In this project, you can see two ways of building an API on the Arduino Yún. In the first, you use a script built-in to OpenWrt-Yun to pass information from a web browser to the ATmega32u4. The second part of this project describes some of the limitations of building an API in this way. It shows how to build an API in Python on the Atheros AR9331 and pass information to the ATmega32u4 through the Console.
Your guide to Yún developement. Arduino Meets Linux includes:
Take your Arduino projects to the next level. This book shows you how.