Irule not working

Just a quick rewrite:

when HTTP_REQUEST {
    set xyz ""
    HTTP::header insert "clientless-mode" 1
    log local0. "clientless-mode 1"
    set xyz [HTTP::query]
}

when ACCESS_POLICY_COMPLETED {
    if { $xyz ne "" } {
        log local0. "ACCESS_POLICY_COMPLETED: Found query string $xyz."
        if {[ACCESS::policy result] equals "allow"} {
            set abc ""
            set abc [class match -value -- "$xyz" equals USERS_DG]
            if { $abc ne "" } {
                log local0. "ACCESS_POLICY_COMPLETED: $abc : access allowed"
                ACCESS::respond 200 content $abc
                event disable all
                return
            } else {
                log local0. "ACCESS_POLICY_COMPLETED: param not matching acl: access not allowed"
                ACCESS::respond 404 "resource not found."
                event disable all
                return
            } 
        }
    } else {
        log local0. "ACCESS_POLICY_COMPLETED: query string not found."
        ACCESS::respond 404 "resource not found." 
        event disable all
        return
    }
}