# frozen_string_literal: true require_relative 'utils' module Rack # Sets an "x-runtime" response header, indicating the response # time of the request, in seconds # # You can put it right before the application to see the processing # time, or before all the other middlewares to include time for them, # too. class Runtime FORMAT_STRING = "%0.6f" # :nodoc: HEADER_NAME = "x-runtime" # :nodoc: def initialize(app, name = nil) @app = app @header_name = HEADER_NAME @header_name += "-#{name.to_s.downcase}" if name end def call(env) start_time = Utils.clock_time _, headers, _ = response = @app.call(env) request_time = Utils.clock_time - start_time unless headers.key?(@header_name) headers[@header_name] = FORMAT_STRING % request_time end response end end end