Programming Jabber

The setup_Jabber() function

Here we define the setup_Jabber() function, which is called to set up the connection to the Jabber server and authenticate with a predefined user:

# Set up Jabber client connection, sending intial presence
sub setup_Jabber {
  my ($server, $port, $user, $pass, $resource, $initial_status) = @_;
  my $connection = new Net::Jabber::Client;

  # Connect
  my $status = $connection->Connect( hostname => $server,
                                     port     => $port );
  die "Cannot connect to Jabber server $server on port $port\n"
    unless $status;

  # Callbacks
  $connection->SetCallBacks( presence => \&InPresence );

  # Ident/Auth
  my @result = $connection->AuthSend( username => $user,
                                      password => $pass,
                                      resource => $resource );
  die "Ident/Auth failed: $result[0] - $result[1]\n"
    if $result[0] ne "ok";

  # Roster
  $connection->RosterGet();

  # Initial presence dependent upon initial status
  &set_presence($connection, $initial_status);

  return $connection;
}

First, we instantiate a new Net::Jabber::Client object. Net::Jabber distinguishes between client- and component-based connections to Jabber; the component-based equivalent of this class is Net::Jabber::Component. The Connect() method is passed arguments that specify the hostname and port of the Jabber server to connect to. It returns a 0 status if the connection could not be made.

We can register handlers for Jabber elements received over the XML stream carried by the connection we just made. Here we are interested in incoming presence subscription or unsubscription ...