Based on InheritedResources # controller#resource Always returns the current resource instance which depends on the controller and the current action: posts#index => Post.new (?) posts#show => post posts#new => Post.new (?) posts#create => Post.new (?) posts#edit => post posts#update => post posts#destroy => post # controller#resources Returns an array containing the current resource and all of its inherited resources as defined by the controller through InheritedResources. E.g. on admin/sites/1/blogs/1/posts/1 the resources array equals [:admin, site, blog, post] # resource url helpers Defined for each get-able action, basically delegates to polymorphic_path with the current resources array: index_url, alias: collection_url new_url edit_url show_url, aliased resource_url # resource link helpers link_to_index, alias: link_to_collection link_to_new link_to_edit link_to_show