helpers.rb

#memo: devise/lib/devise/controllers/helpers.rb
      # The default url to be used after signing in. This is used by all Devise
      # controllers and you can overwrite it in your ApplicationController to
      # provide a custom hook for a custom resource.
      #
      # By default, it first tries to find a resource_root_path, otherwise it
      # uses the root path. For a user scope, you can define the default url in
      # the following way:
      #
      #   map.user_root '/users', :controller => 'users' # creates user_root_path
      #
      #   map.namespace :user do |user|
      #     user.root :controller => 'users' # creates user_root_path
      #   end
      #
      #
      # If the resource root path is not defined, root_path is used. However,
      # if this default is not enough, you can customize it, for example:
      #
      #   def after_sign_in_path_for(resource)
      #     if resource.is_a?(User) && resource.can_publish?
      #       publisher_url
      #     else
      #       super
      #     end
      #   end
      #
      def after_sign_in_path_for(resource_or_scope)
        scope = Devise::Mapping.find_scope!(resource_or_scope)
        home_path = :"#{scope}_root_path"
        respond_to?(home_path, true) ? send(home_path) : root_path
      end