Per-Action Authentication/Authorization in Phoenix

I'm trying to find a workable pattern for authentication in Phoenix for an app that's very permissive about what you can view without an account.

I really miss my before_action callbacks from Rails, and I'm trying to find an effective replacement. But I seem to run into one problem after another, two of which I laid out in the following gist.

Example Code Here

Complete Application Here

Are there any standard solutions to this? Perhaps moving to something other than Guardian?