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Comments about http://www.w3.org/DesignIssues/Architecture#Conten t : is GET the only idempotent method

From: Mike Dierken <mike@dataconcert.com>
Date: Thu, 10 Jan 2002 12:53:06 -0800
Message-ID: <2AE31649CF989F4FB354F6D95EB0CE6E4D6745@xmlfmail.xmlfund.com>
To: www-tag@w3.org

"The introduction of any other method apart from GET which is idempotent is
also incorrect, because the results of such an operation effectively form a
separate address space, which violates the universality."

I though that PUT was idempotent - it is okay to do the same PUT twice
without bad stuff happening.

"As HTTP is a state coordination language, even if my PUT
request lost the connection after the PUT was performed, I have choices.
I can check the state of the thermostat with a GET to see if it's set to
21C, or I can re-invoke the PUT, which works because PUT is idempotent."

From Mark Baker in private mail:
"Idempotent just means that 'the side-effects of N > 0 identical requests is
the same as for a single request'.  So if you didn't know whether PUT worked
or not, you could do it again without fear."

If there is too much noise from non-members (i.e. me) on this mailing list,
I'll make my comments privately to a member(s) first.

> -----Original Message-----
> From: Tim Berners-Lee [mailto:timbl@w3.org] 
> Sent: Thursday, January 10, 2002 11:48 AM
> To: www-tag@w3.org
> Subject: Re: [Minutes] 7 Jan 2002 TAG teleconference
> > The Chair also asked participants to review the early 
> sections of Tim 
> > Berners-Lee's "Web Architecture from 50,000 feet": 
> > http://www.w3.org/DesignIssues/Architecture
> and http://www.w3.org/DesignIssues/Axioms
Received on Thursday, 10 January 2002 15:54:03 UTC

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