The IP reporting service.
This tiny rack
-based application returns the client's IP address.
It also returns plain text, JSON, XML and YAML responses.
curl -H "Accept: text/plain" http://localhost:3000
curl -H "Accept: application/json" http://localhost:3000
curl -H "Accept: application/xml" http://localhost:3000
curl -H "Accept: application/x-yaml" http://localhost:3000