This is the simplest possible Flask app that lists all the IP addresses that connect to it.
It uses mkdir() to store the list of IP addresses to avoid needing a database at all.
You might need this if, say, you are running a tutorial on web development and you want to give your attendees an easy way to see a list of IP addresses of their peers, even if you are all behind IPv4 NAT.
Note that you will need to be on the same LAN as your students, and that you will need to figure out your own LAN IP address and share it with your students somehow. Also note that this code listens on port 8100 by default.
License: WTFPL.
Author: Asheesh Laroia asheesh@asheesh.org
To run it:
$ virtualenv . $ bin/pip install -r requirements.txt $ bin/python app.py