Page 261 - Asterisk™: The Future of Telephony

• Pattern matching
• Usage consistency
• Source code organization
Many people addressed these matters by writing the advanced logic in external pro-
grams such as Perl and PHP, and connecting to Asterisk via AMI and AGI. Unfortu-
nately, while the desired power was now available, these interactions did not always
simplify things for the developer. To the contrary, they often made development more
complex. Using existing technologies in Asterisk, but aiming to deliver power and sim-
plicity, Adhearsion has a new approach.

Asterisk Development with Adhearsion
Adhearsion is an open source (LGPL) framework that is designed to improve Asterisk
solution development. It rests above an Asterisk system, handling parts or all of the
dialplan and, in a few unique ways, manages access to Asterisk with several improved
interfaces. Because it runs as a separate daemon process and integrates through the
already-present Gateway (AGI) and Manager (AMI) interfaces, configuring a context
to use Adhearsion is as simple as adding a few lines to your dialplan or adding a user
to manager.conf.
Adhearsion primarily uses the highly dynamic, object-oriented Ruby programming
language, but has optional support for other languages such as C or Java. In the VoIP
world, many things exist as conceptual objects, which means that object-oriented pro-
gramming can make a lot of sense. Those familiar with Python, Perl, or other scripting
languages should have no trouble picking up Ruby, and for those who don’t, Ruby is
an excellent choice for your first scripting language.

Installing Adhearsion

Ruby software is generally installed through Ruby’s package manager (similar to Linux
package managers, but for the Ruby platform exclusively). Adhearsion exists as a gem
in the standard RubyGems trove so, with Ruby and RubyGems installed, Adhearsion
is only one install command away.

Installing Ruby/RubyGems on AsteriskNOW

AsteriskNOW comes standard with Ruby but not RubyGems (for support reasons).
Thankfully, RubyGems can be easily installed from the Ruby rPath trove with the fol-
lowing command:

conary update rubygems=ruby.rpath.org@rpl:devel
source /etc/profile

Asterisk Development with Adhearsion | 233