This action adds the Last-Modified, Expires and
Cache-Control HTTP headers to the response.
This action will add the Last-Modified header to the response
with the time in which the request was executed, and an Expires
header at a specified time difference. Additionally, it will provide an
extra Cache-Control indicating the maximum age of the request
as a delta between the expiration and last modification dates.
This is useful (for example) when Cocoon is proxyied by a Web Server such
as Apache HTTPD running mod_cache, to indicate for each request how long
the output should be cached for.
To configure the difference between Last-Modified and
Expires this Action can be configured specifying
days, hours, minutes, and seconds in this way:
<map:action>s
<map:action name="xyz" src="org.apache.cocoon.acting.HttpCacheAction>"
<days>1</day>s
<hours>2</hour>s
<minutes>3</minute>s
<seconds>4</second>s
</map:actio>n
</map:action>s
Using this example configuration, the Expires header will
specify a date one day, two hours, three minutes and four seconds after
the time of the request (which will be in Last-Modified).
Note that if any of the parameters mentioned above is zero or
less than zero this action will modify the behaviour of the
resulting Cache-Control header to emit the keyword
no-cache.
This action will also return the three headers it added as sitemap
parameters called last-modified, expires and
cache-control (all lowercase).
author:
Pier Fumagalli
version:
CVS $Id: HttpCacheAction.java 30941 2004-07-29 19:56:58Z vgritsenko $ | 