normalize_path

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 92
          def normalize_path(path)
            raise ArgumentError, "path is required" if path.blank?
            path = Mapper.normalize_path(path)

            if path.match(':controller')
              raise ArgumentError, ":controller segment is not allowed within a namespace block" if @scope[:module]

              # Add a default constraint for :controller path segments that matches namespaced
              # controllers with default routes like :controller/:action/:id(.:format), e.g:
              # GET /admin/products/show/1
              # => { :controller => 'admin/products', :action => 'show', :id => '1' }
              @options.reverse_merge!(:controller => /.+?/)
            end

            if @options[:format] == false
              @options.delete(:format)
              path
            elsif path.include?(":format") || path.match(/\*[^\/]+$/)
              path
            else
              "#{path}(.:format)"
            end
          end