Undefined HTTP response caching through Nginx fails

Question

I am trying to tell nginx to cache some of my assets (js, css) forever, or at least for a very long time.

The idea is that as soon as the asset package is compiled and published with the URI prefix /assets/(for example /assets/foo-{fingerprint}.js), it remains there and does not need to be changed.

The internet told me that I should write the following rule:

location ~ ^/assets/.*-([^.]+)\.(js|css)$ {
  gzip_static on; # there also a .gz of the asset
  expires max;
  add_header Cache-Control public;
  add_header Last-Modified "";
  add_header ETag "";
  break;
}

I expect this to lead to responses with HTTP code 304 "Not Modified", but I get a consistent HTTP 200 (OK) every time.

I tried some other approaches, for example:

a) by explicitly setting the modification time to a constant point in time in the past;

add_header Last-Modified "Thu, 01 Jan 1970 00:00:00 GMT";

b) transition to verification If-None-Match;

add_header ETag $1;
if_modified_since off;

, , :

add_header Last-Modified "Thu, 01 Jan 2030 00:00:00 GMT";
if_modified_since before;

. , . , .

Answer 1

, .

add_header ( brake):

location ~ ^/assets/.*-([^.]+)\.(js|css)$ {
   gzip_static on; # there also a .gz of the asset
   expires max;
}

: http://nginx.org/r/expires http://tools.ietf.org/html/rfc2616

Answer 2

. , ConditionalGet (E-Tag, Last-Modified). , , .

(js, css, images) , - . , , - .

:

add_header Cache-Control public;
add_header Last-Modified "";
add_header ETag "";