I noticed that the block version of an exposure pretty much runs without any usable context. The context it currently uses is the class of the entity, which doesn't really provide much, passing in the object being wrapped and the options.

I think it would be a lot cleaner and more intuitive if the block was evaluated in the context of the instance around here.

Here's an example use case where that cleans things up:

class ProductEntity < Grape::Entity expose :local_prices do prices.select(&:local?) end expose :web_prices do prices.select(&:web?) end private def prices @prices ||= expensive_api_call end end

This doesn't work currently because the prices method is on the instance but the block gets evaluated on the class. Wouldn't want to add the prices method to the class because it is stateful.

Alternatively (and I prefer this), you could have exposures see if the entity responds to it first, and if not delegate to the object as normal. I think Roar does this and it is much easier to build a proper facade that way. Admittedly, it is a more breaking API change. For comparison:

class ProductEntity < Grape::Entity expose :local_prices expose :web_prices expose :attribute_on_the_product private def web_prices prices.select(&:web?) end def local_prices prices.select(&:local?) end def prices @prices ||= expensive_api_call end end

Thoughts?