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Re: REST; good for humans and machines

From: Mark Baker <distobj@acm.org>
Date: Sun, 5 Jan 2003 13:57:32 -0500
To: "Champion, Mike" <Mike.Champion@SoftwareAG-USA.com>
Cc: www-ws-arch@w3.org
Message-ID: <20030105135732.S12258@www.markbaker.ca>

On Sun, Jan 05, 2003 at 10:46:45AM -0700, Champion, Mike wrote:
> So, I'll clarify what I said earlier:  If the representations being passed
> around are being processed by humans, the REST interfaces are sufficient --
> they just have to deliver the information, and the human reads it (or fills
> out the form, or finds an appropriate hyperlink, or whatever).

Wait a sec, Roy said that REST is suitable for automata.  That means no
humans are required in the loop.  Did he not make that clear?

> I just can't get worked up over the
> distinction between POSTing a getLastSharePriceOfIBM message and GETing a
> http://www.stockquotes.com/ibm/lastshareprice resource. There are advantages
> and disadvantages of both -- the former is easier to automate, leverages XML
> more readily, avoids URI encoding issues ... the latter is hyperlinkable,
> cacheable, more easily integrated with the human-oriented web, etc.  I take
> the rather quixotic job of replying to this permathread because I'd love to
> see a detailed enumeration of the advantages and disadvantages so that we
> can put them in the WSA document. 

There's only one point in this enumeration that matters when it comes to
working across trust boundaries; late binding via a coordination
language.

So I'll give you +1 for "leverages XML" for getLastSharePriceOfIBM, but
-1000 for not being late bound.  That's the magnitude of the
archtectural implications we're talking about here, and what I mean by
"low coordination costs"; fundamentally, with REST and other Internet
scale architectural styles, you're agreeing on higher level stuff up
front, so things are made easier at runtime.

Can you not see how much easier it is to coordinate the communication
of information between untrusted parties with URIs and GET?  Or do you
see it, but don't feel that the difference matters?  An answer to that
would help me focus my responses.

MB
-- 
Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Web architecture consulting, technical reports, evaluation & analysis
Received on Sunday, 5 January 2003 13:57:11 GMT

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