change KeyboardInterrupt to 'enter'

Question

I have the following code:

import time

def run_indefinitely():
    while True:
        # code to run indefinitely goes here
        print("Running indefinitely...")
        time.sleep(1)  

try:
    
        # Run the code indefinitely until Enter key is pressed
        run_indefinitely()            

except KeyboardInterrupt:
    print("Loop interrupted by user")

Is there a way to break out of the while loop by hitting 'enter' instead of ctrl+C ?

Answer 1

This is surprisingly tricky to do in Python. The technique involves spawning a worker thread to interrupt us later.

Using python-readchar:

import os
import signal
import sys
import time
from threading import Timer

from readchar import readkey  # pip install readchar

def wait_for(key, timeout):
    """wait `timeout` seconds for user to press `key`"""
    pid = os.getpid()
    sig = signal.CTRL_C_EVENT if os.name == "nt" else signal.SIGINT
    timer = Timer(timeout, lambda: os.kill(pid, sig))
    timer.start()
    while True:
        k = readkey()
        print(f"received {k!r}")
        if k == key:
            timer.cancel()  # cancel the timer
            print("breaking")
            break

def run_indefinitely():
    while True:
        print("Running indefinitely...")
        try:
            wait_for(key="\n", timeout=1)
        except KeyboardInterrupt:
            continue
        else:
            break

run_indefinitely()
print("Loop interrupted by user")

Using pynput:

import os
import signal
import time

from pynput import keyboard  # pip install pynput

pid = os.getpid()

def on_press(key):
    if key is keyboard.Key["enter"]:
        sig = signal.CTRL_C_EVENT if os.name == "nt" else signal.SIGINT
        os.kill(pid, sig)

with keyboard.Listener(on_press=on_press) as k:
    try:
        for i in range(10):
            print("Running indefinitely...")
            time.sleep(1)
    except KeyboardInterrupt:
        pass

print("Loop interrupted by user")