How VHM works

Virtual hosting with Zope

The VHM part of an ordinary rewrite rules looks like this:

^/(.*) \
http://localhost:10080/VirtualHostBase/http/www.example.org:80/example_site/VirtualHostRoot/$1

The address has seven parts:

http://localhost:10080

This is only for apache's mod_proxy module. It configures what server should be accessed including protocol, host and port. In this example mod_proxy is accessing the ZServer at port 100080 on the same host using http.

VirtualHostBase

This is the magic keyword to start virtual hosting. You must not add an object called VirtualHostBase to your zope root!

http

The first path segment after VirtualHostBase defines the protocol of the vhost url.

www.example.org:80

The second segment after VirtualHostBase defines the server and the port. Together with the protocol it's the base part of the url, in this example http://www.example.org:80. Like VirtualHostBase the protocol and server are no real objects. They are just put into the url for configuration purpose and they are stripped of the url after configuring the virtual host for a request.

example_site

Now the real traversal through Zope starts. After setting up the protocol and server part of the new url we are traversing through Zope to the new virtual root for the vhost. You can add zero or more objects here.

VirtualHostRoot

Finally the magic keyword that we have reached the new virtual root for the vhost. Everything after VirtualHostRoot is visible to the browser.

$1 and ^/(.*)

$1 and ^/(.*) are some regex foo. ^/(.*) means "Match everything starting with a / and save every char after the / in the var $1.

Special case _vh_foo

Imagen you want to have http://www.example.org/foo/ as the root url of your virtual url. You can get the effect by using the special _vh_ declaration. Any path segment starting with _vh_ is stripped of the url for traversal through zope and readded without _vh_ after traversal. Example:

^/foo/(.*) \
http://localhost:10080/VirtualHostBase/http/www.example.org:80/example_site/VirtualHostRoot/_vh_foo/$1

Note You are neither allowed to create an object called VirtualHostBase or VirtualHostRoot in your zope nor should you add an object with the same id of your VHM. It may work but it may also break your site.