Re: clarifying containment vs membership

On Wed, Feb 19, 2014 at 12:18 PM, Sandro Hawke <sandro@w3.org> wrote:

>  As I read the spec, it seems to me that normally a container contains
> exactly the same resources it has as members.
>
> The one circumstance I can see where this would not be true is when
> ldp:insertedContentRelation is used.
>
> I think this is reasonable, but I'm not at all sure I'm reading things
> right.  Is there some other circumstance where it's possible to have a
> resource that is a member but is not contained, or is contained but is not
> a member?
>

They way the resolution was, for any resource created in a container, the
triple (ldpc, ldp:contains, ldpr) must be present.  In other words, only an
administrator of the server who knows what she is doing can mess with these
triples directly.  Servers shouldn't allow PUT/PATCH from clients on them.

Membership triples are a bit weaker.  Like the creation case above but in
addition, a membership triple is created.   Membership triples could be
PATCHed (I guess PUTting them isn't the end of the world either) to add or
remove them.  Membership triples form can be thought of as typically
managed by container operations but clients can adjust them later.


> (I guess the current spec doesn't rule out the server making these sets
> different for its own reasons, but I think the clients can't make it
> happen, so I'm not too worried about it.   It would probably be best if
> servers were forbidden from doing it, too.)
>

I think for a certain class of servers, they will typically be the same.
 Though for others that support some concepts like a view over resources or
references to resources the server has no authority over, then membership
triples that are independently managed by the client is another class of
LDP servers.

I attempted to capture the resolution without having to rewrite the entire
spec.  If you can highlight portions the seem to conflict or need
elaboration, always appreciated.

- Steve


>
> BTW, I have an alternative proposal for ldp:insertedContentRelation (which
> I think has some problems), but I want to make sure I understand the
> context before I get into that.
>
>          -- Sandro
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