How can I catch a system suspend event in Python?

Question

I'm using ubuntu 12.04. Is there a way to catch a suspend event in Python, i.e. if the laptop is going to suspend, do this...? The same question for catching shutdown event.

Answer 1

i think simplest method would be to use DBUS python interface and listen for 'AboutToSleep' and/or 'Sleeping' event on 'org.freedesktop.UPower' interface

Answer 2

If some one stumbles on the same problem, here's the code:

#!/usr/bin/env python

import dbus      # for dbus communication (obviously)
import gobject   # main loop
from dbus.mainloop.glib import DBusGMainLoop # integration into the main loop

def handle_resume_callback():
    print "System just resumed from hibernate or suspend"

def handle_suspend_callback():
    print "System about to hibernate or suspend"

DBusGMainLoop(set_as_default=True) # integrate into main loob
bus = dbus.SystemBus()             # connect to dbus system wide
bus.add_signal_receiver(           # defince the signal to listen to
    handle_resume_callback,            # name of callback function
    'Resuming',                        # singal name
    'org.freedesktop.UPower',          # interface
    'org.freedesktop.UPower'           # bus name
)

bus.add_signal_receiver(           # defince the signal to listen to
    handle_suspend_callback,            # name of callback function
    'Sleeping',                        # singal name
    'org.freedesktop.UPower',          # interface
    'org.freedesktop.UPower'           # bus name
)

loop = gobject.MainLoop()          # define mainloop
loop.run()                         # run main loop

Answer 3

You can extend this code, it listens for events from acpid, try to just print the string it receives and generate the event you want and see what the string looks like.

s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
s.connect("/var/run/acpid.socket")
print "Connected to acpid"
while 1:
    for event in s.recv(4096).split('\n'):
        event=event.split(' ')
        if len(event)<2: continue
        print event
        if event[0]=='ac_adapter':
            if event[3]=='00000001': #plugged
                plugged() #Power plugged event
            else: #unplugged
                unplugged() #Power unplugged event
        elif event[0]=='button/power':
            power_button() #Power button pressed
        elif event[0]=='button/lid':
            if event[2]=='open':
                lid_open() #Laptop lid opened
            elif event[2]=='close':
                lid_close() #Laptop lid closed