Re: superimposing the Fielding and TBL architectures

On Tue, 2011-09-27 at 12:01 -0400, Jonathan Rees wrote:
> Mulling over designs for httpRange-14(a) opt-in, I made a picture
> (attached), just for fun, that superimposes the Fielding/3986
> architecture with the TimBL architecture.
> 
> What stands out is the common ground: There is general agreement on
> what constitutes a correct retrieval operation using a URI. The
> agreement derives from the RFCs and from server and client behavior.
> This is invariant as we modulate theories of what the resource is and
> what "is a representation of" means.
> 
> In the Fielding architecture the resource is unconstrained. I can give
> you a bunch of different resources, and then when you challenge me to
> prove that there is a resource with those Fielding-representations, I
> can cook up any story I like, post hoc, and you'd have no way to prove
> me wrong.
> 
> In Tim's architecture the resource is determined, modulo usually we
> probably don't care about, by what the correct retrieval results would
> be. Once those results are determined, there's no choice as to what
> the resource is. Contrariwise, if the server side commits to what the
> resource is, we can hold them to it by checking any
> TBL-representations that they deliver.

I don't know what you mean by saying "the resource is determined".  It
seems to me that the key difference (in this regard) between Tim's view
and Roy's is that Tim's view attempts to distinguish "information
resources" from other resources, and the "has TBL-representation"
relation only holds with information resources, whereas Roy's view has
no need for such a distinction: *any* resource can have a
wa:Representation.


> 
> httpRange-14(a) opt-in would be a statement or protocol element that
> says that the URI Fielding-identifies the generic resource (i.e. the
> same thing that it TBL-identifies).

But then what would be the difference between a wa:GenericResource and
an rfc3986-resource?  For example:

  :u a xsd:anyURI .
  :x a wa:GenericResource .
  :x :is-TBL-identified-by :u .
  :y a :rfc3986-resource .
  :y :is-rfc3986-identified-by :u .

What is the relationship between :x and :y ?  Are they the same thing?

And does there exist a :rfc3986-resource :z such that :z has a
3986-representation but :z is *not* a wa:GenericResource?  Or does the
mere existence of a 3986-representation imply that :z is a
wa:GenericResource?   (I.e., can there be a non-IR that has a
wa:Representation?)

My own view is that the existence of an authorized wa:Representation
implies that the resource is a wa:GenericResource (or IR).

David

> Nothing much new here, pretty much what Pat has said in different
> words (although I put less stock in "access" and more in social
> agreement over what would constitute correct access were it to occur).
> Just noodling.
> 
> Jonathan

-- 
David Booth, Ph.D.
http://dbooth.org/

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Received on Tuesday, 27 September 2011 16:56:51 UTC