On Wed, 19 Oct 2005, Henrik Nordstrom wrote:
Vary and PURGE is a complicated combination.. you need to issue PURGE
requests of each unique combination seen of the Vary listed headers. This is
complete headers as sent by the clients, not just the pieces the web server
actually cares about..
If you don't you only purge Squids knowledge of that this object varies, and
the next request will rebuild this knowledge.
A crazy idea, but to get around this oddness of the Vary support in
Squid-2.5 you could include a custom header in your Vary header on the
form
X-change-NNNN
where NNNN is a unique identifier of the last change of the document. By
changing this number after an update any older cached entity will be
forgotten by the cache.
This header does not need to be present anywhere except for the Vary
header.
A better alternative is probably to look into using the ETag patch
available from devel.squid-cache.org. This makes the Vary support in
Squid-2.5 much saner, especially if your server is supporting
"If-None-Match".
Regards
Henrik
