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Re: Weak and strong ETags

From: Henrik Nordstrom <hno@squid-cache.org>
Date: Fri, 01 Dec 2006 09:53:59 +0100
To: Wilfredo Sánchez Vega <wsanchez@wsanchez.net>
Cc: ietf-http-wg@w3.org
Message-Id: <1164963239.13050.10.camel@henriknordstrom.net>
tor 2006-11-30 klockan 20:03 -0800 skrev Wilfredo Sánchez Vega:

>    Two, I don't think you can assume that "X" and W/"X" are at all  
> related to each other.

HTTP specs do... see RFC2616 13.3.3, The weak comparison function.

> In Apache's case, there is no such guarantee,  
> because the same weak ETag may be issues to different versions of the  
> document (if it is edited more than once in the same 1-second window),  
> the data you got with an ETag of W/"X" may be completely different  
> than the data that later exists with an ETag of "X", or even the same  
> W/"X" you got.

Then Apache is somewhat broken.

Two identical weak etags SHOULD only be used if the objects is
semantically equivalent, but not necessarily octet equivalent. Two
different edits can not be considered semantically equivalent in this
context.  RFC 2616 13.3.4.

Regards
Henrik

Received on Friday, 1 December 2006 08:54:27 GMT

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