NGINX Cookbook

How it works...

NGINX internally tracks the status of the request ($upstream_cache_status), so by exposing it as a header, we can now see it from the client side. If we use Google DevTools or a utility such as httpstat to see the headers, you should see an output like this:

httpstat http://proxy.nginxcookbook.com/ 
 
HTTP/1.1 200 OK 
Server: nginx/1.11.2 
Date: Sun, 09 Oct 2016 12:18:54 GMT 
Content-Type: text/html; charset=UTF-8 
Transfer-Encoding: chunked 
Connection: keep-alive 
Vary: Accept-Encoding 
X-Powered-By: PHP/7.0.12 
X-Cache-Status: HIT 

We can see by the X-Cache-Status header that the request was a hit, meaning it was served from the cache not the backend. Other than the basic hit and miss, there are also a number of other statuses which ...