[Zope-dev] [Summary] Caching prob with AHCM and headers

[Bjorn Stabell]

Just for the record to help others in the same situation...

PROBLEM
Apache (1.3.28 and 2.0.47) will not cache content with just an Expires
header, but it will correctly cache content with a Last-Modified header.
This problem has been reported before in 1999 by James Cooper, but the
bug request seems to have been forgotten/ left behind.

It makes sense for dynamic content to produce Expires headers, not
Last-Modified headers, so this is a problem.

Looking at the code for Zope, it seems that the standard HTTP
accelerator product used to produce a Last-Modified header, but no
longer does so, thus making it useless with the current versions of
Apache.

The problem has been re-reported to the Apache group with patches:
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=23129 (for Apache
1.3.28)
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=23130 (for Apache
2.0.47)


WORK-AROUNDS
1) Produce a Last-Modified header yourself by using
2) Patch Zope's standard HTTP accelerator product so that it produces a
Last-Modified header (the line is commented out now)

SOLUTIONS
3) Patch Apache (see bug report links above for patches)
4) Wait until the problem is hopefully fixed in Apache


Bye,
-- 
Bjorn Stabell bjorn at exoweb.net
Tel +86 (10) 65918490