200 OK instead of 304 Not Modified

Hi folks!

I've got a Plone 5.2.9 site running just fine but there's a bit of a hangnail that's bothering me.

All my CSS, JS, and images come back as "304 Not Modified" which is great, except for these three:

  • collective.js.jqueryui.custom.min.css?version=None
  • collective.js.jqueryui.custom.min.js?version=None
  • @@site-logo/better_diagram.png

These three and these three alone are always retrieved from the server with "200 OK". How do I convince Plone to treat these as "304 Not Modified" as well?

Registry settings, caching settings, and resource registry settings haven't yet yielded a clue—but then again, I'm a Plone noob! :stuck_out_tongue_closed_eyes:

At a high level, you have to figure out what kind of object it is (maybe you can traverse to its path at a Python prompt to check), and then make sure there is ZCML associating a plone.app.caching ruleset with that class or interface.