Irule with regex filtering migrate from netscaler

If you break it down like this:

HTTP.
    REQ.
        URL.
            PATH_AND_QUERY.
                AFTER_REGEX(re/\?/).
                BEFORE_REGEX(re/:/).
                REGEX_MATCH(re/(action$|redirect$|redirectAction$)/)

And based on this reference:

http://support.citrix.com/proddocs/topic/netscaler-policy-configuration-93-map/ns-regex-operations-con.html

I think what it's basically saying is this:

1. Start with the full HTTP request URI (path, query string, and all)
2. From that, return the string that is after the question mark (?)
3. From that, return the string that is before the colon (:)
4. And if the resulting string ends with ($) "action", or "redirect", or "redirectAction", then drop the request.

So then the resulting iRule might look like this:

when HTTP_REQUEST {
    if { [regexp -all {(action|redirectaction|redirect)} [string tolower [findstr [HTTP::uri] "?" 1 ":"]]] > 0 } {
        drop
    }
}

Or, if you wanted to avoid the regex:

when HTTP_REQUEST {
    if { ( [string tolower [findstr [HTTP::uri] "?" 1 ":"]] ends_with "action" ) or ( [string tolower [findstr [HTTP::uri] "?" 1 ":"]] ends_with "redirect" ) or ( [string tolower [findstr [HTTP::uri] "?" 1 ":"]] ends_with "redirectaction" ) } {
        drop
    }        
}

Or:

when HTTP_REQUEST {
    switch -glob [string tolower [findstr [HTTP::uri] "?" 1 ":"]] {
        "*action" -
        "*redirect" -
        "*redirectaction" {
            drop
        }
        default {
            return
        }
    }
}