A lot of people ask me whether we use Rails controllers for our API. We don’t, we use Grape. Grape is a Rack-based system and a DSL that provides a cleaner separation, some API-specific functionality and generally a better syntax. Now that we have dealt with exceptions and authentication we realized that the amount of functionality exposed in the API has grown exponentially in one single Ruby file. Let’s refactor it into modules.
Here’s our current code from API v1.
class Api_v1 < Grape::API prefix 'api' version 'v1' rescue_from :all, :backtrace => true error_format :json helpers do def authenticated if warden.authenticated? return true else error!('401 Unauthorized', 401) end end end namespace :me do # GET /api/v1/me/info get "info" do authenticated current_user.as_json({properties: :self}) end end end We want a separate file for helpers and for the me API. We can move the helpers into a module and include it normally.
module ApiAuth def authenticated ... end end The namespace DSL is a bit tricky. Those namespace and get are actually namespace functions in Grape::API. Fortunately Ruby calls included(module) for every included module. We can call the public methods on a namespace function ourselves.
module Api_v1_Me def self.included(api) api.namespace :me do # GET /api/v1/me/info get "info" do ... end end end end Let’s combine all of this into an API class.
class Api_v1 < Grape::API prefix 'api' version 'v1' rescue_from :all, :backtrace => true error_format :json helpers do include ApiAuth end include Api_v1_Me end The nice thing about this implementation is that we can now compose an API v2 with a bunch of v1 modules and some v2 ones. The not-so-nice part is the included construct. I’d like to write the following.
module Api_v1_Me include Grape::APIModule namespace :me do # GET /api/v1/me/info get "info" do ... end end end Beer to anyone who can implement this, I tried for hours, in vain - I think Grape will need some major refactoring to support modules this way. Fork Grape on Github.