Construyendo Nuestro Propio Rack::Builder

Véase:

1. https://github.com/crguezl/rack-mybuilder

[~/local/src/ruby/sinatra/rack/rack-builder/own(master)]$ cat mybuilder.rb 
module Rack
  class MyBuilder

    def initialize(&block)
      @use = []
      instance_eval(&block) if block_given?
    end

    def use(middleware, *args, &block)
      @use << proc { |app| middleware.new(app, *args, &block) }
    end

    def run(app)
      @run = app
    end

    def to_app
      @use.reverse.inject(@run) { |app, middleware| middleware[app] }
    end

    def call(env)
      to_app.call(env)
    end

  end
end

[~/local/src/ruby/sinatra/rack/rack-builder/own(master)]$ cat decorator.rb 
class Decorator

  def initialize(app, *options, &block)
    @app = app
    @options = (options[0] || {})
  end

  def call(env)
    status, headers, body = @app.call(env)

    new_body = ""
    new_body << (@options[:header] || "----Header----<br/>")
    body.each {|str| new_body << str}
    new_body << (@options[:footer] || "<br/>----Footer----")

    [status, headers, [new_body]]
  end
end

[~/local/src/ruby/sinatra/rack/rack-builder/own(master)]$ cat app.rb 
require 'rack'
require 'thin'

require 'mybuilder'
require 'decorator'

app = Rack::MyBuilder.new do
  use Decorator, :header => "<strong>*********** header **********</strong><br/>"

  cheer = ARGV.shift || "<h1>Hello world!</h1>"
  run lambda { |env| [200, { 'Content-Type' => 'text/html' }, [ "<h1>#{cheer}</h1>" ]]}
end

Rack::Handler::Thin.run app, :Port => 3333, :Host => 'localhost'

[~/local/src/ruby/sinatra/rack/rack-builder/own(master)]$ cat Rakefile 
desc "run app server"
task :default => :server

desc "run app server"
task :server, :greet  do |t, args|
  cheer = args[:greet] || 'bye, bye!'
  sh "ruby -I. app.rb #{cheer}"
end

[~/local/src/ruby/sinatra/rack/rack-builder/own(master)]$ rake -T
rake default        # run app server
rake server[greet]  # run app server

[~/local/src/ruby/sinatra/rack/rack-builder/own(master)]$ rake server[tachaaaAAAAAANNN]
ruby -I. app.rb tachaaaAAAAAANNN
>> Thin web server (v1.5.1 codename Straight Razor)
>> Maximum connections set to 1024
>> Listening on localhost:3333, CTRL+C to stop