> Matus UHLAR - fantomas wrote: > >you set up images to expire after a month, and wonder that they don't > >expire > >before a month? On 21.12.08 09:33, Tom Williams wrote: > As strange as that sounds, basically yes. :) The reason I set the > expiration period for one month is I don't expect the images to change > frequently at all. However, if the image DOES change at some point > within that month time period, I would want the image to be refreshed. Don't send Expires then. Expires means that the object will NOT be re-fetched. I think using "Cache-Control: must-revalidate" header should be enough. > I'm sure my understanding of this is wrong but I was thinking if I set > the images to expire after say one day or one week, Squid would purge > the image that was in the cache and request an updated copy of the > image. > If the image isn't changing with much frequency, I wouldn't want > Squid to fetch a "fresh", yet unchanged, copy of the image with much > frequency. Since I set the expiration to be since the image was last > modified, I was thinking Squid would ask the server if the image had > changed and fetch a new copy if it did. If the image had not changed, > after a month it would purge the old image and fetch a new one. Now > that I've written that, that doesn't make much sense either. > > So, how do the expires headers impact Squid's interaction with the web > server in a reverse proxy configuration? I think you should read RFC2616 (HTTP/1.1) for description of Expires and Cache-Control headers. They together can be used to fine-tune caching behaviour on caching proxy servers. The Expires: header just does not what you want. -- Matus UHLAR - fantomas, uhlar@xxxxxxxxxxx ; http://www.fantomas.sk/ Warning: I wish NOT to receive e-mail advertising to this address. Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu. 10 GOTO 10 : REM (C) Bill Gates 1998, All Rights Reserved!
