Get last message of each conversation with XEP-0313? - xmpp

Question

I'm using an XMPP server that implements XEP-0313 for retrieving conversation history. I would like to fetch only the last message of each conversation, so that I can build a list of your most recent conversations previewing the last message.
I've managed to fetch all messages of all conversations and based on that I could build the list, but it's a big waste of data and not an option. I'm not sure this is the right extension for accomplishing this, so if there is another extension I should be looking at, please guide me in the right direction.

Answer 1

One thing you can do easily is first retrieve the user's roster and then for each contact retrieve the latest message.
<iq from='juliet#example.com/balcony'
id='bv1bs71f'
type='get'>
<query xmlns='jabber:iq:roster'/>
</iq>
Result:
<iq id='bv1bs71f'
to='juliet#example.com/chamber'
type='result'>
<query xmlns='jabber:iq:roster' ver='ver7'>
<item jid='nurse#example.com'/>
<item jid='romeo#example.net'/>
</query>
</iq>
Retrieve the last message from or to nurse#example.com:
<iq type='set' id='juliet1'>
<query xmlns='urn:xmpp:mam:1'>
<x xmlns='jabber:x:data' type='submit'>
<field var='FORM_TYPE' type='hidden'>
<value>urn:xmpp:mam:1</value>
</field>
<field var='with'>
<value>nurse#example.com</value>
</field>
</x>
<set xmlns='http://jabber.org/protocol/rsm'>
<max>1</max>
<before/>
</set>
</query>
</iq>
Of course users can have conversations with people not on their roster, but in practice this is quite rare on XMPP.