如何在Rails初始化程序中使用关注点？

Question

In my Ruby on Rails project I have a concern app/controllers/concerns/common.rb :

module Common
  extend ActiveSupport::Concern

  private

  def foo
  end

end

I want to use its foo function inside config/initializers/devise.rb :

Devise.setup do |config|
  ...
  foo
  ...
end

For now I failed to somehow load common.rb inside config/initializers/devise.rb - how to do it?

Currently I'm using a workaround - I define the foo function inside config/application.rb and it works, but it breaks the DRY principles.

Answer 1

Theoretically you could include your concern inside the devise config:

Devise.setup do |config|
  include Common
  foo
  # ...
end

That way how ever you're including the method on ruby's main object / top level context.

Alternatively you could extend 'config' (= Devise) with your module, and call the method foo on config.

Devise.setup do |config|
  config.send(:extend, Common)
  config.foo
  # ...
end

To make this work however you would need to make foo a public method, otherwise you won't be able to call it like that.

If you're overall goal is to avoid code duplication it is hard to tell you what the best solution would be, without knowing more about what you want to achieve, eg what shared code you want to extract from your devise config.