How to get the list of open windows from xserver

Question

Anyone got an idea how to get from an Xserver the list of all open windows?

Answer 1

Building off of Marten's answer, (assuming your window manager supports Extended Window Manager Hints) you can feed that list of window ids back into xprop to get the _NET_WM_NAME property:

$ xprop -root _NET_CLIENT_LIST |
    pcregrep -o1 '# (.*)' |
    sed 's/, /\n/g' |
    xargs -I{} -n1 xprop -id {} _NET_WM_NAME

But at the command line, it would just be easier to use wmctrl:

$ wmctrl -l

Programmatically, with python-xlib, you can do the same with:

#!/usr/bin/env python
from Xlib.display import Display
from Xlib.X import AnyPropertyType

display = Display()
root = display.screen().root

_NET_CLIENT_LIST = display.get_atom('_NET_CLIENT_LIST')
_NET_WM_NAME = display.get_atom('_NET_WM_NAME')

client_list = root.get_full_property(
    _NET_CLIENT_LIST,
    property_type=AnyPropertyType,
).value

for window_id in client_list:
    window = display.create_resource_object('window', window_id)
    window_name = window.get_full_property(
        _NET_WM_NAME,
        property_type=AnyPropertyType,
    ).value
    print(window_name)

Or, better yet, using the EWMH library:

#!/usr/bin/env python
from ewmh import EWMH

window_manager_manager = EWMH()
client_list = window_manager_manager.getClientList()

for window in client_list:
    print(window_manager_manager.getWmName(window))