[KDE ONLY][Python3+] Automatically change your default browser when changing activities on KDE.

monitor-activities.py

#!/path/to/python3

""""
If running as an executable:
    Don't forget to chmod +x this file when adding it as a service.
    And Also don't forget to modify the /path/to/python above

Requirements:
dbus-python: https://dbus.freedesktop.org/doc/dbus-python/index.html (pip install dbus-python)
gi-repository: https://pygobject.readthedocs.io/en/latest/getting_started.html (follow instructions on website)
sh: https://amoffat.github.io/sh/ (pip install sh)
"""
import getpass

import dbus
from dbus import SessionBus
from dbus.mainloop.glib import DBusGMainLoop
import logging
from sh import kreadconfig5, kwriteconfig5, qdbus, RunningCommand

# make sure we run as the user and not system or anything else
# running as '~/.config/kdeglobals' does not work on my system
kde_globals = f'/home/{getpass.getuser()}/.config/kdeglobals'
service = 'org.kde.ActivityManager'
interface = service + '.Activities'
path = '/ActivityManager/Activities'
signal = 'CurrentActivityChanged'

logging.basicConfig()
logger = logging.getLogger('monitor-activities')
logger.setLevel(logging.INFO)


def read_conf() -> str:
    # kreadconfig5 --file ~/.config/kdeglobals --group General --key BrowserApplication
    cur_browser = kreadconfig5(file=kde_globals,
                               group='General', key='BrowserApplication')  # type: RunningCommand
    return str(cur_browser).strip()


def write_conf(text) -> None:
    #  kwriteconfig5 --file ~/.config/kdeglobals --group General --key BrowserApplication "$1"
    kwriteconfig5(f'--file={kde_globals}', '--group=General', '--key=BrowserApplication',
                  text)  # type: RunningCommand


def filter_cb(_: SessionBus, message: dbus.lowlevel.SignalMessage) -> None:
    # [ "$member" == "$signal" ] || continue
    if message.get_member() != "CurrentActivityChanged":
        return
    try:
        # curact=$(qdbus $service $path $interface.CurrentActivity)
        current_activity = str(qdbus(service, path, interface + '.CurrentActivity')).strip()

        # name="$(qdbus $service $path $interface.ActivityName $curact)"
        name = str(qdbus(service, path, interface + '.ActivityName', current_activity)).strip()
        #  echo "Previous browser is $(readconf)"
        logger.info('Previous browser was %s', read_conf())

        # These suited me perfectly. Change it to your liking :)
        if name == 'Default':
            write_conf('brave.desktop')
        elif name == 'Work':
            write_conf('chromium.desktop')
        elif name == 'Research':
            write_conf('opera.desktop')
        else:
            write_conf('firefox.desktop')

        # echo "Switched to activity $name"
        logger.info('Switched to %s', name)

        # echo "Current Browser is $(readconf)"
        logger.info('Current browser is %s', read_conf())
    except Exception as e:
        logger.exception(e)


def monitor() -> None:
    # dbus-monitor --profile "type=signal,path=$path,interface=$interface,member=$signal"
    DBusGMainLoop(set_as_default=True)
    bus = dbus.SessionBus()
    bus.add_match_string(f'type=signal,path={path},interface={interface},member={signal}')
    bus.add_message_filter(filter_cb)

    # Monitoring process
    from gi.repository import GLib
    loop = GLib.MainLoop()
    loop.run()


monitor()