[Standards-JIG] Re: Ad-hoc Commands and nesting
trejkaz at trypticon.org
Sun Jan 23 00:52:17 UTC 2005
On Sunday 23 January 2005 05:08, Nolan Eakins wrote:
> The idea that sent me back to this thread is about Service disco in
> general. I don't know if this is possible, but I don't see why it should
> not be: can a disco#items query return a list of items that are a mix of
> ~ say Pubsub nodes, adhoc commands, branches, clients, and any other
> service disco#item? This may require an additional attribute or two be
> added to the <item/> elements or a child element. Would this be desirable?
It can already be done without adding attributes. The <item/> elements inside
a disco#items query don't give any indication of their type. A client needs
to perform an extra disco#info query on each node to be completely sure what
This is why in Psi, for example, the names of some items in the discovery can
change a few seconds after appearing, because the names in the disco#items
and disco#info queries were different due to naughty servers or whatever.
Nothing illegal about it, it just confuses the user. :-)
My main issue with the JEP-50 spec is that at present, there isn't a way
specified to do branches at all. So what it effectively says is, "every item
which comes back from the query is a command." This is dangerous if someone
_does_ put branches in, because any client which took this to be a way to
optimise the number of queries they perform, may attempt to execute a node
which is not actually a command, but a branch.
So we need _some_ way to do a branch, which needs to be specified in JEP-50 so
that client implementations know they really do need to do a disco#info query
to determine that something really is a command that can be executed. At the
moment I'm leaning towards the "branch" identity, because "command-list" in
the registry is said to only exist on the (singular) "commands" node.
Email: Trejkaz Xaoza <trejkaz at trypticon.org>
Web site: http://xaoza.net/
Jabber ID: trejkaz at jabber.zim.net.au
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