Re: Containers and membership subject/object asymmetry

Steve,

I think it can be done this way:

[[[
PUT /steves/friends HTTP/1.1
Host: example.org
Content-Type: text/turtle

@prefix foaf: <http://xmlns.com/foaf/0.1/>.
<http://example.org/steves#me> foaf:knows <http://example.org/richard#me>.
]]]

I believe that the members of LDPCs can be arbitrary RDF terms, including literals and non-LDPR URIs (e.g., hash URIs).

It's probably true that you can't do this with POST. Is that a problem? (I think it's not a problem with the example you've chosen, because the documents for Steve and Richard will not be created through a �friend� container but through some �all personal profiles� container.)

In my mind, the kind of container that creates new resources through POST is only for containers that have �collection of documents� semantics. A collection of friends is different.

Best,
Richard


On 20 Mar 2013, at 15:31, Steve Battle <steve.battle@sysemia.co.uk> wrote:

> I'm experiencing mild anxiety about containers and membership subject/object asymmetry. Consider the Steve's friends example.
>  
> Consider an LDPR representing Steve foaf profile <http://example.org/steves>:
>  
> <> a ldp:Resource, foaf:PersonalProfileDocument ;
>                 foaf:primaryTopic <#me> .
>  
> <#me> a foaf:Person ;
>                 foaf:name "Steve" ;
>                 foaf:nick "SteveS" .
>                
> And another LDPR representing Richard's foaf profile <http://example.org/cygri>:
>  
> <> a ldp:Resource, foaf:PersonalProfileDocument ;
>                 foaf:primaryTopic <#me> .
>  
> <#me> a foaf:Person ;
>                 foaf:name "Richard" ;
>                 foaf:nick "cygri" .
>                
> To represent Steve's friends, I'll create a container <http://example.org/steves/friends>. Note that the membership subject is not the container, nor the LDPR for SteveS, but the hash URI representing Steve himself, because the subject of the 'knows' predicate is a Person rather than a document. Now I want to assert that Steve knows Richard as defined below. Note that the object of 'knows' is also a Person.
>  
> <> a ldp:Container ;
>                 ldp:membershipSubject foaf:knows ;
>                 ldp:membershipSubject <http://example.org/steves#me> .
>                
> <http://example.org/steves#me> foaf:knows <http://example.org/richard#me> .
>  
> Here comes the asymmetry; while I can use a hash URI as the membership subject, I can't see how I can construct the above reference to the member hash URI <http://example.org/richard#me> using POST. Could we allow a URL to be POSTed (with an empty body) to a container via Content-Location? Is this perhaps something along the lines that Roger Menday was asking for (atomic operations)?
>  
> Thoughts?
>  
> Steve.

Received on Wednesday, 20 March 2013 16:25:17 UTC