WSGIEchoIP

$ curl -L ip.jb2170.com
12.34.56.78

A simple WSGI app that returns the value of the X-Forwarded-For header, so one can get their public IP address.

No more need for $ curl -L -D - ipconfig.org and its unnecessary cookies!

This is a useful 'just-werks' app, and demonstrates using WSGI without a framework such as Flask. The only thing to really be aware of in raw WSGI is that strings are bytes decoded as Latin-1, as per PEP-3333, when in reality there's a 99% chance the bytes should've been decoded as UTF-8. Therefore if one is concerned about Unicode headers etc the WSGI environment strings should be corrected with .encode("latin1").decode("utf8"). This is one of the many reasons to use a framework like Flask in a production app.

Installing

I run this as a reverse proxy via Apache. Example systemd unit files and friends are in daemon-files of this repo

• create a venv, say in ~/.local/var/lib/WSGIEchoIP, and source it
• $ pip install WSGIEchoIP gunicorn
• place the systemd unit file and shell script into the correct folders, for example I use ~/.local/var/lib/systemd/{etc/user,usr/bin}
• place the .htaccess file in the public http folder corresponding to the domain you want to serve the app from
• adjust the unix socket path in the .htaccess file and .service unit

Make sure you have the headers, proxy, and proxy_http modules enabled for Apache!

You can probably figure out the rest, enabling / starting the systemd service...

Customizing

Setting the environment variable FORWARDED_IP_HEADER_NAME=X-Sneed-Chuck makes the app return the X-Sneed-Chuck header value instead. (perhaps nginx uses something different than X-Forwarded-For.)

See also

• FlaskEchoIP, a Flask version of this app that I also made, which is why this one is now archived