Can I get Apache 2.2 to set a particular response header if some other response header is missing

Question

I have an Apache 2.2 server running mod_proxy. We had a scenario where a response came through from the origin corrupted, it didn't have any content-type or cache-control headers. This meant that downstream proxies and clients cached the dodgy response.

What I would like to do is if the response doesn't have a content-type and cache-control header to insert a Cache-Control:max-age=0, no-cache header

Marcel · Answer 1 · 2013-04-05T17:07:26.303

2

from the rewritecond manual, I haven't tested but it seems that you could do something like:

RewriteCond %{HTTP:Cache-Control} ^$ [AND]
RewriteCond %{HTTP:Content-Type} ^$
Header add Cache-Control:max-age=0, no-cache

edited Apr 05 '13 at 17:07

answered Apr 04 '13 at 21:41

Marcel

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Unfortunately, that'll work only against request headers, not response headers. – Shane Madden Apr 05 '13 at 06:04
So with mod_header you'll be able to use just `Header add` – Marcel Apr 05 '13 at 17:07

score 2 · Accepted Answer · answered Apr 05 '13 at 06:10

I think to do this in Apache, you'd need to be running 2.4. mod_headers is the normal means of manipulating response headers, and it's not flexible enough to do what you want.

In 2.4, something like this should work:

<If "-z resp('Cache-Control') && -z resp('Content-Type')">
    Header set Cache-Control "max-age=0, no-cache"
</If>

Can I get Apache 2.2 to set a particular response header if some other response header is missing

2 Answers2