giving rights to the creator of a resource

[bblfish]

In a recent discussion on access modes @justinwb brought up the use case that requires specifying the creators of a resource. I would like us here to think about how one can model a rule for this, assuming there is a way in Solid to specify the author of a resource.

In order not to get sidetracked into a discussion on how to specify who the author of a resource is, let us assume that we can just use the dublin core creator relation and that this would be easily available on the server, perhaps even in the headers, perhaps as the IANA author link relation. Clearly something like this is feasible, and being discussed in spec issue 315: Define Creator.

My question here is: how would one state in WAC or ACP or otherwise that all resources in a particular container can be edited only by their authors?

[bblfish]

It is always easiest to start with N3, as that gives us access to the full power of first order logic. I think I can express our rule like this:

{ ?i a foaf:Agent } => {
   [] a :Authorization;
     :accessToClass [ 
        a owl:Restriction;
        owl:onProperty iana:author
        owl:hasValue ?i ];
     :mode :Write;
     :agent ?i
}

This is telling us that we have one Authorization rule for each agent: namely given an agent i we have the authorization that gives that agent the Right to Write to the set of resources for which she is the creator.

In (advanced) Functional Programming languages I think these would be represented as dependent types. A way of presenting a dependent type is often as a sheaf over a function and is illustrated with an image such as the following (see my blog post Modal HoTT on the Web).

In that picture we would have the Set A be resources, the Set I below that be Individual agents, and a function going from top down createdBy: A → I taking resources to the agents that created them. If we then take any individual i ∈ I and go the other direction we have a set of resources associated with every agent, like a stalk of resources over every agent. Those would be the little Ak, Aj, ... in the picture. So really we have one little rule associating every agent to a set of things it created. In N3 we can express this as a rule. That should be ok, because the agent in the rule can be filled out when the request is being made.