Ghost sessions

[Zash]

Observation: Many of copies of the same stanza like <message type="groupchat" from="#[email protected]" to="[email protected]/RANDOM_VARYING">

Theory: When disconnecting, sometimes the <presence type="unavailable"/> does not make it to the bridge. If the server policy is to generate a random resource (the JID resource part is a session identifier, not a device identifier!) then these eventually add up in MUCs and the like if not removed.

Background: In XMPP / MUC, clients that silently go offline without the MUC being told end up as "ghosts", appearing to be still present but aren't. These are normally removed when an attempt to deliver a groupchat message to them results in an error returned to the MUC. These kinds of problems were common in XMPP long ago, but were mostly fixed.

Solution: Watch for <message type="error"> in response to groupchat messages, check whether the error condition points to non-deliverability (e.g. one of these) and then remove the user.

Might be a duplicate of #53

[Half-Shot]

I think this definitely warrants further investigation.

[bqv]

Morgan Freeman: But no further investigation occured.