Special case robots.txt as Rails Metal

robots.rb

# Allow the metal piece to run in isolation
require(File.dirname(__FILE__) + "/../../config/environment") unless defined?(Rails)

class Robots
  def self.call(env)
    if env["PATH_INFO"] =~ /^\/robots.txt/
      return  disallow_multimedia if env["HTTP_HOST"] == 'www.something.biz' || env["HTTP_HOST"] =='something.biz'
      return  disallow_everything if env["HTTP_HOST"] =~ /\w*\.something.biz/
      return  disallow_everything if env["HTTP_HOST"] =~ /\w*\.somethingelse.com/
      allow_everything
    else
      [404, {"Content-Type" => "text/html"}, ["Not Found"]]
    end
  end
  
  def self.disallow_everything
    [200, {"Content-Type" => "text/plain"}, ["User-Agent: *\nDisallow: /"]]
  end
  
  def self.disallow_multimedia
    [200, {"Content-Type" => "text/plain"}, ["User-Agent: *\nDisallow: /multimedia"]]
  end
  
  def self.allow_everything
    [200, {"Content-Type" => "text/plain"}, ["User-Agent: *\nAllow: /"]]
  end
  
end