Python: cross-platform code to read keypress with a timeout. Good for "press any key to continue" with an expiration timer.

read_keypress_with_timeout.py

import os
import time
from typing import Optional

if os.name == "posix":
    import select
    import sys
    import termios
    import tty

    def read_keypress_with_timeout(timeout: float) -> Optional[str]:
        end_time = time.time() + timeout
        stdin_fileno = sys.stdin.fileno()
        saved_tcattr = termios.tcgetattr(stdin_fileno)
        try:
            tty.setcbreak(stdin_fileno)
            while time.time() <= end_time:
                if select.select((sys.stdin,), (), (), 0.1)[0]:
                    return sys.stdin.read(1)
        finally:
            termios.tcsetattr(stdin_fileno, termios.TCSAFLUSH, saved_tcattr)
elif os.name == "nt":
    try:
        import msvcrt

        def read_keypress_with_timeout(timeout: float) -> Optional[str]:
            end_time = time.time() + timeout
            while time.time() <= end_time:
                if msvcrt.kbhit():
                    return msvcrt.getwch()
    except ImportError:
        def read_keypress_with_timeout(timeout: float) -> None:
            time.sleep(timeout)
else:
    def read_keypress_with_timeout(timeout: float) -> None:
        time.sleep(timeout)