1. proxy_cache_valid is set to 1h and upstream's response is valid for 2h.
nginx will cache for 2h.
2. proxy_cache_valid is set to 2h and upstream's response is valid for 1h.
nginx will cache for 1h.
3. proxy_cache_valid is set to 1h and upstream's response doesn't
contain any caching hints.
nginx will cache for 1h.
This just means that upstream's caching instructions are more
important than proxy_cache_valid, right?
What happens if the client sends "If-Modified-Since" header?
This header does not send to backend, however, nginx may responses 304.
I'm not sure if I understand. Let's imagine some scenarios (I-M-S
stands for If-Modified-Since, L-M stands for Last-Modified):
1. Client sends I-M-S, Nginx has response in cache, cached response
has L-M < I-M-S, Nginx sends 304.
2. Client sends I-M-S, Nginx has response in cache, cached response
has L-M > I-M-S, Nginx serves response from cache.
3. Client sends I-M-S, Nginx doesn't have response in cache, sends
request to upstream, upstream's L-M < I-M-S, Nginx stores response in
cache and sends 304.
4. Client sends I-M-S, Nginx doesn't have response in cache, sends
request to upstream, upstream's L-M > I-M-S, Nginx stores response in
cache and sends response from upstream.
Am I right?
Regards,
4 messages in ru.sysoev.nginxRe: proxy cache
