Caching for Error Pages

Sometimes clients will notice that their error pages are being cached. Say one of their files was missing from the origin, and they re-uploaded it, but CDN is still returning their 404 page until the cache is fully purged. The reason behind this is that the 404 page happened to have a Cache Control Header. In the example below, a 404 page with a CCH which will be cached.

$ curl -I http://foobar.example.com/myimages/some_random_image.png
HTTP/1.1 404 Not Found
Server: nginx/1.0.11
Date: Thu, 26 Jan 2012 20:01:36 GMT
Content-Type: text/html;charset=utf-8
Connection: keep-alive
<strong>Cache-Control: public, max-age=24383317
Expires: Tue, 06 Dec 2012 17:33:42 GMT
Last-Modified: Sat, 01 Jan 2000 00:00:00 GMT</strong>
Content-Length: 1051

$ curl -I http://foobar.example.com/myimages/some_random_image.png

HTTP/1.1 404 Not Found

Server: nginx/1.0.11

Date: Thu, 26 Jan 2012 20:01:36 GMT

Content-Type: text/html;charset=utf-8

Connection: keep-alive

<strong>Cache-Control: public, max-age=24383317

Expires: Tue, 06 Dec 2012 17:33:42 GMT

Last-Modified: Sat, 01 Jan 2000 00:00:00 GMT</strong>

Content-Length: 1051

These bolded headers should not exist with error pages, otherwise NginX will cache the error page as if it is a valid page.

Please make sure to unset/remove all headers on your 404/Error pages. Or if not possible, set a no-cache header as explained below, and as explained in this article.

    ExpiresDefault A0
    Header set Cache-Control &quot;no-store, no-cache, must-revalidate, max-age=0&quot;
    Header set Pragma &quot;no-cache&quot;

ExpiresDefault A0

Header set Cache-Control "no-store, no-cache, must-revalidate, max-age=0"

Header set Pragma "no-cache"