the same code. Hey ho ...

But the remote server would only respond if Keep-Alive was sent. Now I can't prove this, but I suspect that Fiddler monitoring the connection caused the remote server to think or believe that the connection was still active (despite no Keep-Alives sent after my first POST) and responded correctly. As I said, the second I turned Fiddler off, the absence of Keep-Alives caused the remote server to timeout on me..

I implemented the 1.0 solution described above and my POSTS now work, with or without Fiddler on or off. Hope this helps somebody else stuck somewhere ...