Re: Expires: headers for Packages.gz, Sources.gz

[Jason Gunthorpe <jgg@debian.org>]

On Sat, 10 Feb 2001, Matt Zimmerman wrote:

> > > to the appropriate config block(s).  This would allow caches to be very
> > > accurate about the freshness of their copies of these files.
> > 
> > You do know that APT already sends the client side version of this header
> > that forces an IMS check on the proxy .. 
> 
> Yes, but Squid (for example) will not forward an IMS request to the server if
> the cached object is fresh.

Then it is in violation of RFC2068, secion 14.9:

   The Cache-Control general-header field is used to specify directives
   that MUST be obeyed by all caching mechanisms along the
   request/response chain.
[..]
   max-age
     Indicates that the client is willing to accept a response whose age
     is no greater than the specified time in seconds. Unless max-stale
     directive is also included, the client is not willing to accept a
     stale response.

Which is the header APT sends, with a 1 day old setting by default. If you
set that to 0 say (there is a configuration setting), then squid is
required to never return a non-validated response.

Jason