Hi everyone,
Here is my understanding on http cache.
1. UserA request a new resource
2. Squid cannot find in cache,request to original server
3. Original server response with Last_Modified and expires ,say 10
minutes
4. Squid cache the response and reply to UserA
5. UserA 's agent won't send another request to same url in 10 minutes.
6. After 2 minutes,UserB send a request to squid (Same url of course)
7. Squid response UserB using the cached content, It don't send request
to original server
8. UserB 's agent won't send another request to same url in 8 minutes.
9. Hours later (No other request)......................
10. UserA revisit this url,his agent send a request with
If_modified_since
11. Squid found in cache, but need validate. So it send a request with
If_modified_since to original server
12. original server response with 304,not modified. and add a http
header
control expires to now+10mintes.
13. Would squid update the expires information?
14. After 2 minutes,UserC send a request to squid
15. squid would validate the request or not?
16. The response squid reply to UserC,when will expires? or within the
following 8 minutes,UserC's agent will send more request ?
Thanks!
Baily
