If you’ve got anything to do with Akamai’s caching, surely there must have come a time where you needed to find out whether your content is being cached at Akamai.
The easiest way to test whether your content is cached at Akamai is to do via custom Pragma headers. What are Pragma headers you might say? The HTTP Specification has a simple definition of Pragma headers.
The Pragma general-header field is used to include implementation-specific directives that might apply to any recipient along the request/response chain. All pragma directives specify optional behavior from the viewpoint of the protocol.
In short, Pragma headers specific cache headers1 that are can be used by any party in the entire chain from request-response (in our case Akamai) to communicate specific caching functionality.
Here’s how you can do it -
~ curl -H "Pragma: akamai-x-cache-on" -H "Pragma: akamai-x-check-cacheable" -I "http://static.xcite.com/skin/frontend/orange/default/images/xcite_logo.png" HTTP/1.1 200 OK Server: nginx/0.8.55 Content-Type: image/png Last-Modified: Sun, 02 Feb 2014 00:29:51 GMT ETag: "26d8eb2-1c43-4f16181581dc0" Accept-Ranges: bytes Content-Length: 7235 Cache-Control: max-age=2142389 Expires: Tue, 04 Mar 2014 04:06:26 GMT Date: Fri, 07 Feb 2014 08:59:57 GMT Connection: keep-alive X-Cache: TCP_MEM_HIT from a168-187-253-133 (AkamaiGHost/6.14.4-12151432) (-) X-Check-Cacheable: YES
In the above curl request we are sending Akamai Specific Pragma headers to fetch a static
png file from a URL that is on Akamai. The two key response headers that important here are the last two
X-Check-Cacheable. Below is a curl request to a asset which is not cached by Akamai.
~ curl -H "Pragma: akamai-x-cache-on" -H "Pragma: akamai-x-check-cacheable" -I "http://www.xcite.com" HTTP/1.1 200 OK Server: nginx/0.8.55 Content-Type: text/html; charset=UTF-8 Expires: Thu, 19 Nov 1981 08:52:00 GMT Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Pragma: no-cache X-Served-By: 381172-web1 1.0-1549 X-Frame-Options: sameorigin Date: Fri, 07 Feb 2014 09:09:22 GMT Set-Cookie: frontend=kbpnphh3o3ohbmvu9j83ioigv6; expires=Fri, 07-Feb-2014 10:09:21 GMT; path=/; domain=.xcite.com; HttpOnly X-Cache: TCP_MISS from a217-243-192-27.deploy.akamaitechnologies.com (AkamaiGHost/220.127.116.11-12122608) (-) X-Check-Cacheable: NO
As you can see,
X-Check-Cacheable here is
NO which indicates that content is not cached on Akamai.
I just used 2 pragma headers for testing, there are few others pragma headers that you can use to get even more information
See you next time!