Question

We have an application that allows users to add/edit/replace/delete content (text, images, swfs, mp3s, etc). We want the admins to always have the latest updated files by using a no-cache header and when a user runs the application, everything gets/uses the cache.

I have looked into solutions and have tried using html meta tags like:

<meta http-equiv="expires" content="0" />
<meta http-equiv="cache-control" content="no-cache, no-store" />
<meta http-equiv="pragma" content="no-cache" />

But that doesn’t seem to be a good solution as this happens after the headers are created and doesn’t change the media (images, swfs, mp3s, etc) headers.

I wanted to use apache to set the headers and came across this code for this site:

<filesMatch "\.(html|htm|js|css)$">
FileETag None
<ifModule mod_headers.c>
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Wed, 11 Jan 1984 05:00:00 GMT"
</ifModule>
</filesMatch>

This seems to be a great solution, however the only real difference between when we need it cached and when it shouldn’t be cached is the URL (preview.jsp vs run.jsp), so we can’t match it by file type as most files are the same.

Does anyone have a good solution for this type of scenario?

Thanks.

EDIT:

Preview.jsp and run.jsp basically are the same only with different jsp and js processing. They read in the same content and media through an iframe. For example, they each look like:

<%
//Some JSP
%>
/* HTML Headers, JS, ETC */
<iframe id="contentFrame" seamless="1" src="http://somedomain.com/template.html"></iframe>
/* End HTML */

preview.jsp and run.jsp appear in the same directory and use all the same resources. I am looking for a solution to have preview.jsp not to cache anything and run.jsp to cache things.

Server is setup with Apache Tomcat.

Answer 1

A combination of SetEnvIf and Header might do the trick:

# Image, CSS and JavaScript requests normally contain the Referer header
# which tells apache which page is requesting the resource
# Use SetEnvIf directive to set a flag for internal uses

SetEnvIf Referer preview\.jsp force_no_cache

# Header directive optionally accepts env= argument
# If present, the directive is fired if the flag is set

Header unset ETag env=force_no_cache

# repeat for other headers