W3C home > Mailing lists > Public > public-ldp@w3.org > November 2012

Re: LDP would benefit from being RESTful

From: (wrong string) čius <martynas@graphity.org>
Date: Wed, 14 Nov 2012 21:18:50 +0200
Message-ID: <CAE35Vmy_GKWrNe9VFLwqmY0CqHOL-fcuJpF_YQJSm4UdTCXdXw@mail.gmail.com>
To: Erik Wilde <dret@berkeley.edu>
Cc: Mark Baker <distobj@acm.org>, public-ldp@w3.org
Hey Erik,

good to see at least someone from the WG taking time to respond on
this rather inactive "official feedback channel".

> the problem with "making LDP RESTful" (according to the definition you refer
> to and the definition i was referring to above) is that RDF isn't RESTful it
> itself because it's not a hypermedia format. and we as a group cannot change
> this (it is way outside what we're chartered to do), this is just a
> limitation of the current state of affairs with RDF. this means that yes, we
> have to define vocabularies (as you say), but what we would need to do is
> define media types, which are a mix of data vocabularies (the
> representations) and interaction vocabularies (the affordances in
> representations provided by links). what you are asking us is to do this
> latter thing, and it would be great if we could do this, but unless we
> define our own framework for turning RDF into a hypermedia format, i have a
> hard time imagining how we could do it cleanly.

How is RDF any less of a hypermedia format than HTML? If it has
URIs/URLs built-in, you can follow them.

More importantly though, I would like to try to convince you that
there actually is a clean way to define this -- even a formal way.
To see it, we need to look at web application state. The current state
can be described with RDF, and restrictions for consistent state can
be expressed in OWL. Then, we need to look at HTTP as a mechanism for
changing that state (nothing new here).

We have state, we can change it, but it is currently undefined how.
What is missing in this picture is a state machine -- an explicit
definition of how any possible HTTP interaction changes the RDF state
so that it stays consistent within the restrictions. That way the LDP
specification could be formal, and visualized as a state chart, for

I tried to sum up this approach in a recent email, but it didn't get
any attention:

It doesn't even need any new vocabularies (well, almost -- a few
properties might be needed). Media types, base URIs, pagination etc do
not cause any problems in this approach.

If you think it makes sense, please pass this on to the WG.

Received on Wednesday, 14 November 2012 19:19:18 UTC

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