How to set cache to never expire and minimize requests in Nginx?

Question

I have a cache invalidation system in place, so I need to set the cache for css|js to never expire.

I tried this

location ~* \.(js|css)$ { # |png|jpg|jpeg|gif|ico
  expires max;
  #log_not_found off; # what's this for?
}

And this is what I see in firebug:

So as you can see, requests are still being made, though they only receive a 'not modified' response. But I want to avoid them entirely, is that possible?

Also, I've read that an expirires of more than 1 year is or will be considered invalid in the standard. Is that true?

Edit

Let me complete @DisgruntledGoat's answer:

• Normal access to the url, like clicking on a link or in the url bar + enter: cache works, only 1 request issued for that url, and 0 for the assets.
• F5 to reload: many requests issued, but you receive all '304 not modified' responses for the assets, so they are not downloaded
• ctrl + F5 to reload without cache: many requests, all '200 success', all the assets are downloaded again.

Answer 1

Are you reloading the page to test this? When you do that, browsers generally request every file again (at least Chrome does). If you instead click links to different pages on your site, the browser should just use the cache and not re-request files.

Additionally, according to the spec the Expires directive can only have a date up one year in the future, so 2037 is an invalid value. Having said that, browsers generally accept far-future values just fine.

Answer 2

This cannot be done in another way you try it. It depends on the clients browser how cache is handled. Setting cache should not exceed one year more than the modification date Source.

Nginx is very effective, if you have < 1,000,000 visitors every day, you really don't have to worry about requests sent to Nginx. If it is about bandwidth, if a browser gets a 304 responce, it still uses the data from its cache, so no bandwidth is spilled.