xlib.py

from Xlib.display import Display
import Xlib
from Xlib import X, XK
import Xlib.XK
import sys
import signal 
import Queue

display = None
root = None
queue = []
isBlock = False

def handle_event(aEvent):
    global queue, isBlock
    keysym = display.keycode_to_keysym(aEvent.detail, 0)
    if aEvent.type == X.KeyReleaseMask:
        if len(queue) == 6:
            queue = queue[1:6]

        queue.append(lookup_keysym(keysym))
        st = "".join([str(x) for x in queue])
        if "hello" in st:
            if isBlock == False:
                queue = []
                block()
            else:
                queue = []
                unBlock()

def lookup_keysym(keysym):
    for name in dir(XK):
        if name[:3] == "XK_" and getattr(XK, name) == keysym:
            return name[3:]
    return "[%d]" % keysym

def block():
    global isBlock, root
    isBlock = True
    root.grab_pointer(True, X.ButtonPressMask | X.ButtonReleaseMask, X.GrabModeAsync, X.GrabModeAsync, 0, 0, X.CurrentTime)
    root.grab_key(Xlib.X.AnyKey, X.AnyModifier, True,X.GrabModeSync, X.GrabModeSync)
    while 1:
        event = display.next_event()
        print "You can't do anything"
        #if i dont call this, the whole thing freezes
        display.allow_events(X.AsyncKeyboard, X.CurrentTime)
        display.allow_events(X.AsyncPointer, X.CurrentTime)
        handle_event(event)

def unBlock():
    global isBlock, root, display
    isBlock = False
    display.ungrab_pointer(X.CurrentTime)
    root.grab_key(Xlib.X.AnyKey, X.AnyModifier, True,X.GrabModeSync, X.GrabModeSync)
    while 1:
        event = display.next_event()
        print "Now, you can do"
        #if i dont call this, the whole thing freezes
        display.allow_events(X.ReplayKeyboard, X.CurrentTime)
        #display.allow_events(X.ReplayPointer, X.CurrentTime)
        handle_event(event)

def main():
    # current display
    global display,root,isBlock
    display = Display()
    root = display.screen().root

    # we tell the X server we want to catch keyPress event
    root.change_attributes(event_mask = X.KeyPressMask | X.KeyReleaseMask)
    if isBlock == False:
        block()

if __name__ == '__main__':
    main()