First you'll need a way to schedule tasks. If you're not familiar
with cron, and you're using Ubuntu/GNOME then
sudo apt-get install gnome-schedule. Then you can
open Scheduled Tasks from the System >>
Preferences menu and use the GUI to set a specific time for a
command to run.
The simplest way to schedule a time for Empathy to connect and
disconnect is to just schedule jobs to start and stop the program
(just use the commands empathy and killall
empathy). The problem is that if we kill Empathy without
logging out then you'll still appear signed in for a few minutes
until Google discovers that you've timed out.
To get around that problem we can use D-Bus to send a signal to Empathy's
backend that asks it to disconnect. There are lots of ways to
do this including with dbus-send from the command
line, but since I'm more familiar with Python I used that.
Instead of configuring your sign-off task to call killall
empathy, save the following script somewhere (e.g.
~/empathy_signout.py) and then schedule your task to
call that (python ~/empathy_signout.py). Replace
the string EXAMPLE in the fourth line with
your Google Talk account name before you save the file.
#!/usr/bin/env python
# Disconnect Empathy from Google Talk and kill the program.
# Replace EXAMPLE below with your account name (whatever is before @gmail.com)
google_acct_name = 'EXAMPLE'
import os
try:
import dbus
except ImportError:
exit('You need the Python dbus bindings,'
' type "sudo apt-get install python-dbus".')
wkname = ('org.freedesktop.Telepathy.Connection.gabble.jabber.' +
google_acct_name + '_40gmail_2ecom_2fTelepathy')
pathname = '/' + wkname.replace('.', '/')
bus = dbus.SessionBus()
conn_obj = bus.get_object(wkname, pathname)
conn_obj.Disconnect(dbus_interface='org.freedesktop.Telepathy.Connection')
os.system('killall empathy')
This script could be tweaked to avoid the hacky guess of the account name path component, or to sign on also (If quitting the program is a problem). Take a look at the ConnectionManager interface in the Telepathy D-Bus docs if this stuff doesn't frighten you.