A small example for python-xlib that works of events in a semi-blocking way using select.

python_xlib_select_spike.py

#!/usr/bin/python3

import sys
import os
from Xlib import X, display, Xutil
import select

# http://python-xlib.sourceforge.net/doc/html/python-xlib_11.html

# Application window (only one)
class Window(object):
    def __init__(self):
        print("Runs until escape is pressed.")
        self.d = display.Display()
        s = self.d.screen()
        self.s = s

        self.window = s.root.create_window(
            0, 0, s.width_in_pixels, s.height_in_pixels,
            2, s.root_depth,
            X.InputOutput, X.CopyFromParent,
            background_pixel = s.white_pixel,
            event_mask = (X.KeyPressMask | X.KeyReleaseMask),
            colormap = X.CopyFromParent,
        )

        self.gc = self.window.create_gc(
            foreground = s.black_pixel,
            background = s.white_pixel,
            )

        self.WM_DELETE_WINDOW = self.d.intern_atom('WM_DELETE_WINDOW')
        self.window.map() # show window


    # Main loop, handling events
    def loop(self):
        self.loop_cond = True
        timeout=5

        while self.loop_cond:
            # handle all available events
            i = self.d.pending_events()
            while i > 0:
                event = self.d.next_event()
                self.handle_event(event)
                i = i - 1

             # Wait for display to send something, or a timeout of one second
            readable, w, e = select.select([self.d], [], [], timeout)

            # if no files are ready to be read, it's an timeout
            if not readable:
                self.handle_timeout()

    def handle_timeout(self):
        print("Timeout")

    def handle_event(self, e):
        if e.type == X.KeyRelease or e.type == X.KeyPress:
            keycode = e.detail
            print(keycode+" was pressed/released")
            if (keycode==9):
                self.loop_cond=False

if __name__ == "__main__":
    window = Window().loop()