Re: lifetime of validators

    >>>   The change-indicator is used to indicate changes to the content of
    >>>   the resource uniquely identified by the Request-URI and variant-id.
    >>>   The change-indicator value SHOULD change when the content of an entity
    >>>   changes and SHOULD NOT change when the content remains the same.
    >>>   When the value changes, it MUST change to a value not already used for
    >>>   that entity within a timeframe for which there may still exist
    >>>   legitimately cached entities with the same change-indicator value.
    >> ...
> 
> At any rate, my compromise solution to this argument is to
> say nothing about it in the spec.  That is, the specification
> now says:
>     In order to be legal, a strong opaque validator MUST change
>     whenever the associated entity value changes in any way.  A weak
>     opaque validator SHOULD change whenever the associated entity value
>     changes in a semantically significant way.
> and says nothing about when the values can be reused or not.  Maybe
> we should include some "advice to implementors" about this later on.

That's too weak -- we definitely don't want people implementing just
a toggle and claiming compliance.  How about

   When the value changes, it SHOULD change to a value not already used for
   that entity within a reasonable timeframe for which there is likely
   to exist legitimately cached entities with the same change-indicator
   value.

Vague, yes, but at least it makes the point.

.....Roy

Received on Tuesday, 16 April 1996 22:35:33 UTC