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Re: Summing up on visibility(?)

From: Mark Baker <distobj@acm.org>
Date: Sun, 12 Jan 2003 00:41:11 -0500
To: Christopher B Ferris <chrisfer@us.ibm.com>
Cc: www-ws-arch@w3.org
Message-ID: <20030112004111.K5998@www.markbaker.ca>

(I know I said I wasn't going to continue, but Chris is asking good
questions here, so please excuse me)

Hi Chris,

On Thu, Jan 09, 2003 at 11:13:05PM -0500, Christopher B Ferris wrote:
> The one purpose that I think most people have for POST is the third use 
> case, would
> you not agree?

Yes, but I'm not sure agreement on that point counts for much. 8-) It's
been used to justify tunnelling before.  See;


> I should have been more clear... to be honest, it doesn't matter if they 
> are
> verbs or nouns. The intent that I had for the example was to illustrate 
> that
> in one case, you would POST a Review, say of a book, and in the other 
> case, you 
> would POST some feedback to the author of the book.

Sounds like nouns.  8-)

> Would you agree that that was a valid scenario and completely consistent 
> with
> the HTTP spec (and RESTful to boot)?

Absolutely.  A fine example.

> I'm not going for a priori in this case. I am trying to get you to agree
> that it is a perfectly valid and legitimate use of POST to have it 
> dispatch
> to separate handlers based on the type of entity body accompanying the 
> POST request.

Yes it is, except in the case of a method dispatch, because a method
dispatch is necessarily superfluous; if you've already dispatched on a
method, and then dispatch on another one somewhere else in the message,
then the dispatch on the first method was meaningless.

GET http://example.org/setValue?foo=3

If an HTTP intermediary saw that message, what does it mean to it?  It
means GET, that the message initiator is requesting a representation of
some resource be returned.  So if the service interprets that as a
request to set the value of foo to "3", then the intermediary was
fooled, i.e. a second method-dispatch occurred that made the meaning of
the message be something other than "GET".  That's how you get over
firewalls; don't try to fool them (aka don't tunnel).

If you only put nouns in that URI (which, since it's just an identifier,
makes sense), then the meaning of that message remains "GET".

> Not really because you didn't understand my example... Can we try again?
> (Sorry for not making it clearer before... It was certainly clear in my 
> head,
> just never made it to the electrons making up the ascii characters in my 
> note:)

No problem.  I should have asked you to clarify off-line.

Mark Baker.   Ottawa, Ontario, CANADA.        http://www.markbaker.ca
Web architecture consulting, technical reports, evaluation & analysis
Received on Sunday, 12 January 2003 00:40:57 UTC

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