Redirect to test server and rewrite returned links

when HTTP_REQUEST {
    set DEBUG 1
    if { [HTTP::version] equals "1.1" } {
        if { [HTTP::header is_keepalive] } {
            HTTP::header replace "Connection" "Keep-Alive"
            HTTP::header remove Accept-Encoding
        }
        HTTP::version "1.0"
        set collected 0
    }
    if { [HTTP::host] equals "devserverurl"} {
        HTTP::header replace "Host" "serverurl"
        if { $DEBUG } { log local0. "irule used by IP: [IP::client_addr] - requesting [HTTP::host][HTTP::uri]" }
    }
}
when HTTP_RESPONSE {
     Get the content length so we can request the data to be
     processed in the HTTP_RESPONSE_DATA event.
    set DEBUG 1
    if { [HTTP::header exists "Content-Length"] } {
        set content_length [HTTP::header "Content-Length"]
    } else {
        set content_length 0
    }
     content_length of 0 indicates chunked data (of unknown size)
    if { $content_length > 0 && $content_length < 1024001 } {
         set collect_length $content_length
     } else {
         set collect_length 1024000
     }
     if { $DEBUG } {
         log local0. "[IP::client_addr]:[TCP::client_port]: Content Length:: $content_length    Collect Length: $collect_length"
     }
    if { $collect_length > 0 } {
        HTTP::collect $collect_length
    }
}
when HTTP_RESPONSE_DATA {
    set DEBUG 1
   regsub -all "serverurl" [HTTP::payload] "devserverurl" newdata
    if { $DEBUG } {
         log local0. "PAYLOAD before replace: [HTTP::payload]"
    }
    HTTP::payload replace 0 $content_length $newdata
    if { $DEBUG } {
         log local0. "PAYLOAD after replace: [HTTP::payload]"
     }
     HTTP::release
      if { $content_length > 0 } {
         for unchunked data, calculate the remaing length & re-collect if necessary
         the HTTP_RESPONSE_DATA event will be triggered again when each collection is complete
         set collect [expr {$collected + $collect_length}]
         set remaining [expr {$content_length - $collected}]
         if { $remaining > 0 } {
             if { $remaining < $collect_length } {
                 set collect_length $remaining
             }
             HTTP::collect $collect_length
         }
     } else {
     chunked responses data, continue collecting in 1MB chunks.  Watch for hanging responses here.
     The HTTP_RESPONSE_DATA event will be triggered again when each ccollection is complete
         HTTP::collect $collect_length
     }
}