Rescuetime is a great little app that tracks how you use your time on your computer and then shames you for not being productive enough. I got into it recently and installed it in my browser and on my phone, and tried to install it on my laptop. But of course it didn’t work, because I use dwm, and why would dwm work with anything out of the box? But I wanted to get it working so I sent in a support ticket.

After I told them my window manager was dwm the support guy responded:

Hello. This was our Linux developer’s reply to me: The following commands must work for RescueTime to work:

xprop -id `xprop -root | grep "_NET_ACTIVE_WINDOW(WINDOW)" | cut -d# -f2 | cut -d, -f1` | grep "NET_WM_PID" | cut -d"=" -f2 2>/dev/null
xprop -id `xprop -root 2>/dev/null | grep "_NET_ACTIVE_WINDOW(WINDOW)" | cut -d# -f2 | cut -d, -f1` 2>/dev/null | grep "WM_CLASS(STRING)" | cut -d"\"" -f4 2>/dev/null
xprop -id `xprop -root 2>/dev/null | grep "_NET_ACTIVE_WINDOW(WINDOW)" | cut -d# -f2 | cut -d, -f1` 2>/dev/null | grep "WM_NAME(STRING)\|WM_NAME(COMPOUND_TEXT)" | cut -d"\"" -f2 2>/dev/null

“our Linux developer”. Must be lonely.

Doing some investigation (pulling up the terminal and running the above commands) revealed that the commands indeed did not work. For some reason xprop -root did not return any row which contained "_NET_ACTIVE_WINDOW(WINDOW)". Interesting.

Of course, when you use a window manager as niche as dwm googling “dwm no _NET_ACTIVE_WINDOW(WINDOW) in xprop -root” doesn’t really get you very far. But I figure there’s someone else out there that uses both dwm and RescueTime, so I wrote this blog post so that their desperate googling will no longer be in vain. I did the hard work of trawling through the dwm mailing list archives to find the thread about supporting _NET_ACTIVE_WINDOW, which contained an email from a fine fine man named Andreas Amann, who wrote a patch to add _NET_ACTIVE_WINDOW support which has a permalink here: https://lists.suckless.org/dev/att-10649/netactivewindow.

Here’s to that one other dwm/ResueTime user. I hope this saves you an hour or two.