RE: Expires and 'non-cacheable'

On Wed, 21 Jul 1999, Scott Lawrence wrote:

> > From: Nottingham, Mark (Australia)
> 
> > In 14.9.3,
> > [...]
> > Many HTTP/1.0 cache implementations will treat an Expires value
> > that is less
> > than or equal to the response Date value as being equivalent to the
> > Cache-Control response directive 'no-cache'. If an HTTP/1.1 cache receives
> > such a response, and the response does not include a Cache-Control header
> > field, it SHOULD consider the response to be non-cacheable in order to
> > retain compatibility with HTTP/1.0 servers.
> >
> > Would it be safe to assume 'non-cacheable' can be interpreted as 'stale'
> > here? (everything else says it is)
> 
> I usually use 'stale' to mean something that it was ok to cache for some
> amount of time, but that time has passed, so it is no longer ok to use the
> cached copy.  'non-cacheable' means that it should not get into the cache at
> all.

I agree ... 'non-cacheable' is supposed to preclude any possibility that
the data would be found in a cache and in particular a disk cache where
it might be examined. 'non-cacheable' is supposed to mean that it would
never be valid for a caching proxy to return in response to a request.
No second guessing, ever.

Dave Morris