When opening a new session, MAM clients might want to use the most-recent known XEP-0359 stanza ID to sync messages. One problem they face is that there's no way to figure out the stanza ID of outgoing messages, short of actually querying them back from MAM. Therefore, a common workaround is to use the stanza ID of the most-recent _incoming_ message and then de-dup any outgoing messages returned from MAM.
I think it would be good to find a better solution. The issue has been discussed before, and I've seen at least the following suggestions: 1. Let XEP-0198 include the stanza ID with the stream management ACK. I like the idea of acknowledging the stanza and returning its ID in one go, but one concern I heard is that this might not play well with existing APIs: libraries may handle stream management transparently, while dealing with MAM sync is left to the application layer. 2. Let XEP-0280 carbon-copy messages back to the sender. Presumably the solution that requires the least-intrusive changes, both spec- and implementation-wise. The downside I see is that the entire (XEP-0280-wrapped) message stanza is reflected just to return the stanza ID. 3. Let clients subscribe to XEP-0313 archiving, as suggested here, for example: https://geekplace.eu/xeps/xep-mamsub/xep-mamsub.html Would involve more changes, but might remove the need for XEP-0280 altogether, which could be a nice goal in itself. However, it has the same downside as solution (2). I'd prefer a solution that doesn't involve reflecting the entire stanza just to make the client aware of the stanza ID. So if (1) is not an option, I think I'd opt for extending XEP-0359 or XEP-0313 (or, if people prefer, adding a new XEP) to return an ACK for outgoing 1:1 messages. E.g., something like this: | <message> | <ack xmlns='urn:xmpp:sid:0' id='42' stanza_id='1234'/> | </message> Thoughts? Holger _______________________________________________ Standards mailing list Info: https://mail.jabber.org/mailman/listinfo/standards Unsubscribe: standards-unsubscr...@xmpp.org _______________________________________________
