Static caching via expires and asset timestamps

To speed up page loading, you can set the expires header far into the future for static components.
However, there is one problem: you will have to change the file name or the path to it so that the user knows that the file needs to be re-read.

In Rails, there is a useful opportunity for assets timestamps , to be honest, I did not understand why this was necessary before.

Let's figure it out?
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In order not to repeat, I will give a link to the article with a detailed description of the logic: Configure the Expires header for Rails under nginx

The general meaning is as follows:

• if we insert all static into templates through rails helpers, then Rails in production will add to them so-called assets timestamps. Roughly speaking it:
  File.mtime(path).to_i.to_s # rails_asset_id

• when the file is changed, the path to it will change, respectively, and the client browser will send the request again
• it is necessary to make the web server install all static files that have assets timestamps Expires header c far in the future time:
  
  • nginx, ngx_http_headers_module
    

     if ($ request_uri ~ * "\. (ico | css | js | gif | jpe? g | png) \? [0-9] + $") {
         expires max;
         break;
     }
    

    
    
  • httpd, mod_expires
    

     ExpiresDefault "access plus 1 year"
    

  
  
• It remains only to check with the help of YSlow that our configuration works.

UPD: Example in real config gist.github.com/14614