Result Set Management for Last Page (Reversed RSM) - xmpp

Question

I'm now developing an apps with message history retrieval based on XEP-0136 with Openfire Server.
I've read that message history retrieval can be combined with Result Set Management (RSM)-XEP-0059.
We can delimit the number of message retrieval request by setting max attribute of RSM like this:
<iq type='get' id='juliet1'>
<list xmlns='urn:xmpp:archive'
with='juliet#capulet.com'>
<set xmlns='http://jabber.org/protocol/rsm'>
<max>5</max>
</set>
</list>
</iq>
This should return the first 5 chat list from the top (ordered by chat time ascending).
My question is how to retrieve the last 5 chat list from the bottom, so I can get the latest chat message not the first time chat.
I've seen this Reversed RSM standard suggestion, like this:
<iq type='get' id='juliet1'>
<list xmlns='urn:xmpp:archive'
with='juliet#capulet.com'>
<set xmlns='http://jabber.org/protocol/rsm'>
<max>5</max>
<before />
<reversed />
</set>
</list>
</iq>
But this standard seems not yet implemented.
Thanks in advance

Answer 1

Based on this, the stanza is like this:
<iq type='get' id='juliet1'>
<list xmlns='urn:xmpp:archive'
with='juliet#capulet.com'>
<set xmlns='http://jabber.org/protocol/rsm'>
<max>5</max>
<before />
</set>
</list>
</iq>
You can retrieve the collection from bottom by RSM.
But seems Openfire message archiving plugin had some bugs with this RSM.
Reference: http://community.igniterealtime.org/message/230389#230389
So, the possible solution is getting count of my collection:
<iq type='get' id='juliet1'>
<list xmlns='urn:xmpp:archive'
with='juliet#capulet.com'>
<set xmlns='http://jabber.org/protocol/rsm'>
<max>0</max>
</set>
</list>
</iq>
It will return:
<iq xmlns='jabber:client' type='result' id='juliet1' to='admin#somehost'>
<list xmlns='urn:xmpp:archive'>
<set xmlns='http://jabber.org/protocol/rsm'>
<count>10</count>
</set>
</list>
</iq>
And I select the collection by index:
<iq type='get' id='juliet1'>
<list xmlns='urn:xmpp:archive'
with='juliet#capulet.com'>
<set xmlns='http://jabber.org/protocol/rsm'>
<max>5</max>
<index>4</index>
</set>
</list>
</iq>