Force mod_proxy to preserve some response headers

Question

We're using Apache in front of Jenkins. Jenkins' Ajax calls include a n header that apparently needs to survive the roundtrip. If we access Jenkins on port 8080, then the n header is included in the response, if we access it through mod_proxy, the n header is getting stripped.

I tried using mod_headers to preserve this header, but for some reason that doesn't work. Is there any other way I can force mod_proxy to leave this header alone?

Edit 1:

This is the response getting returned by Jenkins.

HTTP/1.1 200 OK
Server: Winstone Servlet Engine v0.9.10
Content-Type: text/html;charset=UTF-8
n: 131
Connection: Close
Date: Tue, 20 Mar 2012 09:53:42 GMT
X-Powered-By: Servlet/2.5 (Winstone/0.9.10)

This is what Apache is returning:

Connection:close
Content-Encoding:gzip
Content-Type:text/html;charset=UTF-8
Date:Tue, 20 Mar 2012 10:37:21 GMT
Transfer-Encoding:chunked
Vary:Accept-Encoding

Edit 2:

It turns out Nginx does pass the appropriate headers back. That's the way I managed to solve it now. Still the original question is relevant: is there any way to get it done using Apache?

Answer 1

I found a way to get around this issue under apache.

it was created by alex (see https://issues.jenkins-ci.org/browse/JENKINS-327 )

basically

1. my jenkins running at "http://localhost:8080/jenkins"

2. I want to access it via jenkins.mydomain.com.

now when I access jenkins.mydomain.com apache will redirect me to jenkins.mydomain.com/jenkins, not perfact but at least works.

<VirtualHost *:80>
ServerName jenkins.mydomain.com
Redirect / http://jenkins.mydomain.com/jenkins
<Location /jenkins>
  ProxyPass http://localhost:8080/jenkins
  ProxyPassReverse http://localhost:8080/jenkins
</Location>
</VirtualHost>

Answer 2

I eventually moved to Nginx. Nginx didn't strip out the headers. Still, it remains weird that you cannot get Apache to leave the n header alone.