Keyboard input with timeout?

Question

How would you prompt the user for some input but timing out after N seconds?

Google is pointing to a mail thread about it at http://mail.python.org/pipermail/python-list/2006-January/533215.html but it seems not to work. The statement in which the timeout happens, no matter whether it is a sys.input.readline or timer.sleep(), I always get:

<type 'exceptions.TypeError'>: [raw_]input expected at most 1 arguments, got 2

which somehow the except fails to catch.

Answer 1

Using a select call is shorter, and should be much more portable

import sys, select

print "You have ten seconds to answer!"

i, o, e = select.select( [sys.stdin], [], [], 10 )

if (i):
  print "You said", sys.stdin.readline().strip()
else:
  print "You said nothing!"

Answer 2

The example you have linked to is wrong and the exception is actually occuring when calling alarm handler instead of when read blocks. Better try this:

import signal
TIMEOUT = 5 # number of seconds your want for timeout

def interrupted(signum, frame):
    "called when read times out"
    print 'interrupted!'
signal.signal(signal.SIGALRM, interrupted)

def input():
    try:
            print 'You have 5 seconds to type in your stuff...'
            foo = raw_input()
            return foo
    except:
            # timeout
            return

# set alarm
signal.alarm(TIMEOUT)
s = input()
# disable the alarm after success
signal.alarm(0)
print 'You typed', s

Answer 3

Not a Python solution, but...

I ran in to this problem with a script running under CentOS (Linux), and what worked for my situation was just running the Bash "read -t" command in a subprocess. Brutal disgusting hack, I know, but I feel guilty enough about how well it worked that I wanted to share it with everyone here.

import subprocess
subprocess.call('read -t 30', shell=True)

All I needed was something that waited for 30 seconds unless the ENTER key was pressed. This worked great.

Answer 4

And here's one that works on Windows

I haven't been able to get any of these examples to work on Windows so I've merged some different StackOverflow answers to get the following:

import threading, msvcrt
import sys

def readInput(caption, default, timeout = 5):
    class KeyboardThread(threading.Thread):
        def run(self):
            self.timedout = False
            self.input = ''
            while True:
                if msvcrt.kbhit():
                    chr = msvcrt.getche()
                    if ord(chr) == 13:
                        break
                    elif ord(chr) >= 32:
                        self.input += chr
                if len(self.input) == 0 and self.timedout:
                    break    


    sys.stdout.write('%s(%s):'%(caption, default));
    result = default
    it = KeyboardThread()
    it.start()
    it.join(timeout)
    it.timedout = True
    if len(it.input) > 0:
        # wait for rest of input
        it.join()
        result = it.input
    print ''  # needed to move to next line
    return result

# and some examples of usage
ans = readInput('Please type a name', 'john') 
print 'The name is %s' % ans
ans = readInput('Please enter a number', 10 ) 
print 'The number is %s' % ans 

Answer 5

Paul's answer did not quite work. Modified code below which works for me on

• windows 7 x64

• vanilla CMD shell (eg, not git-bash or other non-M$ shell)

  -- nothing msvcrt works in git-bash it appears.

• python 3.6

(I'm posting a new answer, because editing Paul's answer directly would change it from python 2.x-->3.x, which seems too much for an edit (py2 is still in use)

import sys, time, msvcrt

def readInput( caption, default, timeout = 5):

    start_time = time.time()
    sys.stdout.write('%s(%s):'%(caption, default))
    sys.stdout.flush()
    input = ''
    while True:
        if msvcrt.kbhit():
            byte_arr = msvcrt.getche()
            if ord(byte_arr) == 13: # enter_key
                break
            elif ord(byte_arr) >= 32: #space_char
                input += "".join(map(chr,byte_arr))
        if len(input) == 0 and (time.time() - start_time) > timeout:
            print("timing out, using default value.")
            break

    print('')  # needed to move to next line
    if len(input) > 0:
        return input
    else:
        return default

# and some examples of usage
ans = readInput('Please type a name', 'john') 
print( 'The name is %s' % ans)
ans = readInput('Please enter a number', 10 ) 
print( 'The number is %s' % ans) 

Answer 6

Following code worked for me.

I used two threads one to get the raw_Input and another to wait for a specific time. If any of the thread exits, both the thread is terminated and returned.

def _input(msg, q):
    ra = raw_input(msg)
    if ra:
        q.put(ra)
    else:
        q.put("None")
    return

def _slp(tm, q):
    time.sleep(tm)
    q.put("Timeout")
    return

def wait_for_input(msg="Press Enter to continue", time=10):
    q = Queue.Queue()
    th = threading.Thread(target=_input, args=(msg, q,))
    tt = threading.Thread(target=_slp, args=(time, q,))

    th.start()
    tt.start()
    ret = None
    while True:
        ret = q.get()
        if ret:
            th._Thread__stop()
            tt._Thread__stop()
            return ret
    return ret

print time.ctime()    
t= wait_for_input()
print "\nResponse :",t 
print time.ctime()

Answer 7

I spent a good twenty minutes or so on this, so I thought it was worth a shot to put this up here. It is directly building off of user137673's answer, though. I found it most useful to do something like this:

#! /usr/bin/env python

import signal

timeout = None

def main():
    inp = stdinWait("You have 5 seconds to type text and press <Enter>... ", "[no text]", 5, "Aw man! You ran out of time!!")
    if not timeout:
        print "You entered", inp
    else:
        print "You didn't enter anything because I'm on a tight schedule!"

def stdinWait(text, default, time, timeoutDisplay = None, **kwargs):
    signal.signal(signal.SIGALRM, interrupt)
    signal.alarm(time) # sets timeout
    global timeout
    try:
        inp = raw_input(text)
        signal.alarm(0)
        timeout = False
    except (KeyboardInterrupt):
        printInterrupt = kwargs.get("printInterrupt", True)
        if printInterrupt:
            print "Keyboard interrupt"
        timeout = True # Do this so you don't mistakenly get input when there is none
        inp = default
    except:
        timeout = True
        if not timeoutDisplay is None:
            print timeoutDisplay
        signal.alarm(0)
        inp = default
    return inp

def interrupt(signum, frame):
    raise Exception("")

if __name__ == "__main__":
    main()

Answer 8

Here is a portable and simple Python 3 solution using threads. This is the only one that worked for me while being cross-platform.

Other things I tried all had problems:

• Using signal.SIGALRM: not working on Windows
• Using select call: not working on Windows
• Using force-terminate of a process (instead of thread): stdin cannot be used in new process (stdin is auto-closed)
• Redirection stdin to StringIO and writing directly to stdin: will still write to previous stdin if input() has already been called (see https://stackoverflow.com/a/15055639/9624704)

    from threading import Thread
    class myClass:
        _input = None

        def __init__(self):
            get_input_thread = Thread(target=self.get_input)
            get_input_thread.daemon = True  # Otherwise the thread won't be terminated when the main program terminates.
            get_input_thread.start()
            get_input_thread.join(timeout=20)

            if myClass._input is None:
                print("No input was given within 20 seconds")
            else:
                print("Input given was: {}".format(myClass._input))


        @classmethod
        def get_input(cls):
            cls._input = input("")
            return

Answer 9

my cross platform solution

def input_process(stdin_fd, sq, str):
    sys.stdin = os.fdopen(stdin_fd)
    try:
        inp = input (str)
        sq.put (True)
    except:
        sq.put (False)

def input_in_time (str, max_time_sec):
    sq = multiprocessing.Queue()
    p = multiprocessing.Process(target=input_process, args=( sys.stdin.fileno(), sq, str))
    p.start()
    t = time.time()
    inp = False
    while True:
        if not sq.empty():
            inp = sq.get()
            break
        if time.time() - t > max_time_sec:
            break
    p.terminate()
    sys.stdin = os.fdopen( sys.stdin.fileno() )
    return inp

Answer 10

if you dont care how it works, just
pip install inputimeout
and

from inputimeout import inputimeout, TimeoutOccurred

if __name__ == "__main__":
    try:
        c = inputimeout(prompt='hello\n', timeout=3)
    except TimeoutOccurred:
        c = 'timeout'
    print(c)

so easy
https://pypi.org/project/inputimeout/

Answer 11

Analogous to Locane's for windows:

import subprocess  
subprocess.call('timeout /T 30')

Answer 12

For Linux, I would prefer the select version by @Pontus. Here just a python3 function works like read in shell:

import sys, select

def timeout_input(prompt, timeout=3, default=""):
    print(prompt, end=': ', flush=True)
    inputs, outputs, errors = select.select([sys.stdin], [], [], timeout)
    print()
    return (0, sys.stdin.readline().strip()) if inputs else (-1, default)

Run

In [29]: timeout_input("Continue? (Y/n)", 3, "y")                                                                                                                                                                  
Continue? (Y/n): 
Out[29]: (-1, 'y')

In [30]: timeout_input("Continue? (Y/n)", 3, "y")                                                                                                                                                                  
Continue? (Y/n): n

Out[30]: (0, 'n')

And a yes_or_no function

In [33]: yes_or_no_3 = lambda prompt: 'n' not in timeout_input(prompt + "? (Y/n)", 3, default="y")[1].lower()                                                                                                      

In [34]: yes_or_no_3("Continue")                                                                                                                                                                                   
Continue? (Y/n): 
Out[34]: True

In [35]: yes_or_no_3("Continue")                                                                                                                                                                                   
Continue? (Y/n): no

Out[35]: False

Answer 13

Modified iperov answer that works for me (python3 win10 2019-12-09)

changes to iperov:

• replace str with sstr as str is a function in python

• add imports

• add sleep to lower cpu usage of the while loop (?)

• add if name=='main': #required by multiprocessing on windows

  import sys, os, multiprocessing, time

  def input_process(stdin_fd, sq, sstr):
      sys.stdin = os.fdopen(stdin_fd)
      try:
          inp = input(sstr)
          sq.put(True)
      except:
          sq.put(False)
  
  def input_in_time(sstr, max_time_sec):
      sq = multiprocessing.Queue()
      p = multiprocessing.Process(target=input_process, args=( sys.stdin.fileno(), sq, sstr))
      p.start()
      t = time.time()
      inp = False
      while True:
  
          if not sq.empty():
              inp = sq.get()
              break
          if time.time() - t > max_time_sec:
              break
  
          tleft=int( (t+max_time_sec)-time.time())
          if tleft<max_time_sec-1 and tleft>0:
              print('\n  ...time left '+str(tleft)+'s\ncommand:')
  
          time.sleep(2)
  
      p.terminate()
      sys.stdin = os.fdopen( sys.stdin.fileno() )
      return inp
  
  if __name__=='__main__':
      input_in_time("command:", 17)
  

Answer 14

This is the way I approached this problem. I haven't tested it thoroughly, and I'm not sure it doesn't have some important problems, but considering other solutions are far from perfect as well, I decided to share:

import sys
import subprocess


def switch():
    if len(sys.argv) == 1:
        main()
    elif sys.argv[1] == "inp":
        print(input(''))
    else:
        print("Wrong arguments:", sys.argv[1:])


def main():
    passw = input_timed('You have 10 seconds to enter password:', timeout=10)
    if passw is None:
        print("Time's out! You explode!")
    elif passw == "PasswordShmashword":
        print("H-h-how did you know you h-h-hacker")
    else:
        print("I spare your life because you at least tried")


def input_timed(*args, timeout, **kwargs):
    """
    Print a message and await user input - return None if timedout
    :param args: positional arguments passed to print()
    :param timeout: number of seconds to wait before returning None
    :param kwargs: keyword arguments passed to print()
    :return: user input or None if timed out
    """
    print(*args, **kwargs)
    try:
        out: bytes = subprocess.run(["python", sys.argv[0], "inp"], capture_output=True, timeout=timeout).stdout
    except subprocess.TimeoutExpired:
        return None
    return out.decode('utf8').splitlines()[0]


switch()

Answer 15

It's been years already, but just incase someone bumps into this like I did recently trying to solve this sort of problem, there is an easy and faster way of achieving this using the func-timeout package. It has to be installed before use for most IDEs; you can install it via pip. The above link is self explanatory, but I will give an example on how I implemented it.

from func_timeout import FunctionTimedOut, func_timeout

try:
   ans = func_timeout(5, lambda: int(input('What is the sum of 2 and 3?\n')))
   print(ans)
except FunctionTimedOut:
   print(5)

func_timeout returns the value of the method in its argument, the question() function in this case. It also allows for other arguments that are needed for the function (see documentation). If the set time elapses (5 secs here) it raises a TimedOutException and runs the code in the except block.

Answer 16

from threading import Thread
import time


def get_input():
    while True:
        print(input('> '))


t1 = Thread(target=get_input)
t1.setDaemon(True)
t1.start()
time.sleep(3)
print('program exceeds')

Well just simply set a new Daemon thread, and set a sleep time that whatever you want for timeout. I think that is easy to catch up XD

Answer 17

I am using a external tool inputimeout . Source code is available at github. I know it is a external tool but it is simple and quite handy. After installing the tool use this code:

from inputimeout import inputimeout, TimeoutOccurred
try:
    something = inputimeout(prompt='>>', timeout=5)
except TimeoutOccurred:
    something = 'No input.'
print(something)

Answer 18

Solution inspired by iperov's answer which is hopefully a bit cleaner:

import multiprocessing
import sys

def input_with_timeout(prompt, timeout=None):
    """Requests the user to enter a code at the command line."""
    queue = multiprocessing.Queue()
    process = multiprocessing.Process(
        _input_with_timeout_process, args=(sys.stdin.fileno(), queue, prompt),
    )
    process.start()
    try:
        process.join(timeout)
        if process.is_alive():
            raise ValueError("Timed out waiting for input.")
        return queue.get()
    finally:
        process.terminate()


def _input_with_timeout_process(stdin_file_descriptor, queue, prompt):
    sys.stdin = os.fdopen(stdin_file_descriptor)
    queue.put(input(prompt))

Answer 19

This is a Python 3.8+ (although it can be adapted to Python 3.6+) cross-platform approach that only uses threading (so no multiprocessing or calls to shell utilities). It is intended for running scripts from the command-line and isn't very suited for dynamical use.

You can wrap the builtin input function as follows. In this case I'm redefining the built-in name input as the wrapper, since this implementation requires all calls to input to be routed through this. (Disclaimer: that's why it's probably not a very good idea, just a different one, for fun.)

import atexit
import builtins
import queue
import threading


def _make_input_func():
    prompt_queue = queue.Queue(maxsize=1)
    input_queue = queue.Queue(maxsize=1)

    def get_input():
        while (prompt := prompt_queue.get()) != GeneratorExit:
            inp = builtins.input(prompt)
            input_queue.put(inp)
            prompt_queue.task_done()

    input_thread = threading.Thread(target=get_input, daemon=True)

    last_call_timed_out = False

    def input_func(prompt=None, timeout=None):
        """Mimics :function:`builtins.input`, with an optional timeout

        :param prompt: string to pass to builtins.input
        :param timeout: how long to wait for input in seconds; None means indefinitely

        :return: the received input if not timed out, otherwise None
        """
        nonlocal last_call_timed_out

        if not last_call_timed_out:
            prompt_queue.put(prompt, block=False)
        else:
            print(prompt, end='', flush=True)

        try:
            result = input_queue.get(timeout=timeout)
            last_call_timed_out = False
            return result
        except queue.Empty:
            print(flush=True) # optional: end prompt line if no input received
            last_call_timed_out = True
            return None


    input_thread.start()
    return input_func


input = _make_input_func()
del _make_input_func

(I've defined the setup in the one-use-only _make_input_func to hide input's "static" variables in its closure, in order to avoid polluting the global namespace.)

The idea here is to make a separate thread which handles any and all calls to builtins.input, and make the input wrapper manage the timeout. Since a call to builtins.input always blocks until there is input, when the timeout is over, the special thread is still waiting for input, but the input wrapper returns (with None). At the next call, if the last call timed out, it doesn't need to call builtins.input again (since the input thread has already been waiting for input), it just prints the prompt, and then waits for said thread to return some input, as always.

Having defined the above, try running the following script:

import time

if __name__ == '__main__':
    timeout = 2
    start_t = time.monotonic()
    if (inp := input(f"Enter something (you have {timeout} seconds): ", timeout)) is not None:
        print("Received some input:", repr(inp))
    else:
        end_t = time.monotonic()
        print(f"Timed out after {end_t - start_t} seconds")

    inp = input("Enter something else (I'll wait this time): ")
    print("Received some input:", repr(inp))
    
    input(f"Last chance to say something (you have {timeout} seconds): ", timeout)

Answer 20

Some of the answers require to press the Enter key when the timeout occurs to continue running your code. Others seem to be convoluted, and to boot, still require to press the Enter key after timeout.

I found the answer in another thread, which works beautifully, but there's a caveat that I found. I decided to place my code in a class for portability.

Note

I had to use keyboard to inject the Enter key press, since I had another input() statement in my code. For some reason, the subsequent input() statement wouldn't appear unless I pressed the Enter key.

import threading
import keyboard    # https://github.com/boppreh/keyboard

class Utilities:

    # Class variable
    response = None

    @classmethod
    def user_input(cls, timeout):

        def question():
            cls.response = input("Enter something: ")

        t = threading.Thread(target=question)
        # Daemon property allows the target function to terminate after timeout
        t.daemon = True    
        t.start()
        t.join(timeout)

        if cls.response:
            # Do something
        else:
            # Do something else
            # Optional.  Use if you have other input() statements in your code
            keyboard.send("enter")

Usage

Utilities.user_input(3)

This was made with Python 3.8.3 on Windows 10.

Answer 21

Here is one more that python 3.8+ on linux that includes a yes_no answer with default return on timeout

import signal
def alarm_handler(signum, frame):
    raise TimeoutError
def input_with_timeout(prompt, timeout=30):
    """ get input with timeout

    :param prompt: the prompt to print
    :param timeout: timeout in seconds, or None to disable

    :returns: the input
    :raises: TimeoutError if times out
    """
    # set signal handler
    if timeout is not None:
        signal.signal(signal.SIGALRM, alarm_handler)
        signal.alarm(timeout) # produce SIGALRM in `timeout` seconds
    try:
        return input(prompt)
    except TimeoutError as to:
        raise to
    finally:
        if timeout is not None:
            signal.alarm(0) # cancel alarm

def yes_or_no(question, default='y', timeout=None):
    """ Get y/n answer with default choice and optional timeout

    :param question: prompt
    :param default: the default choice, i.e. 'y' or 'n'
    :param timeout: the timeout in seconds, default is None

    :returns: True or False
    """
    if default is not None and (default!='y' and default!='n'):
        log.error(f'bad option for default: {default}')
        quit(1)
    y='Y' if default=='y' else 'y'
    n='N' if default=='n' else 'n'
    while "the answer is invalid":
        try:
            to_str='' if timeout is None else f'(Timeout {default} in {timeout}s)'
            reply = str(input_with_timeout(f'{question} {to_str} ({y}/{n}): ',timeout=timeout)).lower().strip()
        except TimeoutError:
            log.warning(f'timeout expired, returning default={default} answer')
            reply=''
        if len(reply)==0:
            return True if default=='y' else False
        elif reply[0] == 'y':
            return True
        if reply[0] == 'n':
            return False

Example of use in code

if yes_or_no(f'model {latest_model_folder} exists, start from it?', timeout=TIMEOUT):
     log.info(f'initializing model from {latest_model_folder}')
     model = load_model(latest_model_folder)
else:
     log.info('creating new empty model')
     model = create_model()

Answer 22

there is a library for this now from MIT.

pip install inputimeout

https://pypi.org/project/inputimeout/

Answer 23

A late answer :)

I would do something like this:

from time import sleep

print('Please provide input in 20 seconds! (Hit Ctrl-C to start)')
try:
    for i in range(0,20):
        sleep(1) # could use a backward counter to be preeety :)
    print('No input is given.')
except KeyboardInterrupt:
    raw_input('Input x:')
    print('You, you! You know something.')

I know this is not the same but many real life problem could be solved this way. (I usually need timeout for user input when I want something to continue running if the user not there at the moment.)

Hope this at least partially helps. (If anyone reads it anyway :) )