I just switched to use i3blocks for my i3 bar. I found this post on how to set the active window title that uses xtitle. Not to be confused with ubuntu's apt xtitle which sets the window title. This different utility is to read the window title.

It comes with a handy Makefile, but I didn't have the dependencies to get it compiled. These are the Ubuntu packages I needed to install:

libxcb-icccm4-dev 
libxcb-ewmh2
libxcb-util-dev 
libxcb1-dev