On 2013-02-18 17:34, Kevin Smith wrote:
Folks,
It looks like purge_offline's behaviour in XEP-0060 is entirely
undefined. The pertinent bits seem to be:
1) That purge_offline means: "Whether to purge all items when the
relevant publisher goes offline"
2) That, when talking about a normal purge "a purge request MUST NOT
result in sending the same notifications as are sent when deleting
items (since purging a node with many persisted items could result in
a large number of notifications); instead, the node MUST send a single
notification to each subscriber, containing an empty <purge/> child
element."
and that's it.
So the closest thing I can see to prescribed behaviour is that when
doing a purge_offline because a publisher went offline their items are
silently removed and that if the node is now completely empty a
<purge.../> notification is sent. This still doesn't seem entirely
satisfying, but the only other option seems to be sending retract
notifications for all of the items removed, which (2) says a purge
explicitly MUST NOT do.
Thoughts?
As this feature was added for extended presence, I believe the
assumption here is that there is only one publisher: the owner of the
PEP node. As such I would interpret this option to mean that the node is
purged, i.e. all items are retracted with a single <purge/> notification
for each subscriber. Retracting only a subset of the items doesn't feel
like a purge to me.
Maybe this option is not very well suited for the case where there are
potentially multiple publishers, as one of them going offline would
result in the retraction of items published by others, too.
I agree this should be described better.
--
ralphm
