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Re: Idempotent partial updates

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 28 Feb 2012 17:49:38 +0100
Message-ID: <4F4D05A2.4000907@gmx.de>
To: Martin Thomson <martin.thomson@gmail.com>
CC: Mike Kelly <mikekelly321@gmail.com>, HTTP Working Group <ietf-http-wg@w3.org>
On 2012-02-28 17:30, Martin Thomson wrote:
> On 28 February 2012 00:37, Julian Reschke<julian.reschke@gmx.de>  wrote:
>> How exactly is it "not visible"?
>>
>> "A PATCH request can be issued in such a way as to be idempotent, [...]
>
> "Can be" not "is".  You can issue a non-idempotent PATCH.  Though you
> are advised not to, it is possible.  Therefore, an intermediary cannot
> assume that the request is safe to retry.

It can, if it comes with If-Match. Or am I missing something?

> A PUT is by definition idempotent.  A PATCH, like POST, is only
> idempotent under (secret, non-obvious) conditions.

That is true, but I'm not sure that is a problem when the conditions are 
well understood and documented.

Best regards, Julian
Received on Tuesday, 28 February 2012 16:50:18 GMT

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