Ubuntu – AppIndicator vala library

Application indicators are based on KStatusNotifierItem.

I'm not too familiar with it but here's a tutorial on how to get started. That's all you really need to get it to work, the app icon and it's menus should then render properly regardless of which desktop it's in.

Use g_timeout_add_seconds() from GLib to define a function that is called at regular intervals and in this function check the port and call indicator.set_status(...) is needed.