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onassar
Asked: 2014-09-09 10:35:49 +0800 CST

Having trouble removing HTTP header "Cache-control"

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I'm trying to get my assets cached using Cloudflare
Cloudflare states here that "CloudFlare will not cache your site or static content if you have no-cache and private headers coming from your server"

As you can see from my file response, Cache-control: no-cache="set-cookie" is coming through:
https://redbot.org/?uri=http%3A%2F%2Fdev.shareasimage.com%2Fstatic%2Fapp%2Fimages%2Fads%2Fts.ad.png

I've tried removing it using Header unset Cache-control, but no luck

Has anyone run into this before?

apache-2.4

3 Answers

  1. I'm guessing you've run into a bug because you have two different capitalizations of Cache-Control:

    Cache-Control: max-age=259200, no-cache="set-cookie"
Cache-control: no-cache="set-cookie"

    HTTP headers are case-insensitive, but you've probably run into an oddball edge case where Apache stops looking when it finds a match to what you're trying to remove - so the first one, Cache-Control, gets removed, while Cache-Control doesn't.

    Either find where in your config or code the Cache-control header is being set and have it fully capitalize to the normal Cache-Control (then a Header unset Cache-Control should nuke both values), or make Apache search for the matching case-insensitive name twice, which should hopefully work:

    Header unset Cache-Control
Header unset Cache-control
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  2. I failed to mention that my server(s) are behind a load balancer on AWS
    AWS ELB (what they call their load balancers) have a setting call stickiness
    When you turn it on, they set a cookie to make sure visitors consistently get sent to the same server

    This has the added side effect of adding the following header after your server fulfills the request:
    Cache-control: no-cache="set-cookie"

    I needed to turn off stickiness to prevent this header from being set

    In retrospect, I should've outlined my setup more to help debug this
    Thanks for your help Shane

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  3. Are you using mod_session?

    There's a bug about this:

    https://bz.apache.org/bugzilla/show_bug.cgi?id=61161

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