exception logic for selective https redirect

First, I saw a more eloquent way to parse the subdomain from the getfield wiki page (Click here)"

[getfield [string tolower [HTTP::host]] "example.com" 1]

This would set the host header value to lower case and then split the value on the literal string "example.com" and return the 1st field (the subdomain).

You can use a class (called a datagroup in the GUI) which contains the subdomains you want to redirect. You can create a datagroup under Local Traffic >> iRules >> Datagroups.

You can then use matchclass (Click here) to check if the requested host starts with one of the subdomains in the class.

class redirect_hosts {
   subdomain1.
   subdomain2.
   subdomain3.
}

when HTTP_REQUEST {
   if {([matchclass [getfield [string tolower [HTTP::host]] "example.com" 1]] equals $::redirect_hosts) and (not ([HTTP::uri] contains "SpecialUrl"))} {
      HTTP::redirect https://[HTTP::host][HTTP::uri]
   }
}

The class approach is cleaner as far as the rule goes. But it might be slightly faster to use an if and then a switch statement:

if {not ([HTTP::path] contains "SpecialUrl")}{
    use getfield to split the host header value and grab anything that comes before "example.com"
    set that remaining string to lower case
   switch [getfield [string tolower [HTTP::host]] "example.com" 1] {
      subdomain1. -
      subdomain2. -
      subdomain3. {
          redirect matching requests to https
         HTTP::redirect https://[HTTP::host][HTTP::uri]
      }
      default {
          do nothing; let request be sent to pool per VIP configuration
      }
   }
}

[edited to fix the order of string tolower and getfield]

Aaron