cache-control immutable

I am no expert but I see immutable on everything now. I believe adding cache-control immutable would improve performance. Apparently even with max age set, browsers will revalidate on a page reload and immutable helps stop that from happening: https://www.keycdn.com/blog/cache-control-immutable

Expected behaviour

responses should be cache-control: max-age=31536000,public,immutable

Actual behaviour

responses are cache-control: max-age=31536000,public

I don’t think there is any harm in setting it if public and max-age > 0.

[kkopachev]

This seems like a useful feature.

[Enalmada]

@caeugusmao Thanks for the nginx tip. I think that is a great suggestion for everyone until it it is officially supported. I am adding it using the following commands:

   proxy_hide_header Cache-Control;
   add_header Cache-Control "public, max-age=31536000, immutable";

(I am no nginx expert and there is likely a better way to append immutable to the existing header but I found it easiest to hide the current one and add the new one to avoid duplicate)

Yes, if it is something you would want I will send a PR eventually. I wouldn’t be sad if one of you beat me to adding the “, immutable” to the cache string if you happen to be in the code area though.