Checking size of each request

app.rb

#in top of your app.rb file
require 'sinatra'
require 'response_size'
use Rack::ResponseSize

response_size.rb

module Rack
  # Save size of response
  class ResponseSize
    def initialize(app)
      @app = app
    end

    def call(env)
        response = @app.call(env)
        File.open("size.log", "a") do |f|
          # super ghetto
          f.write "Response Size: #{Marshal.dump(response).length}"
        end
      end
    end
  end
end