Launching apps using a separate client running as active user

[joshgoebel]

This is trivial to add to existing configs by using a named pipe for one-way communication from server to client. The named pipe just needs to be located somewhere that your active user has access to.

First, make a FIFO that we can use for comms and set it's permissions properly:

sudo mkfifo -m644 /var/run/keyszer-launcher-sub
chown keymapper:keymapper /var/run/keyszer-launcher-sub

Then our config file might look something like this:

import os
LAUNCH_PIPE = "/var/run/keyszer-launcher-sub"

fd = os.open(LAUNCH_PIPE, os.O_RDWR)
launch_fifo = os.fdopen(fd, "w")

def launch(command):
    def launcher():
        launch_fifo.write(f"LAUNCH {command}")
        launch_fifo.flush()
    return launcher

# keymaps

keymap("default", {
  K("Cmd-Plus"): launch("raise-volume"),
  K("Cmd-Minus"): launch("lower-volume"),
})

And a simple Bash launch client:

#!usr/bin/env bash
file="/var/run/keyszer-launcher-sub"

while read -r line; do
    words=( $line )
    case ${words[0]} in
    LAUNCH)
      unset 'words[0]'
      cmd=${words[@]}
      case $cmd in
        raise-volume)
          pulsemixer --change-volume +5
          ;;
        lower-volume)
          pulsemixer --change-volume -5
          ;;
      esac
      ;;
    *)
      echo "Dunno what to do with: ${words[@]}"
      ;;
    esac

    #echo -e "$line\n"
done <$file