ruff-quick-action.py

"""
Format stdin with ruff to stdout

When formatting fails, append error message

For use in an Automator Quick Action (Run Shell Script),
accessible everywhere via right click -> Services > ruff format,
or global keyboard shortcut registered in System Settings > Keyboard > Keyboard Shortcuts

Find the action under Services
"""

# SPDX-License-Identifier: CC0-1.0
# public domain, no rights reserved

import sys
from subprocess import run

ruff_exe = "/opt/homebrew/bin/ruff"

source = sys.stdin.read()

p = run(
    [ruff_exe, "format", "-"], input=source, capture_output=True, text=True, check=False
)

if p.returncode:
    # format failed (probably SyntaxError), keep original code and append error
    print(source)
    print(p.stderr)
else:
    print(p.stdout)

ruff-quick-action.sh

#!/bin/sh
# lighter version using just sh
src=$(cat -)
# pipe error to stdout, so error messages are captured
echo "$src" | /opt/homebrew/bin/ruff format - 2>&1
exit_code=$?
if [ $exit_code -ne 0 ]; then
  # if error, echo original source
  # since we are replacing text
  # error message will be at the top
  echo "$src"
fi
echo  # trailing newline

To use this:

Step 1. create a new Automator workflow. Select Quick Action

Step 2: just one step, Run Shell Script with the above Python code (Shell: /usr/local/bin/python3), or shell script (Shell: /bin/sh)

Settings:

• Workflow receives current text in any application
• Check Output replaces selected text

Step 3 (optional): Register global keyboard shortcut. Pick one that's available in every application you might use this (hard!), and set it for your Quick Action in System Settings > Keyboard > Keyboard Shortcuts > Services:

While you're there, probably uncheck lots of things registered by applications that you've never used.

Now you can format code in any text box anywhere, by keyboard shortcut or right-click, including in GitHub or forum comments!