rack app + middleware example

example_rack.rb

require 'rubygems'
require 'rack'
require 'mongrel'
 
app = lambda do |env|
  [200, {}, "#{env['middleware.message']} world"]
end
 
class Middleware
  attr_reader :app
  def initialize(app)
    @app = app
  end
  
  def call(env)
    env['middleware.message'] = 'hi'
    app.call(env)
  end
end
 
app = Middleware.new(app)
 
handler = Rack::Handler.get('mongrel')
handler.run(app, :Host => 'localhost', :Port => 8080) do |server|
  trap(:INT) do
    server.respond_to?(:stop!) ? server.stop! : server.stop
  end
end