W3C home > Mailing lists > Public > www-ws-arch@w3.org > December 2002

Re: Hypermedia vs. data (long)

From: Mark Baker <distobj@acm.org>
Date: Tue, 31 Dec 2002 15:16:42 -0500
To: Christopher B Ferris <chrisfer@us.ibm.com>
Cc: www-ws-arch@w3.org
Message-ID: <20021231151642.Z31971@www.markbaker.ca>

Whoa, long is right! 8-O

I'm gonna cut to the chase, if you don't mind.

On Tue, Dec 31, 2002 at 12:23:35PM -0500, Christopher B Ferris wrote:
> The user agent is not concerned with whether the text/html representation 
> of http://example.org/foo.html
> is a representation of a resource about human anatomy, politics, a 
> purchase order, or a description
> of my car. All it needs to "understand" is text/html (well, technically, 
> all it *really* needs to understand
> is text/* since it can simply display/render the received HTML document as 
> plain text and
> let the human do the understanding of the HTML tags and the content that 
> they markup).

For HTML, that's absolutely true.

But what if it were the "invoice" I described in my earlier example?
That's not HTML.  It has no stylesheet specified that would be able to
present it to a human.  It's meant *purely* for machine consumption.

To reiterate, what's the difference between;

GET <some-uri> returning some machine-processable XML document

and

POST <some-other-uri>
<envelope>
  <m:getInvoice/>
</envelope>

returning the same document?

In both cases, what is returned is the same, so the human/machine issue
is moot (which is why I'm not responding to your other points which are
trying to show a distinction).  The only consideration is how the data
got to the client in the first place, and I contend that the former is a
superior approach by any measure.

> It is my belief that what you are hearing from many of us is that REST 
> lacks a formal description
> capability because it assumes mostly that the user agents will be charged 
> with "understanding"
> but a few select media types and that "understanding" is limited to 
> rendering the representation,
> typically for consumption by a human.  I do not believe that you are 
> hearing us say "Links? We doan need no 
> steenkin' links":)

URIs and GET are a low-coordination-cost way of retrieving data.  There
is *NOTHING* human-specific about that.

MB
-- 
Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Web architecture consulting, technical reports, evaluation & analysis
Received on Tuesday, 31 December 2002 15:10:50 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Tuesday, 3 July 2007 12:25:11 GMT