Python: wait for input(), else continue after x seconds

waitForInput.py

# from threading import Thread

# class Input:
#     _response = None # internal use only

#     @classmethod
#     def timeout(cls, message, timeout):
#         cls._response = None
#         print('You have {0} seconds to answer'.format(timeout))
#         thread = Thread(target=cls.do_input, args=(message,))
#         thread.start()
#         # wait for a response
#         thread.join(timeout)
#         # closing input after timeout
#         if cls._response is None:
#             print('\nTimes up. Press enter to continue')
#             thread.join()
#             # clear response from enter key
#             cls._response = None
#         return cls._response

#     @classmethod
#     def do_input(cls, message):
#         cls._response = input(message)

# def main():
#     r = Input.timeout('Type anything >> ', 2)
#     print(r)
#     r = Input.timeout('Type anything >> ', 3)
#     print(r)


# main()

import threading
import queue
import time


def get_input(message, channel):
    response = input(message)
    channel.put(response)


def input_with_timeout(message, timeout):
    channel = queue.Queue()
    message = message + " [{} sec timeout] ".format(timeout)
    thread = threading.Thread(target=get_input, args=(message, channel))
    # by setting this as a daemon thread, python won't wait for it to complete
    thread.daemon = True
    thread.start()

    try:
        response = channel.get(True, timeout)
        return response
    except queue.Empty:
        pass
    return None


if __name__ == "__main__":
    a = input_with_timeout("Commands:", 5)
    time.sleep(3)
    print(a)

Well good

The problem is what happens when there is no input but you want to receive another input after this. Then the thread that's waiting for input will "eat" the input that someone else is waiting for. The solution that was pointed out to me is to use select.select() to wait until there is input. If there isn't, it will stop waiting after a timeout. If there is input, then it will return a list of objects from which input can be read, and only then you read the input. Here:

def _wait_for_enter(channel: queue.Queue, timeout: int = None):
    (rlist, wlist, xlist) = select([stdin], [], [], timeout)

    if len(rlist):
        line = stdin.readline()
        channel.put(line)

All this does is wait for a line to be entered, then return that line. If no line is entered, it won't try to read the input. This allows the next call to input() to actually work.