workspace_command.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Author: Serg Kolo , contact: 1047481448@qq.com 
Date: August 9th, 2016
Purpose: Spawns a command depending on current
         viewport, as defined in ~/.workspace_commands.json
Written for: http://askubuntu.com/q/56367/295286
Tested on: Ubuntu 16.04 LTS , Unity desktop


The MIT License (MIT)

Copyright © 2016 Sergiy Kolodyazhnyy <1047481448@qq.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE
"""


# Just in case the user runs 
# the script with python 2, import
# print function
from __future__ import print_function
import gi
gi.require_version('Gdk', '3.0')
from gi.repository import Gio,Gdk
import json
import subprocess
import os

def gsettings_get(schema,path,key):
    """Get value of gsettings schema"""
    if path is None:
        gsettings = Gio.Settings.new(schema)
    else:
        gsettings = Gio.Settings.new_with_path(schema,path)
    return gsettings.get_value(key)

def run_cmd(cmdlist):
    """ Reusable function for running shell commands"""
    try:
        stdout = subprocess.check_output(cmdlist)
    except subprocess.CalledProcessError:
        print(">>> subprocess:",cmdlist)
        sys.exit(1)
    else:
        if stdout:
            return stdout

def enumerate_viewports():
    """ generates enumerated dictionary of viewports and their
        indexes, counting left to right """
    schema="org.compiz.core"
    path="/org/compiz/profiles/unity/plugins/core/"
    keys=['hsize','vsize']
    screen = Gdk.Screen.get_default()
    screen_size=[ screen.get_width(),screen.get_height()]
    grid=[ int(str(gsettings_get(schema,path,key))) for key in keys]
    x_vals=[ screen_size[0]*x for x in range(0,grid[0]) ]
    y_vals=[screen_size[1]*x for x in range(0,grid[1]) ]
    
    viewports=[(x,y)  for y in y_vals for x in x_vals ]
    
    return {vp:ix for ix,vp in enumerate(viewports,1)}

def get_current_viewport():
    """returns tuple representing current viewport, 
       in format (width,height)"""
    vp_string = run_cmd(['xprop', '-root', 
                         '-notype', '_NET_DESKTOP_VIEWPORT'])
    vp_list=vp_string.decode().strip().split('=')[1].split(',')
    return tuple( int(i)  for i in vp_list )

def read_config_file():
    """ reads ~/.workspace_commands file """
    rcfile = os.path.join( os.path.expanduser('~'), 
                           '.workspace_commands.json')
    try:
        with open(rcfile) as config_file:
            config_data = json.load(config_file)
    except IOError as error:
        print(error.__repr__())
    else:
        if config_data:
            return config_data


def main():
   # get all the info we need first
   viewports_dict=enumerate_viewports()
   current_viewport = get_current_viewport()
   current_vp_number = viewports_dict[current_viewport]
   viewport_config = read_config_file()

   for vp,command in viewport_config.items():
       if int(vp) == current_vp_number:
          # spawn the command and let us exit
          pid = subprocess.Popen(command).pid
          break
   
if __name__ == '__main__':
    main()