[Standards-JIG] Re: UPDATED: JEP-0060 (Publish-Subscribe)

Peter Saint-Andre stpeter at jabber.org
Wed Jul 14 15:59:23 UTC 2004


On Fri, 09 Jul 2004 16:35:17 +0200, Ralph Meijer wrote:

> And even more:
> 
>  - Section 8.1.3 (Publish an Item to a Node), 3rd paragraph states:
> 
> 	 In order to facilitate authorization for item removal as shown in the
> 	 Delete an item from a node section below, implementations which support
> 	 persistent items SHOULD store the item (if the node is so configured)
> 	 and maintain a record of the publisher.
> 
>    Is this still valid? 

I think so.

> The changelog mentions that any publisher is now
>    allowed to delete items. Section 8.1.4 says:
> 
> 	 A service SHOULD allow publishers to delete items once they have been
> 	 published to a node that supports persistent items.
> 
>    Section 6 says:
> 
> 	 Pubsub servers MAY allow any publisher to delete any item once it has
> 	 been published to that node instead of allowing only the original
> 	 publisher to remove it.
> 
>    Do I understand correctly that an implementation may choose between:
> 
>      * Allow publishers to delete an item they published
>      * Allow publishers to delete any item 
>      * Disallow publishers to delete any items

The third option would obtain if the service did not implement deletion of
published items. If deletion is allowed at the service level, there are
two possibilities: (1) only the originating publisher is allowed to delete
an item, or (2) any publisher for that node is allowed to delete an item.
The JEP right now doesn't mention whether the choice between (1) and (2)
is a matter of node configuration or not, but that seems to make sense.

>    And, if this is indeed up to the implementation, does this need to be
>    discoverable and/or is it in the node configuration?

I think deletion of items is a service-level feature, and who is allowed
to delete items (originator or all publishers) is a node configuration
option.
 
>  - I assume the pubsub#persistent-items means:
> 
>    * Nodes at this service can be configured to be persistent 
>    * Items will in fact be stored when published

I *think* it's the first of these, because the second is a matter of node
configuration. But see below.
 
>    It does not mean items can be retrieved using <items/> (section
>    8.1.10) afterwards, so we need a feature for this too. My suggestion:
>    pubsub#retrieve-items.

I added that feature last night.
 
> 
>  - Maybe we should make it more explicit for each discoverable feature
>  what
>    is covered by it.

Agreed. I get a bit confused between service-level features and node-level
configuration. My understanding of the JEP is that the service discovery
features are reserved for service-level offerings or settings, and that to
determine if a node is deployed with a certain feature (e.g., ability to
retrieve items), you would need to request the node configuration rather
than send a service discovery request to the node. But perhaps this could
be clearer in the text.

>  - I assume the features are only returned when discoing the service
>  without
>    specifying a node.

I *think* so but the JEP author could clear this up for us. :-)

/psa






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