Python script to print the path to the image used as the desktop background of the focussed screen

desktopImageURLForScreen.py

#!/usr/bin/python
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/. */

from AppKit import NSScreen, NSWorkspace

def main():
    focussedScreen = NSScreen.mainScreen()
    if not focussedScreen:
        raise RuntimeError("mainScreen error")

    workspace = NSWorkspace.sharedWorkspace()
    if not workspace:
        raise RuntimeError("sharedWorkspace error")

    imageURL = workspace.desktopImageURLForScreen_(focussedScreen)
    if not imageURL:
        raise RuntimeError("desktopImageURLForScreen returned invalid URL")

    if not imageURL.isFileURL():
        raise RuntimeError("desktop image URL is not a file URL")

    print(imageURL.path())

if __name__ == '__main__':
    main()