Cascading Caches, honor Age Header

[C. Handel]

Hi,

When i cascade varnish in front of a squid (didn't test varnish in
front of varnish) it won't honor the Age Header sent from the squid.

If the Squid sends me

Age: 100
Date: Fri, 06 Jul 2007 11:08:20 GMT
Expires: Fri, 06 Jul 2007 11:13:20 GMT

varnish should start with an initial Age of 100. This way i could keep
the expiration of multiple varnish instances in sync.

it might be possible to use the new features mentioned in "New VCL
toys". So after fetching a object from the backend, before storing it
i could

set obj.age = now - obj.date

supposing the time on varnish and backend server is in sync.



Greetings
  Christoph