rack-handler-default.rb

    def self.default(options = {})
      # Guess.
      if ENV.include?("PHP_FCGI_CHILDREN")
        # We already speak FastCGI
        options.delete :File
        options.delete :Port

        Rack::Handler::FastCGI
      elsif ENV.include?("REQUEST_METHOD")
        Rack::Handler::CGI
      else
        begin
          Rack::Handler::Mongrel
        rescue LoadError => e
          Rack::Handler::WEBrick
        end
      end
    end