Products.PolicyHTTPCacheManager 1.2

Delegates the setting of cache-related HTTP headers to CMF’s Caching Policy Manager.

Will remove a previously set Last-Modified header set by code inside Zope if you ask it to.

Because we can! wink

It’s simpler to make arbitrary content to play with the Caching Policy Manager this way. You just associate content that plays with the Zope’s ‘Cacheable’ interface to this Caching Manager and it will automatically set the HTTP headers at the right time.

Some code inside Zope (namely, FS{Image|File} and OFS.Image) will unconditionally set a ‘Last-Modified’ header. According to Geoff Davis this might be harmful when Internet Explorer is used so ‘Caching Policy Manager’ grew a setting to control the explicit setting of this header. However there was no way to explicitly remove a previously set header.