[Standards] XEP-0115: verification string, and changing caps over time

Alban Crequy alban.crequy at collabora.co.uk
Tue May 6 09:44:10 UTC 2008


Hi,

When a client receives a service discovery query with a verification
string that does not correspond to its current caps, what must it reply?

My full scenario is:

1. my jabber client publishs its <presence> with a verification string.
2. a remote client receives the presence.
3. the remote client sends a service discovery query with this
verification string.
4. my jabber client updates its caps (it has plugins) and publishs its
new <presence> with a new verification string.
5. my jabber client receives the service discovery query from step 3.
The verification string does not correspond to my current caps.

What should my jabber client reply?

If it replies with the current caps, it is just wrong and the
verification string fails. Replying with the old caps looks like a lie
and it means the client has to cache all its previous caps sets. Can it
replies an error "too late, my caps changed, please ask again with the
new verification string"?

-- 
Alban



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