Subdomain iRule question

You can get or set the HTTP host using HTTP::host. The URI can be gotten or set using HTTP::uri.

You can use getfield to pick out the parts of the host and then prepend them to the URI. You may want to add additional logic to handle the possibility that the host might not contain a string you want to prepend to the URI. For example, if a client requests http://www.example.com/someuri, you may not want to redirect them to http://example.com/www/someuri.

Here's an example to get you started:

when RULE_INIT {
    Set the value for the domain with a leading period
      We'll check the host header value for any string the comes before this string 
      and prepend it to the URI
   set ::domain ".example.com"
}
when HTTP_REQUEST {
   if { [string tolower [HTTP::host]] ends with $::domain }{
       Get any part of the host that comes before the domain.
         Split the URI using the domain string.  Grab the first string that comes before the domain
      set subdomain [getfield [HTTP::host] $::domain 1]
       If subdomain isn't null, prepend it to the URI 
         You could also add additional checks here like subdomain doesn't equal       "www"
      if { not ($subdomain == "") }{
 HTTP::uri [concat "/$subdomain[HTTP::uri]"]
          Set the HTTP host to the domain
         HTTP::host [string range $::domain 1 end]
      }
   }
}

Edit: I forgot to change the host header to the domain only

Aaron