Re: What is The logic of Vary Headers cachiness?

On 07/24/2013 11:23 PM, Amos Jeffries wrote:
>>> To complicate matters further different responses MAY have different
>>> Vary header value. But it is not very likely.
>> True. To support that, we would need to add a list of Vary header values
>> to the special Vary object and iterate it, looking up a cache object for
>> every listed Vary header value.
>
> We think alike. See my other reply. Although the lookup per-match is not
> required. HTTP only requires that we identify a whole set of options and
> pull the most appropriate - with some requirements around defining
> "appropriate".

Yes, my "every listed" phrasing was wrong.

Only one extra lookup may be needed in most cases, but since we live in
SMP world, there are no guarantees that the variant listed in
x-vary-marker object is still cached. Thus, we need to iterate the list,
find the first (or best) "appropriate" candidate, look it up, and either
terminate the search (on lookup success) or keep going in hope to find
another "appropriate" candidate (on lookup failure).

Cheers,

Alex.
Received on Thu Jul 25 2013 - 15:44:34 MDT