3.8 Routing Concerns
One of the fundamental principles Rails developers follow is Don’t Repeat Yourself (DRY). Even though thisis the case, the config/routes.rb file can be prone to having repetition in the form of nested routes that areshared across multiple resources.
resources :auctions do
resources :bids
resources :comments
resources :image_attachments, only: :index
end
resources :bids do
resources :comments
end
To eliminate some code duplication and to encapsulate shared behavior across routes, Rails 4 introduces the
routing method concern.
concern :commentable do
resources :comments
end
concern :image_attachable do
resources :image_attachments, only: :index
end
To add a routing concern to a RESTful route, pass the concern to the :concerns option.
# The :concerns option can accept one or more routing concerns.
resources :auctions, concerns: [:commentable, :image_attachable] do
resources :bids
end
resources :bids, concerns::commentable
