Swagger`无法自动加载常量`

Question

Swagger docs are failing to build, with the error:

LoadError: Unable to autoload constant ThingsController, expected /path/to/my/app/controllers/api/things_controller.rb to define it

The weird thing is, the class is defined there, and the app is working: only swagger fails.

things_controller.rb contains

class Api::ThingsController < ActionController::Base
  swagger_controller :things, "Things"

  swagger_api :index do
    summary "Returns list of things"
  end
end

Any ideas why Swagger would be unable to find a functioning class in the file where it is defined?

Answer 1

By convention in rails (and this is enforced by autoloader), file paths should match namespaces

Additionally, you probably have autoloader kicking in when trying to load a things_controller class (my guess is that it happens from within Act things_controller). It looks for a things_controller.rb file in load path, find it in app/controller/ and thus load that file so it can find the ThingsController class.

it should be in app/controller/things_controller.rb.

class ThingsController < ActionController::Base
  swagger_controller :things, "Things"

  swagger_api :index do
    summary "Returns list of things"
  end
end

Refer this link ( https://coderwall.com/p/bjk3pa/documenting-rails-based-rest-api-using-swagger-ui )

Answer 2

This had a very strange conclusion: there are two ThingsController s, one in the API namespace, Api::ThingsController and one in the base namespace ThingsController . The one in the base namespace was removed but was still referred to by the routes.rb , which was a bug in the codebase.

The error being reported was that it couldn't find Api::ThingsController in /path/to/my/app/controllers/api/things_controller.rb but instead it was failing to find ThingsController in /path/to/my/app/controllers/things_controller.rb .

My conclusion is that there is a bug in Rails error reporting in the lazy loader. It reports the wrong error. If you get a nonsensical message, check that there isn't a name clash .

I think this is unrelated to Swagger, but triggered by it because (I guess) it spiders the source tree looking for Swagger annotations.