Re: cache-busting document
Ben Laurie (ben@gonzo.ben.algroup.co.uk)
Sat, 7 Jun 1997 17:46:58 +0100 (BST)
Larry Masinter wrote:
> I've not seen any studies or reports that document the effect
> on effectiveness of caching for the HTTP/1.1 features that
> were added to support caching. Documenting the results would
> be very useful. It would be my guess that, after such documentation,
> you'd have more specific advice than 'use HTTP/1.1'.
Has anyone actually implemented an HTTP/1.1 cache yet? Certainly, Apache's
isn't. Sigh.
>
> > Use the Expires header on documents and images where feasible
> > - this will help caches to decide when your objects are stale.
>
> When is it feasible and when is it not? While we've conjectured
> the applications of Expires for sites that do dynamic content
> generation from static sources, for example, is that actually
> feasible?
Apache provides the facility (mod_expires).
> Do sites with planned expiration set expires dates?
Good question - this implies a level of planning I expect is largely absent
from the Web.
> Is it feasible to, for example, declare that '/images' at a site
> never changes (if you need to modify an image, give it
> a new name and change all the references), and then set it
> so that the embedded images never expire from caches even if
> the documents are dynamic?
Now this is a stunningly sensible suggestion. Changing all the references
would be onerous, though - unless it was done by server-side parsing (yech).
Cheers,
Ben.
--
Ben Laurie Phone: +44 (181) 994 6435 Email: ben@algroup.co.uk
Freelance Consultant and Fax: +44 (181) 994 6472
Technical Director URL: http://www.algroup.co.uk/Apache-SSL
A.L. Digital Ltd, Apache Group member (http://www.apache.org)
London, England. Apache-SSL author