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BarnOwl Modules

BarnOwl Modules are perl packages that live in the BarnOwl::Module:: namespace. There are two ways to install a module such that BarnOwl will recognize it:

  • As a directory tree: You can install the MyModule module with a directory named MyModule containing the file lib/BarnOwl/Module/
  • As a PAR package containing lib/BarnOwl/Module/

In both cases, the lib/ directory will be added to perl's library path when your module is loaded, so you can include additional modules there, either to include dependencies or just to divide module code into other perl modules.

Modules can be located in either of two directories, the system module path, or the user module path. By default the user module path is at ~/.owl/modules but this can be overridden with command-line options.

Building a BarnOwl Module

Building a BarnOwl module is easy. The only file required is the .pm Therefore, a minimal module simply contains the directory tree mentioned above, and you can start using the BarnOwl APIs.

Distributing a BarnOwl Module

BarnOwl includes a Module::Install plugin to make deploying modules as PAR files easier. Simply create a Makefile.PL in the top level of your module directory containing:

  #!/usr/bin/env perl
  use strict;
  use warnings;
  use inc::Module::Install;

You can then run perl Makefile.PL and make MyModule.par to automatically generate a .par file that you can deploy to other BarnOwl users.

Note that the first time you run perl Makefile.PL you will need to add BarnOwl's system library path to your $PERL5LIB On Athena, you would do this like:

  env PERL5LIB=/mit/barnowl/share/barnowl/lib perl Makefile.PL
  make MyModule.par


The BarnOwl Source includes two modules, for Jabber and IRC which are moderately complex examples of how to write a module that implements a new protocol for BarnOwl.

nelhage has written a number of small useful modules, that are also intended to be good examples for learning. They can be found in AFS at /afs/ or on the web at