15. no-cache + ETag
Client Server
GET
200 OK
Cache-Control →no-cache, private
ETag →“123"
...
GET
If-None-Match→“123"
Checking
cache
304 Not Modified
16. no-cache + Last-Modified
Client Server
GET
200 OK
Cache-Control →no-cache, publice
Last-Modified→ Sat, 01 Jan 2000 00:00:00 GMT
...
GET
If-Modified-Since → Sat, 01 Jan 2000 00:00:00 GMT
Checking
cache
304 Not Modified