build_host_url

# File actionpack/lib/action_dispatch/http/url.rb, line 203
          def build_host_url(host, port, protocol, options, path)
            if match = host.match(HOST_REGEXP)
              protocol_from_host = match[1] if protocol.nil?
              host               = match[2]
              port               = match[3] unless options.key? :port
            end

            protocol = protocol_from_host || normalize_protocol(protocol).dup
            host     = normalize_host(host, options)
            port     = normalize_port(port, protocol)

            result = protocol

            if options[:user] && options[:password]
              result << "#{Rack::Utils.escape(options[:user])}:#{Rack::Utils.escape(options[:password])}@"
            end

            result << host

            result << ":" << port.to_s if port

            result.concat path
          end