Question

I need a rewrite rule that will take a folder (dynamic) and rewrite it to a subdomain, it also needs to be transparent to the user (proxy).

Here are some examples:

Example 1

http://admin.domain.com/a/foo 

Should proxy to:

http://a.admin.domain.com/foo    

Example 2

http://admin.domain.com/12345/foo 

Should proxy to:

http://12345.admin.domain.com/foo

Basically the first folder in the path is being used as the subdomain and the rest of the path is left as is.

Answer 1

Try adding this to the .htaccess file in your document root:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^admin\.domain\.com$  [NC]
RewriteRule ^([^/]+)/(.*)$ http://$1.admin.domain.com/$2  [P,L]

If you want to add this to your server config or vhost config, add a “/” in front of the regex so that it looks like this: ^/([^/]+)/(.*)$.