Asterisk is the world's leading open-source PBX, telephony engine, and telephony applications toolkit with immense flexibility.

This book will give you a firm understanding of Asterisk Gateway Interface (AGI) development and proper AGI development practices. You will learn how to formulate Atomic AGI-enabled scripts, enabling rapid development within a well-defined Asterisk execution and runtime environment.

This book builds from the simplest form of an Asterisk application, the dialplan-based application, gradually building a full understanding of AGI scripting. The book also introduces a new concept of AGI development named "Atomic AGI" or "Particle Programming". It will introduce you to various techniques of interacting with the user, where user interaction isn't limited to keypad-based input, but also includes recording messages from the user, sending output to the user, and controlling the call flow.

The book takes a pragmatic approach with clear and complete examples, and a service development project -- allowing you to understand the project cycle of developing an Asterisk-based service or application.

What you will learn from this book?

* Create AGI applications with Asterisk easily using PHPAGI, a PHP class library
* Avoid going through the normal pitfalls of novice developers when developing Asterisk-based applications and services for the first time
* Develop AGI scripts and FastAGI servers using Asterisk-PERL modules
* Configure your AMI login information in the phpagi.conf file in order to utilize the AMI interface with PHPAGI
* Understand the Asterisk Manager Interface and its utilization in Asterisk applications
* Develop full web-based call-back platforms and highly interactive IVR applications using PHP and PHPAGI
* Learn proper development paradigms to easily scale your services and applications
* Get ideas for various Asterisk-based services and applications that you can create