Get the stdout of a sub process in an extension ?

[Thomas Bouffon <thomas bouffon gmail com>]

Hello,
I'm writing an extension which gives me the time for the next bus close to my office in the status tray. 
I successfully created and displayed a button close to what the clock is (I want to start an app when clicking on it).
My problem is to fill the label with the next bus time. I already have an executable which gives the time in stdout.

Maybe I am not doing things the right way and shoud use Dbus instead ? or are there any other options to put things in the status tray ?

Thank you very much,
Thomas