W3C home > Mailing lists > Public > ietf-http-wg@w3.org > October to December 2008

Proposal for issue #101 (strong/weak validators).

From: Yves Lafon <ylafon@w3.org>
Date: Fri, 14 Nov 2008 14:31:26 -0500 (EST)
To: ietf-http-wg@w3.org
Message-ID: <Pine.LNX.4.64.0811141428270.22460@ubzre.j3.bet>

Here is a proposed change for issue #101 [1], as the issue is more the 
definition of "weak validator", being linked to both unreliable 
identification of changes _and_ the will to signal only significant (read: 
semantic) changes.

In paragraph 5 of Part 4 [2], change:

    However, there might be cases when a server prefers to change the
    validator only on semantically significant changes, and not when
    insignificant aspects of the entity change.  A validator that does
    not always change when the resource changes is a "weak validator."

    Entity tags are normally "strong validators," but the protocol
    provides a mechanism to tag an entity tag as "weak."  One can think
    of a strong validator as one that changes whenever the bits of an
    entity changes, while a weak value changes whenever the meaning of an
    entity changes.  Alternatively, one can think of a strong validator
    as part of an identifier for a specific entity, while a weak
    validator is part of an identifier for a set of semantically
    equivalent entities.

=>

    However, there might be cases when a server prefers to change the
    validator only on semantically significant changes, and not when
    insignificant aspects of the entity change, or cases where the
    validator is use does not allow reliable identification of changes.
    A validator that does not always change when the resource changes
    is a "weak validator".

    Entity tags are normally "strong validators", but the protocol
    provides a mechanism to tag an entity tag as "weak".  One can think
    of a strong validator as one that changes whenever the bits of
    an entity changes, while a weak entity tag value changes whenever
    the meaning of an entity changes. Alternatively, one can think of
    a strong validator as part of an identifier for a specific entity,
    while an entity tag used as a weak validator is part of an identifier
    for a set of semantically equivalent entities.

Thoughts?

[1] <http://trac.tools.ietf.org/wg/httpbis/trac/ticket/101>
[2] <http://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-04#section-5>

-- 
Baroula que barouleras, au tiéu toujou t'entourneras.

         ~~Yves
Received on Friday, 14 November 2008 19:31:36 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 27 April 2012 06:50:57 GMT