dragonfly should cache assets

[wenzowski]

fix for #1736

[parndt]

Thanks for this.

I'm unsure - it adds the weight of Rack::Cache to the core when it doesn't really need it.. Can rack-cache be enabled only when it is requested by Images or Resources?

[wenzowski]

Yes, it could be done.

I was hoping for a way to get Rails to inject it, but no ideas on that yet.

[ugisozols]

Small note: Rack::Cache will be disabled by default in Rails 4 (see rails/rails#7838) - if that makes any difference.

[ugisozols]

This PR makes Refinery::Core.verbose_rack_cache config redundant.

[wenzowski]

@ugisozols yes, I noticed rails/rails#7838. The big impact that will have on this is it allows setting config.action_dispatch.rack_cache = true instead of fussing with values for the hash.

So far I've only played with Refinery on Heroku. Rack::Cache is absolutely necessary on cedar (now default stack) since Cache-Control headers don't appear to have any effect as they're no longer using varnish (correct me if I'm wrong). I can see how running Refinery behind nginx (or any fast RCP) without Rack::Cache would likely be preferable performance-wise.

[wenzowski]

@parndt Ideally Dragonfly would be injected behind Rack::Cache if present else before whatever it needs to be in front of (don't know offhand).

When I first wrote this up, I recall not being able to depend on config.action_dispatch.rack_cache as an indicator of Rack::Cache injection status. It seems perfectly reliable in 3.1.3+ so that's probably the way to go.

I'll rewrite, time permitting.

[wenzowski]

@parndt Durr. By config.action_dispatch.rack_cache I meant config.action_controller.perform_caching