fleytman/python-readchar

Python library to read characters and key strokes

python-readchar

Library to easily read single chars and keystrokes.

Born as a python-inquirer requirement.

Installation

simply install it via pip:

pip install readchar

or download the source code from PyPi.

Usage

Usage example:

import readchar

c = readchar.readchar()
key = readchar.readkey()

API

There are just two methods:

readchar(blocking=True) -> str | None

Reads the next char from stdin, returning it as a string with length 1.

By default, it will block until a character is available, but if you pass blocking=False the function will not block and return None if no character is available.

readkey() -> str

Reads the next keystroke from stdin, returning it as a string. Waits until a keystroke is available.

A keystroke can be:

• single characters as returned by readchar(). These include:
  • character for normal keys: 'a', 'Z', '9'...
  • special characters like 'ENTER', 'BACKSPACE', 'TAB'...
  • combinations with 'CTRL': 'CTRL'+'A',...
• keys that are made up of multiple characters:
  • characters for cursors/arrows: 🡩, 🡪, 🡫, 🡨
  • navigation keys: 'INSERT', 'HOME',...
  • function keys: 'F1' to 'F12'
  • combinations with 'ALT': 'ALT'+'A',...
  • combinations with 'CTRL' and 'ALT': 'CTRL'+'ALT'+'SUPR',...

Attention!

'CTRL'+'C' will not be returned by readkey(), but instead raise a KeyboardInterupt. If you what to handle it yourself, use readchar(). Also note that using the none-blocking version may result in unexpected behaviour for KeyboardInterupt.

key.py module

This submodule contains a list of available keys to compare against. You can use it like this:

from readchar import readkey, key

while True:
  k = readkey()
  if k == key.UP:
    # do stuff
  if k == key.DOWN:
    # do stuff
  if k == key.ENTER:
    # do stuff

OS Support

This library support both Linux and Windows, but on Windows the key submodule has fewer keys available.

Currently unsupported, but enabled operating systems:

• macOS
• FreeBSD

Theoretically every Unix based system should work, but they will not be actively tested. It is also required that somebody provides initial test results before the OS is enabled and added to the list. Feel free to open a PR for that.

Thank you!

How to contribute

You can download the code, make some changes with their tests, and open a pull-request.

In order to develop and run the tests, follow these steps:

1. Clone the repository.

git clone https://github.com/magmax/python-readchar.git

2. Create a virtual environment:

python -m venv .venv

3. Enter the virtual environment

source .venv/bin/activate

4. Install dependencies

pip install -r requirements.txt

5. Install the local version of readchar (in edit mode, so it automatically reflects changes)

pip install -e .

6. Run tests

make

Please, Execute the tests before any pull-request. This will avoid invalid builds.

Licence

Copyright (c) 2014-2022 Miguel Angel Garcia (@magmax_en).

Based on previous work on gist getch()-like unbuffered character reading from stdin on both Windows and Unix (Python recipe), started by Danny Yoo as well as gist kbhit.py by Michel Blancard.

Licensed under the MIT licence.