wmii+ruby xlock action

I use xscreensaver and like to lock my display when I leave my computer. Here is a snippet from my wmiirc-config.rb file that adds an xlock action to the Alt-a action menu.

    plugin_config["standard:actions"]["internal"].update({
      'xlock' => lambda do |wmii, *args|
            system("xscreensaver-command --lock")
      end
    })

I start my xscreensaver in the .xsession file:

    /usr/bin/xscreensaver -nosplash &

… before launching wmii.