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Re: Globally unique e-tags, if-match on content-ID, etc.

From: Koen Holtman <koen@win.tue.nl>
Date: Mon, 15 Sep 1997 21:38:42 +0200 (MET DST)
Message-Id: <199709151938.VAA14673@wsooti08.win.tue.nl>
To: Larry Masinter <masinter@parc.xerox.com>
Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Larry Masinter:
>
>One of the technical issues that came up in recent discussions
>about "Push" technology is the usefulness, for some applications,
>for a globally unique content-ID. While "content-ID" might be
>a useful header in a response, there's no corresponding request
>header, since the etag is only guaranteed unique relative to 
>the given URL.
>
>Can 'if-match' be extended to use content-IDs as well as
>ETags? Or, can we add some space of 'globally unique etags'?

HTTP/1.1 does not require an ETag to be globally unique, but it does
not forbid it either.  If it wants to, the server can simply put its
globally unique entity identifier in the Etag header, adding another
header which basically says `the etag in this response is also a
globally unique identifier'.  There is no need to extend if-match,
if-none-match, and if-range, they would keep working as is.

>Larry

Koen.
Received on Monday, 15 September 1997 12:44:44 EDT

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