Re: hotmail caching

Nottingham, Mark (Australia) wrote:

> Expires: [some time in the past]
> and:
> Cache-Control: max-age: 0
> or:
> Cache-Control: no-cache
>
> Expires catches the 1.0 caches; I believe max-age:0 is preferred, for some
> reason.

no-cache completely denies the cache to cache the objects.

max-age: 0 forces the cache to revalidate the object on next request.
Caching is allowed, but every request must be validated with the origin
server. If the server support object validations using conditional gets
then both caches and content providers are happy (object cached ->
bandwidth saved, server queried -> logs and hit metering correct, client
guaranteed to get the current version).

max-age is preferred over Expires since it is not plagued as much by
date inconsistensies and can be implemented at a date less HTTP server
(dates is not a strict requirement for HTTP servers, only proxies and
caches).

--
Henrik Nordstrom
Spare time Squid hacker