Set_Wallpaper.py

#!/usr/bin/python
 
'''Uses Cocoa classes via PyObjC to set a desktop picture on all screens.
Modified script to read from com.apple.desktop via MCX
 
Tested on Mavericks.
 
See:
https://developer.apple.com/library/mac/documentation/cocoa/reference/applicationkit/classes/NSWorkspace_Class/Reference/Reference.html
 
https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSURL_Class/Reference/Reference.html
 
https://developer.apple.com/library/mac/documentation/cocoa/reference/applicationkit/classes/NSScreen_Class/Reference/Reference.html
 
http://docs.python.org/dev/library/plistlib.html
 
Based on conversations
http://derflounder.wordpress.com/2013/10/26/mavericks-desktop-background-picture-settings-moved-from-librarypreferencescom-apple-desktop-plist/
https://groups.google.com/forum/?fromgroups#!topic/macenterprise/zVDzyOwxJoM
 
Original script by Greg Neagle
Modified by Erik Gomez with guidance from Greg Neagle
'''
 
import os
import glob
import plistlib
import getpass

from AppKit import NSWorkspace, NSScreen
from Foundation import NSURL
from CoreFoundation import *

# Grab the full path from com.apple.desktop MC X value 
''' Original idea did not work, but leaving it here.
pathtomcx = os.path.expanduser("/Library/Managed Preferences")
username = getpass.getuser()
pathtoplist = os.path.join(pathtomcx, username, 'com.apple.desktop.plist')
desktopwall = plistlib.readPlist (pathtoplist)
desktopwall_path = desktopwall["Background"]["default"]["ImageFilePath"]
'''

bundle_id = 'com.apple.desktop'
desktopwall = CFPreferencesCopyAppValue("Background", bundle_id)
desktopwall_path = desktopwall["default"]["ImageFilePath"] 

'''pictures_glob = glob.glob("/Library/Desktop Pictures/*.jpg")
picture_path = random.choice(pictures_glob)
'''

# generate a fileURL for the desktop picture
file_url = NSURL.fileURLWithPath_(desktopwall_path)

# make image options dictionary
# we just make an empty one because the defaults are fine
options = {}

# get shared workspace
ws = NSWorkspace.sharedWorkspace()

# iterate over all screens
for screen in NSScreen.screens():

# tell the workspace to set the desktop picture
	(result, error) = ws.setDesktopImageURL_forScreen_options_error_(
		file_url, screen, options, None)