Windows global hotkeys in a thread

globalkeys.py

# After "Tim Golden's Python Stuff" code
# http://timgolden.me.uk/python/win32_how_do_i/catch_system_wide_hotkeys.html

#
# After a post to c.l.py by Richie Hindle:
# http://groups.google.com/groups?th=80e876b88fabf6c9
#
import os
import sys
import threading
import ctypes
from ctypes import wintypes
import win32con


byref = ctypes.byref
user32 = ctypes.windll.user32

HOTKEYS = {
  1 : (win32con.VK_F1, None),
}

def handle_default(key):
    print "* handle key", key
    user32.PostQuitMessage (0)

HOTKEY_ACTIONS = {
  1 : handle_default,
}

class GlobalKeys(threading.Thread):

    def __init__(self, hotkeys=HOTKEYS, actions=HOTKEY_ACTIONS):
        """HOTKEYS: dict{ id: (key, modifier) }
           HOTKEY_ACTIONS: dict{ id: callback }"""
        super(GlobalKeys, self).__init__()
        self.HOTKEYS = hotkeys
        self.HOTKEY_ACTIONS = actions
        self.loop = True
        self.HOTKEYS[0] = (None, None)
        self.HOTKEY_ACTIONS[0] = handle_default
 
    def run(self):
        #
        # RegisterHotKey takes:
        #  Window handle for WM_HOTKEY messages (None = this thread)
        #  arbitrary id unique within the thread
        #  modifiers (MOD_SHIFT, MOD_ALT, MOD_CONTROL, MOD_WIN)
        #  VK code (either ord ('x') or one of win32con.VK_*)
        #
        for id, (vk, modifiers) in self.HOTKEYS.items ():
          #print "Registering id", id, "for key", vk
          if not user32.RegisterHotKey (None, id, modifiers, vk):
            print "Unable to register hotkey id", id

        #
        # Home-grown Windows message loop: does
        #  just enough to handle the WM_HOTKEY
        #  messages and pass everything else along.
        #
        try:
            msg = wintypes.MSG() 
            while user32.GetMessageA (byref (msg), None, 0, 0) != 0:
                if msg.message == win32con.WM_HOTKEY:
                    action_to_take = self.HOTKEY_ACTIONS.get (msg.wParam)
                    if action_to_take:
                        action_to_take(msg.wParam)

                user32.TranslateMessage (byref (msg))
                user32.DispatchMessageA (byref (msg))
                if not self.loop:
                    break

        finally:
          for id in self.HOTKEYS.keys ():
            user32.UnregisterHotKey (None, id)

    def stop(self):
        self.loop = False
        user32.keybd_event(None, 0, 0, 0)
        user32.keybd_event(None, 0, 0x0002, 0)

if __name__=="__main__":
    gk = GlobalKeys()
    print "start"
    gk.start()
    print "running"
    gk.join()
    print "end"