Separate routes if subdomain is present in rails

Is there a way to separate routes in rails 3.1 when a subdomain is present? I want to use one collecti开发者_C百科on of routes when subdomains is used and one if not.

e.g

if request.subdomain.present?
  root ....
  resources ...
else
  root ....
  resources ...
end

Is something like this possible?

---

class SubdomainRoute

  def self.matches?(request)
    request.subdomain.present? && request.subdomain != "www"
  end

end

---

class NoSubdomainRoute

  def self.matches?(request)
    !request.subdomain.present?
  end

end

---

  constraints(NoSubdomainRoute) do
    resources :profile # matches if there is not a subdomain
  end

  constraints(SubdomainRoute) do
    resources :profile # matches if there is a subdomain
  end