Nginx: How to set headers for all the files under a specific folder

Question

So Let's say I have my application where files are under

https://myapp.com/v1/assets/images/*.jpg

and

https://myapp.com/v1/assets/js/*.jpg

I would like to add a rule that would set no-cache headers to anything under /assets

I believe what I can for now do is

 location ~ .*assets/js/.*$ {
  add_header Cache-Control "public, max-age=0, no-store";
}

location ~ .*assets/images/.*$ {
  add_header Cache-Control "public, max-age=0, no-store";
}

But that seems not working plus if I have many other folders under assets, I will need to add a separate rule.

Can I group everything in a pattern so that anything under /assets/* would have that header?

Thanks

Answer 1

This can be done via map directive:

map $uri $cache_control {
    ~/assets/(images|js)/    "no-cache, no-store, must-revalidate";
}
server {
    ...
    add_header Cache-Control $cache_control;
    ...
}

If your URI won't match the regex, $cache_control variable would have an empty value and nginx won't add that header to its response. However there are other nginx directives that could affect Cache-Control header, i.e. expires. If you have something like expires <value>; in your config, you can use two map blocks:

map $uri $cache_control {
    ~/assets/(images|js)/    "no-cache, no-store, must-revalidate";
}
map $uri $expire {
    ~/assets/(images|js)/    off;
    default                  <value>;
}
server {
    ...
    expires $expire;
    add_header Cache-Control $cache_control;
    ...
}

And take a look at this answer to not be surprised with add_header directive behavior.