A Perl API for dbus

[Daniel P. Berrange]

Last week I was looking around for a messaging system to 
let multiple Test::AutoBuild (www.autobuild.org) instances
co-ordinate their operation, and to notify applications
of build results/status. After considering XML::RPC,
and plain old HTTP, I decided on dbus. Unfortunately 
there was no Perl API in evidence, so having wanted an
opportunity to learn Perl-XS programming I wrote one...
It is by no means complete, but I've done enough that it
is potentially useful to people besides myself, hence
this mail

It is a minimal Perl+XS wrapper around the plain old C
APIs for dbus, written in a object-oriented perl style. 
It provides the following objects mapping onto the 
corresponding dbus APIs:

  DBus::Server - dbus_server_XXX
  DBus::Connection - dbus_connection_XXX
  DBus::Timeout - dbus_timeout_XXX
  DBus::Watch - dbus_watch_XXX
  DBus::Message - dbus_message_XXX
  DBus::Iterator - dbus_message_iter_XXX

For ease of construction, there are three trivial 
subclasses of Message:

  DBus::Message::Signal
  DBus::Message::MethodCall
  DBus::Message::MethodReturn
  DBus::Message::Error

And likewise a trivial connection subclass for
connecting to well known message buses:

  DBus::Bus

With the exception of the Iterator object, these
modules have pretty near complete coverage of the
C APIs. For Iterators, I still need to add support
for the array & dictionary datatypes.

In keeping with the style of the basic C API, there
are no external dependancies in this module, bar
Perl >= 5.8.0 (earlier Perl versions should work if
you grab Time::HiRes from CPAN). Aside from the 
basic API wrappers I've written

 * Unit tests for as much of the perl code as I
   can test without having to run a test server.
 * API documentation for core perl APIs
 * A pure perl event loop using select system
   call, with full support for timers & syntactic
   sugar for hooking up connection watch & timeout
   handlers

This is still very much work in progress, with things
I want to do:

  * More unit tests - its really rather hard testing
    multiplexed I/O in a single process!
  * Better error handling (mostly the out of memory
    return codes, and connection/server connect
    failure)
  * Finish Iterator API to support arrays & dictionaries
  * Finish off documentation
  * Change the Perl namespace to be Net::DBus

Once i do those bits & test its operation within my
original scenario (Test-AutoBuild) I'll consider it 
ready for general use, but if anyone wants to take a
look at it in the meanwhile, then my ViewCVS pages are

http://cvs.berrange.com/cgi-bin/viewcvs.cgi/freeware/DBus/

BTW, thanks to all those concerned for the good job on 
the plain C APIs - they were very easy to write a Perl 
wrapper to!

Regards,
Dan.
-- 
|=-            GPG key: http://www.berrange.com/~dan/gpgkey.txt       -=|
|=-       Perl modules: http://search.cpan.org/~danberr/              -=|
|=-           Projects: http://freshmeat.net/~danielpb/               -=|
|=-   berrange at redhat.com  -  Daniel Berrange  -  dan at berrange.com    -=|
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