Launch an application with KDocker from its desktop file.

kdocker-launch

#!/usr/bin/env python3

import argparse
import os
import re
import shlex
import shutil
import subprocess

# pyxdg; https://freedesktop.org/wiki/Software/pyxdg/
from xdg.DesktopEntry import DesktopEntry
from xdg import IconTheme


for bin in ['kdocker', 'xdotool']:
    if not shutil.which(bin):
        raise Exception(f"Missing dependency, could not find executable: {bin}")


def file(path):
    if os.path.isfile(path):
        return path
    else:
        raise Exception('Could not find specified desktop file')

parser = argparse.ArgumentParser(
    description='Launch an application with KDocker from its desktop file.')
parser.add_argument('-d', '--avoid-launch', action='store_true',
        help="dock an existing window if possible")
parser.add_argument('-D', '--dock-only', action='store_true',
        help="dock an existing window instead of launching the app")
parser.add_argument('-c', '--click', action='store_true',
        help="select the window to dock by clicking on it")
parser.add_argument('-n', '--name', action='store_true',
        help="use the name/title instead of WMClass to match the window")
parser.add_argument('path', type=file, help='Path to a desktop file')
args = parser.parse_args()


def find_window(de, wait=True):
    # I could not make KDocker match the windows' title with '-n', and I'm not
    # sure why...
    # So instead the matching is done manually and the result is fed to KDocker.
    # This adds a dependency to an external program, but also allows matching on
    # other attributes, like the WMClass which seems to be more robust.

    wmclass = de.getStartupWMClass()
    appname = de.getName()

    cmd = ['xdotool', 'search', '--onlyvisible', '--limit', '1']
    if wait:
        cmd += ['--sync']

    if wmclass and not args.name:
        cmd += ['--classname', re.escape(wmclass)]
    else:
        cmd += ['--name', re.escape(appname)]

    return subprocess.run(
        cmd,
        check=wait, timeout=5,
        capture_output=True, text=True
    ).stdout.strip()


de = DesktopEntry()
de.parse(args.path)

kdargs = []

if icon := de.getIcon():
    # The Icon value can be either already an absolute path, or a name which
    # needs to be looked up.
    icon = IconTheme.getIconPath(icon)
    kdargs += ['-i', icon]

if not (args.dock_only or (args.avoid_launch and find_window(de, wait=False))):
    # KDocker is not able to target correctly windows of apps that launch
    # separate processes, or processes that own multiple windows that should be
    # docked independently.
    # PWAs installed with Chrome can fall into both categories, as chrome reuses
    # the first process that was launched for subsequent windows, leading to a
    # confusing situation where the first PWA to launch is correctly docked as
    # long as there is no existing Chrome window, but the following PWAs aren't.
    # To work around this, the app is first launched "in the background", then
    # KDocker is called separately to dock the window.
    subprocess.Popen(shlex.split(de.getExec()))

if not args.click:
    kdargs += ['-w', find_window(de)]

try:
    subprocess.run(['kdocker', *kdargs], check=True)
except KeyboardInterrupt:
    pass