[JDEV] From the crude hack department

[Piers Harding]

Jarl is great!  Perl is great!

The other day when I was trying to test out some headline viewing
integration with pubsub, I had the problem of clients not being able to
support new packet types etc.
So....  I modifeid Jarl!

In JEP 0024 the packet type for pushed subscription data is an IQ - but
the payload can be anything eg:
<iq type='set' to='pubsub component' id='p1'> 
  <query xmlns='pipetree:iq:pubsub'> 
    <publish xmlns='peerkat:home:weblogs:jabber:test'> 
      <item xmlns='peerkat:home:weblogs:jabber:test'> 
        <title>the title</title> 
        <link>http://the.link</link> 
        <description>this is the description</description> 
      </item> 
    </publish> 
  </query> 
</iq> 

Basically all I need t odo was to munge this dat aarround so that it
looked like a <message type="headline"/>.  So using a combination of
Jabber::NodeFactory and Net::Jabber I only had to do two things.

(a) at arround line 712 of jarl I changed the receive callback to look
like:
 $jabber{client}->SetCallBacks(message=>\&messageCB,
                                presence=>\&presenceCB,
                                iq=>\&iqCB,
                                send=>\&jarlDebug_AddSendXML,
                                receive=>\&my_iq_CB);

(b) I inserted my own custom callback to handle both debug packets and
whatever I want to do ( which is create headlines ).

The real bit of magic is this subroutine which takes a packet and
generates a headline- this to me is the real magic, as jarl has
subroutines for all these events, which means you can easily roll all
your own custom payload packets in.

         &jarlHeadlineIF_AddMessage($mess);


Note: I have picked up the debugging of packets by mannually calling
&jarlDebug_AddReceiveXML( @_ );



sub my_iq_CB {

  my ( $sid, $xml )  = @_;
# $xml is the string of xml

# make sure you still get debug
  &jarlDebug_AddReceiveXML( @_ );

  $Debug->Log1("my_iq_CB: start");

# parse the xml so that I can easily manipulate it
  use Jabber::NodeFactory;
  my $jcnf = new Jabber::NodeFactory(fromstr => 1);
  my $n = $jcnf->newNodeFromStr($xml);
  return unless $n->name() eq "iq";

  my $query = $n->getTag('query');
  return unless $query;
  return unless $query->attr("xmlns") eq "jabber:iq:pubsub";

  print STDERR "WE HAVE A PUBSUB: $xml ....";

 # now create the headline packet and then call the magic
  foreach my $pub ( $query->getChildren() ){
    next unless $pub->name() eq "publish";
    foreach my $item ( $pub->getChildren() ){
      next unless $item->name() eq "item";
        my $mess = new Net::Jabber::Message();
        $mess->SetMessage(
                        to => $n->attr('to'),
                        from => $n->attr('from'),
                        type => 'headline',
                        subject => $item->getTag("title")->data(),
                        body => $item->getTag("link")->data()." -
".$item->getTag("description")->data(),
                        );

#  this is the magic
         &jarlHeadlineIF_AddMessage($mess);
    }
  }

  $Debug->Log1("my_iq_CB: end");
}

Cheers.