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RE: ACTION-434: Some notes on organizing discussion on WebApps architecture

From: Larry Masinter <masinter@adobe.com>
Date: Mon, 18 Oct 2010 12:10:10 -0700
To: "Roy T. Fielding" <fielding@gbiv.com>
CC: John Kemp <john@jkemp.net>, "Appelquist, Daniel, VF-Group" <Daniel.Appelquist@vodafone.com>, "jar@creativecommons.org" <jar@creativecommons.org>, "www-tag@w3.org" <www-tag@w3.org>
Message-ID: <C68CB012D9182D408CED7B884F441D4D0476B4F38F@nambxv01a.corp.adobe.com>
We're trying to extend web architecture to talk about applications,
and the concepts/terminology we have seems to leave a gap, at least
for me. Just having "representation" and "resource" leaves me without
a way of talking easily about the relationship between

http://maps.google.com  and

http://maps.google.com/maps/place?cid=13506262960149713301&q=the+white+house&hl=en&ved=0CBAQhgUwAA&ei=nJm8TIfcB6i-jgO5_K2nBg&sig2=L4IeN4wW9YvHlGXDQkviKQ&sll=38.897096,-77.036545&sspn=0.020842,0.038418&ie=UTF8&ll=38.918017,-77.064199&spn=0,0&z=14&iwloc=A

Both of these URIs identify a "resource" which can have a
"representation", and possibly multiple representations,
which could vary based on the characteristics, capabilities
 and preferences of the receiver.

But what is the relationship of these two resources? I wanted
to suggest that the former (http://maps.google.com) is an
application, and the latter is also a resource, but it represents
an application state description.

In this case, the relationship between the URIs is reflected
in sharing an authority, although the latter adds path information
and query parameters.

In some cases, some of the application state can be communicated
in what we've been calling the "fragment identifier", because the
state is implemented on the client side rather than server side.

In the web applications world, a "document" can be thought of as
an application with limited functionality, namely, the function
of being able to present itself to the user, and the "state" of the
application is "scrolling the presentation to a particular part
of the document and/or selecting that part".

Larry
--
http://larry.masinter.net

-----Original Message-----
From: Roy T. Fielding [mailto:fielding@gbiv.com] 
Sent: Sunday, October 17, 2010 2:23 PM
To: Larry Masinter
Cc: John Kemp; Appelquist, Daniel, VF-Group; jar@creativecommons.org; www-tag@w3.org
Subject: Re: ACTION-434: Some notes on organizing discussion on WebApps architecture

On Oct 14, 2010, at 2:11 PM, Larry Masinter wrote:

> Well, I wonder if we might introduce another step between
> "resource" and "representation" which is "application resource
> in identified state", so that the representation isn't a
> representation of the resource, but a representation of the
> resource in that state.

Umm, what?  That would be terribly confusing and contrary to
why I used the term representation in the first place (it is a
representation by the origin server to the recipient of the state
of that identified resource at the time of message generation).

You might be thinking of the hypermedia workspace -- the state of
the user agent as it proceeds through an application, which may
include hundreds of representations in various states of modification
or use by the user agent.  Please don't confuse that with resource
state or representation -- it is neither of those.  There is a huge
architectural difference between what is known by the server (and
available to others as a resource) and the current state of one
user agent's workspace.  This is particularly important when the
application uses a special resource to store the workspace state
itself, such that it can be restored or shared with other devices.

....Roy
Received on Monday, 18 October 2010 19:11:12 GMT

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