ProxyPreserveHost on individual proxypass rules

Question

I have two proxypass rules on my web host, one that points to a local varnish instance for caching purposes, which I want ProxyPreserveHost enabled for, and another that points to a third party hosted site, which I want ProxyPreserveHost disabled for. Is there anyway I can do this on a per rule/pass basis?

Answer 1

Under Apache 2.2, no - the ProxyPreserveHost directive is only valid in the server config or virtual host contexts; you'd need the different ProxyPass statements to be in different virtual hosts.

In Apache 2.4, yes - the directory context has been added for the directive, so you can now do something such as:

<Location /to-varnish/>
    ProxyPreserveHost On
    ProxyPass http://127.0.0.1:8000/to-varnish/
</Location>
<Location /to-third-party/>
    ProxyPreserveHost Off
    ProxyPass http://third-party-site.com/
</Location>

Answer 2

You can with help of RequestHeader

ProxyPreserveHost On
<LocationMatch third-party-pattern>
   RequestHeader  set  Host  third-party-vhost-name
   ProxyPassMatch  http://third-party-server
</LocationMatch>
<LocationMatch varnish-pattern>
   ProxyPassMatch  http://varnish-server
</LocationMatch>

Answer 3

I'm unable to upvote Sorin's response...

In our local situation running Apache 2.2, and the primary app requires proxypreservehost (CQ/AEM author) to login, but a partner we proxy to requires their host in the host header.

We don't need to do this with regex though, a regular <Location...> works fine.

From documentation (http://httpd.apache.org/docs/2.2/mod/core.html#location):

The directive limits the scope of the enclosed directives by URL.

This solution works for us:

  <Location /[path]/ >
    RequestHeader set Host [thirdparty]
  </Location>
  RewriteRule ^/[path]/(.*) https://[thirdparty]/$1 [P,NC,L]

This sets the host header for this request to the partner's hostname.

With that in place, we can continue to login to CQ/AEM author AND proxy to the partner service using their expected host header.