Router

Namespaces allow parameter definitions and apply to every method within the namespace.
Its method has a number of aliases, including: group resource resources and segment. Use whichever reads the best for your API.

Ruby

namespace :statuses do
  namespace ":user_id" do
    desc "Retrieve a user's status."
    params do
      requires :status_id, type: Integer
    end
    get ":status_id" do
      params[:user_id]   |> IO.inspect
      params[:status_id] |> IO.inspect
    end
  end
end

You can conveniently define a route parameter as a namespace using route_param.

Ruby

namespace :statuses do
  route_param :id, type: String do
    desc "Returns all replies for a status."
    get :replies do
      params[:id] |> IO.inspect
    end

    desc "Returns a status."
    get do
      params[:id] |> IO.inspect
    end
  end
end