How to check if a file is cached or not cached?
In UNIX based systems you can use "curl -I [url]" to check your file headers.
curl -I http://cdn77.www.cdn77.com/js/intlTelInput/css/intlTelInput.css
HTTP/1.1 200 OK
Date: Tue, 18 Nov 2014 15:28:36 GMT
Last-Modified: Wed, 16 Jul 2014 08:51:22 GMT
X-Edge-Location: Prague, CZ
That means http://cdn77.www.cdn77.com/js/intlTelInput/css/intlTelInput.css isn't cached, because of "X-Cache: MISS" value. If you repeat the command and the result will be X-Cache: HIT, it means the file was cached in the CDN PoP. However if you see "X-Cache: MISS" after several tests, it means the file will not be cached in the CDN PoP at all. In that case, you will need to check the setting of the cache control header.
Examples of possible headers which restrict cache settings:
Cache-Control: max-age=600 - the file will be cached for 600 seconds
Cache-Control: no-cache or Cache-Control: max-age=0 - the file will never be cached in our CDN PoP
How to set them? Look on our article.