Re: superimposing the Fielding and TBL architectures

OK, a few points. 

1. This diagram suggests that the two resources must be different, but they could be the same thing (I believe...). 
2. The diagram glosses over what I think is (and always has been) the key issue, which is that TBL-representation has no single meaning: sometimes it means 'denotes' and sometimes it means 3986-representation, although...
3. ... nobody has ever, AFAIK, given a clear unambiguous account of what 3986-representation actually means. 
4. When TBL-representation means denotation, TBL-identifies is meaningless, so the diagram kind of breaks at that point. 
5. What is the wa:Representation a representation of? And in what sense of 'representation'?

On Sep 27, 2011, at 11:01 AM, 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.

Sure, but not on the status of what is actually retrieved, or how it relates to the 'identified' resource. 

> 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.

I dont think so. The representation in that loop must be something that can be a retrieval result and must also record the current state of the resource. So the 3986-resource must be something that has states which can be recorded in a representation which can be retrieved over a network. That rules out, for example, distant galaxies (too big), sodium atoms (too small) and fictional or abstract entities (no state). In practice it also rules out things like the weather in Oaxcala, actually. Maybe you can refer to this state and describe it, but you can't *record* it. 

Pat

> 
> 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.
> 
> 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).
> 
> 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
> <gr.png>

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Received on Tuesday, 27 September 2011 18:05:09 UTC