On 12/10/17 19:43, EdouardM wrote:
Amos, here is an example: http://au.download.windowsupdate.com/d/msdownload/update/software/updt/2017/09/windows10.0-kb4023814-x86_f07f9708c76807b1b19545521f17d6e2fefdd627.cab HTTP/1.1 200 OK Cache-Control: public,max-age=172800 Content-Length: 6150968 Content-Type: application/vnd.ms-cab-compressed Last-Modified: Wed, 27 Sep 2017 21:16:36 GMT Accept-Ranges: bytes ETag: "09295e6d537d31:0" Server: Microsoft-IIS/8.5 X-Powered-By: ASP.NET X-CID: 7 X-CCC: IN X-MSEdge-Ref: Ref A: 7A93444FAE0B4491BE72E049496DEC25 Ref B: BOM02EDGE0119 Ref C: 2017-10-12T06:36:40Z X-MSEdge-Ref-OriginShield: Ref A: C8FD899B17694B8AA6641257C2636B9B Ref B: BOM01EDGE0318 Ref C: 2017-10-11T14:02:56Z Date: Thu, 12 Oct 2017 06:36:40 GMT Length: 6150968 (5.9M) [application/vnd.ms-cab-compressed] does it mean the object will be valid for 2 days (max-age=172800) only, then the Squid will download a fresh copy from internet even if we set the refresh_pattern to 1 month ?
CC:max-age=172800 means it can be served unconditionally from cache for 172800 seconds from Date: Thu, 12 Oct 2017 06:36:40 GMT.
After Sat, 14 Oct 2017 06:36:40 GMT (Date + CC:max-age) it is stale and needs revalidating before any use. The headers from the revalidation response will alter the above headers to provide new values for Date and maybe other bits.
Altering Date naturally alters the base time for the max-age freshness calculation. So it should be served unconditionally for the next 48hrs from time of revalidation. Rinse and repeat. **
refresh_pattern is irrelevant here because all the necessary algorithm parameters for exact expiry (Date and CC:max-age) are provided by that server.
** NP: that is what should happen anyway, modulo bugs in Squid calculations or admin configuration settings to force other behaviour.
Amos _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
