Help With HTTP_RESPONSE

when HTTP_REQUEST {
    Save host (without the port if it's specified)
   set shost [getfield [HTTP::host] ":" 1]
}
when HTTP_RESPONSE {
    Check if response is a redirect (HTTP status of 3xx)
   if { [HTTP::status] starts_with "3" } {
       Check if the port the request was made on was 443
      if {[clientside {TCP::local_port}] == 443}{
          Request was made to an SSL port, so replace 127.0.0.1 with the Host header value from the request
            and replace http:// with https:// in the Location header value
         HTTP::header replace Location [string map "http:// https:// 127.0.0.1 $shost" [HTTP::header value Location]]
      } else {
          Request was made to an HTTP port, so just replace 127.0.0.1 with the Host header value from the request
         HTTP::header replace Location [string map "127.0.0.1 $shost" [HTTP::header value Location]]
      }
   }
}