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.

Methods
C
N
Constants
FORMAT_STRING = "%0.6f".freeze
 
HEADER_NAME = "X-Runtime".freeze
 
Class Public methods
new(app, name = nil)
# File lib/rack/runtime.rb, line 14
def initialize(app, name = nil)
  @app = app
  @header_name = HEADER_NAME
  @header_name += "-#{name}" if name
end
Instance Public methods
call(env)
# File lib/rack/runtime.rb, line 20
def call(env)
  start_time = Utils.clock_time
  status, headers, body = @app.call(env)
  request_time = Utils.clock_time - start_time

  unless headers.has_key?(@header_name)
    headers[@header_name] = FORMAT_STRING % request_time
  end

  [status, headers, body]
end