I have a website with some images sent from php script. Every time ETag is sent and checked with next request. That works fine. On first page open all files are downloaded with 200 Ok and with the next with 304 Not Modified.
But I noticed that some file sent directly from http server are event not checked for beeing modified if I re-open the page but are while reloading (F5).
If I open the page for the first time:
Files from web server: 200 Ok
Files from php script: 200 Ok
If I press F5:
Files from web server: 304 Not Modified
Files from php script: 304 Not Modified
If I reopen the page:
Files from web server: NO REQUEST
Files from php script: 304 Not Modified
What I want to do is to make browser skip checking whether my files where modified or not and display the cached version. So I checked respones that http and php script are sending to browser:
Static content from http server:
Accept-Ranges bytes
Connection keep-alive
Content-Length 22033
Content-Type image/png
Date Sat, 15 Mar 2014 10:42:06 GMT
Etag "523c1617-5611"
Last-Modified Fri, 20 Sep 2013 09:32:07 GMT
Server nginx
Content served by php script:
Connection keep-alive
Content-Type image/jpeg
Date Sat, 15 Mar 2014 10:45:16 GMT
Etag c4ca4238a0b923820dcc509a6f75849b
Server nginx
Transfer-Encoding chunked
So the differences are:
Accept-Ranges, Content-Length, Last-Modified, Transfer-Encoding
But the only one which I THINK could make browser not check for update is Last-Modified. So if I add Last-Modified to my php script - would browser skip checking for update?
