I missed these.
On Mon Jun 7 18:16:54 2010, Matthew Wild wrote:
Having recently implemented an initial version of XEP-0198
acknowledgements support for Prosody, I have some feedback:
1) I think section 8 (Stream Closure) of XEP-0198 needs to discuss
the
handling of unacknowledged stanzas.
I think clients should ensure that any and all stanzas are
acknowledged prior to closing the stream, otherwise confusion may
ensue.
Agreed.
2) I'm not sure how much sense it makes for the period between ack
requests to be determined by the number of sent stanzas. On inactive
streams stanzas could be received but remain unacknowledged for
extended periods of time. Surely it would make more sense to say
"Each
stanza should be acknowledged within X seconds of sending"?
I'd actually say "a reasonable time". What the maximum is varies
depending on network conditions.
3) Finally there's the handling of unacknowledged stanzas on
connection failure. It seems that bouncing the stanza with an error
is
the simplest approach, but the XEP suggests some smarter
alternatives
(which I like). However these have corner cases.
For example if the server was to handle the stanza as it would a
stanza to an unavailable resource, that stanza should go to another
resource or offline storage. However if there is a second resource
online, and it has the same priority, it quite possibly already
received that message. The same problem happens if that second
resource dropped connection too - you would end up with multiple
messages in offline storage.
I would note the corner case as an example of the pitfalls of
intelligent handling, rather than trying to identify every possible
scenario.
PS. What's the current consensus on splitting 0198 into separate
XEPs
for acknowledgement and resumption? I'm not sure the two are very
tighly bound, quite commonly one could be implemented/enabled
without
the other. Short XEPs are good :)
I don't see this as unreasonable, but I don't see this as required
either.
Dave.
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