[python] Key Listeners in python?

Is there a way to do key listeners in python without a huge bloated module such as pygame?

An example would be, when I pressed the a key it would print to the console

The a key was pressed!

It should also listen for the arrow keys/spacebar/shift key.

Here's how can do it on Windows:

"""

    Display series of numbers in infinite loop
    Listen to key "s" to stop
    Only works on Windows because listening to keys
    is platform dependent

"""

# msvcrt is a windows specific native module
import msvcrt
import time

# asks whether a key has been acquired
def kbfunc():
    #this is boolean for whether the keyboard has bene hit
    x = msvcrt.kbhit()
    if x:
        #getch acquires the character encoded in binary ASCII
        ret = msvcrt.getch()
    else:
        ret = False
    return ret

#begin the counter
number = 1

#infinite loop
while True:

    #acquire the keyboard hit if exists
    x = kbfunc() 

    #if we got a keyboard hit
    if x != False and x.decode() == 's':
        #we got the key!
        #because x is a binary, we need to decode to string
        #use the decode() which is part of the binary object
        #by default, decodes via utf8
        #concatenation auto adds a space in between
        print ("STOPPING, KEY:", x.decode())
        #break loop
        break
    else:
        #prints the number
        print (number)
        #increment, there's no ++ in python
        number += 1
        #wait half a second
        time.sleep(0.5)

I was searching for a simple solution without window focus. Jayk's answer, pynput, works perfect for me. Here is the example how I use it.

from pynput import keyboard

def on_press(key):
    if key == keyboard.Key.esc:
        return False  # stop listener
    try:
        k = key.char  # single-char keys
    except:
        k = key.name  # other keys
    if k in ['1', '2', 'left', 'right']:  # keys of interest
        # self.keys.append(k)  # store it in global-like variable
        print('Key pressed: ' + k)
        return False  # stop listener; remove this if want more keys

listener = keyboard.Listener(on_press=on_press)
listener.start()  # start to listen on a separate thread
listener.join()  # remove if main thread is polling self.keys

keyboard

• sudo pip install keyboard
• https://github.com/boppreh/keyboard

Take full control of your keyboard with this small Python library. Hook global events, register hotkeys, simulate key presses and much more.

Global event hook on all keyboards (captures keys regardless of focus). Listen and sends keyboard events. Works with Windows and Linux (requires sudo), with experimental OS X support (thanks @glitchassassin!). Pure Python, no C modules to be compiled. Zero dependencies. Trivial to install and deploy, just copy the files. Python 2 and 3. Complex hotkey support (e.g. Ctrl+Shift+M, Ctrl+Space) with controllable timeout. Includes high level API (e.g. record and play, add_abbreviation). Maps keys as they actually are in your layout, with full internationalization support (e.g. Ctrl+ç). Events automatically captured in separate thread, doesn't block main program. Tested and documented. Doesn't break accented dead keys (I'm looking at you, pyHook). Mouse support available via project mouse (pip install mouse).

From README.md:

import keyboard

keyboard.press_and_release('shift+s, space')

keyboard.write('The quick brown fox jumps over the lazy dog.')

# Press PAGE UP then PAGE DOWN to type "foobar".
keyboard.add_hotkey('page up, page down', lambda: keyboard.write('foobar'))

# Blocks until you press esc.
keyboard.wait('esc')

# Record events until 'esc' is pressed.
recorded = keyboard.record(until='esc')
# Then replay back at three times the speed.
keyboard.play(recorded, speed_factor=3)

# Type @@ then press space to replace with abbreviation.
keyboard.add_abbreviation('@@', '[email protected]')
# Block forever.
keyboard.wait()

There is a way to do key listeners in python. This functionality is available through pynput.

Command line:

$ pip install pynput

Python code:

from pynput import keyboard
# your code here

Although I like using the keyboard module to capture keyboard events, I don't like its record() function because it returns an array like [KeyboardEvent("A"), KeyboardEvent("~")], which I find kind of hard to read. So, to record keyboard events, I like to use the keyboard module and the threading module simultaneously, like this:

import keyboard
import string
from threading import *


# I can't find a complete list of keyboard keys, so this will have to do:
keys = list(string.ascii_lowercase)
"""
Optional code(extra keys):

keys.append("space_bar")
keys.append("backspace")
keys.append("shift")
keys.append("esc")
"""
def listen(key):
    while True:
        keyboard.wait(key)
        print("[+] Pressed",key)
threads = [Thread(target=listen, kwargs={"key":key}) for key in keys]
for thread in threads:
    thread.start()