add host condition to rails route

gistfile1.rb

ActionController::Routing::Routes.draw do |map|
  map.connect "/", :controller => "admin",
    :conditions => { :subdomain => "admin" }
  map.connect "/", :controller => "blog"
  # ...
end

# jamisbuck/routing/routeset.rb
module JamisBuck
module Routing

  module RouteSetExtensions
    def self.included(base)
      base.alias_method_chain :extract_request_environment, :host
    end

    def extract_request_environment_with_host(request)
      env = extract_request_environment_without_host(request)
      env.merge :host => request.host,
        :domain => request.domain, :subdomain => request.subdomains.first
    end
  end

end
end

# jamis_buck/routing/route.rb
module JamisBuck
module Routing

  module RouteExtensions
    def self.included(base)
      base.alias_method_chain :recognition_conditions, :host
    end

    def recognition_conditions_with_host
      result = recognition_conditions_without_host
      result << "conditions[:host] === env[:host]" if conditions[:host]
      result << "conditions[:domain] === env[:domain]" if conditions[:domain]
      result << "conditions[:subdomain] === env[:subdomain]" if conditions[:subdomain]
      result
    end
  end

end
end

def recognize(path, env={})
  if (match = /\A\/?\Z/.match(path)) && conditions[:subdomain] === env[:subdomain]
    params = parameter_shell.dup
    params
  end
end

# init.rb
require 'jamis_buck/routing/routeset'
require 'jamis_buck/routing/route'
require 'action_controller/routing'

ActionController::Routing::RouteSet.send :include,
  JamisBuck::Routing::RouteSetExtensions

ActionController::Routing::Route.send :include,
  JamisBuck::Routing::RouteExtensions