Rack Example

config.ru

# Use:
# This is in file config.ru
# 1) gem install rack
# 2) rackup
# 3) visit http://localhost:9292 in browser
# 4) Timer info will be in console
# 5) when changing code, will have to restart rackup

# Include rack
require 'rack'

# Our App
class HelloApp
  def self.call(env)
    [200, {'Content-Type' => 'text/html'}, ["Hello there."]]
  end
end

# Timer middlewhere
class Timer
  def initialize(app)
    @app = app
  end

  def call(env)
    before = Time.now.to_f
    response = @app.call env
    puts "#{(Time.now.to_f - before) * 1000.0} milliseconds."
    response
  end
end

# Using Rack Builder to set up App and Middleware
app = Rack::Builder.new do
  use Timer
  run HelloApp
end

# Run the app
run app