sandro · July 9, 2009 21:50
diff --git a/README b/README
 Spawn a long-running process in response to a POST request. The
 request spawns a child and immediately redirects, making the request
 non-blocking. The child changes the text on the index page from 
 "Running" to "Not running" after finishing its work.

 Instructions:
 ruby app.rb
 visit http://localhost:4567
 push "Run"
 notice the text says "Running"
 Refresh until the text says "Not running"
diff --git a/app.rb b/app.rb
 require 'rubygems'
 require 'sinatra'
 require 'haml'

 module State
  FILE_NAME = 'running'

  def self.running?
    File.exists? FILE_NAME
  end

  def self.reset!
    File.unlink FILE_NAME
  end

  def self.run!
    system 'touch', FILE_NAME
  end
 end

 get '/' do
  @running = State.running?
  haml :index
 end

 get '/reset' do
  State.reset!
  redirect '/'
 end

 post '/' do
  State.run!
  pid = fork { sleep 2; State.reset! }
  Process.detach pid
  redirect '/'
 end
diff --git a/index.haml b/index.haml
 - if @running
  Running
 - else
  Not running

 %form{:action => "", :method => "post"}
  %button{:type => "submit"} Run
	Spawn a long-running process in response to a POST request. The
	request spawns a child and immediately redirects, making the request
	non-blocking. The child changes the text on the index page from
	"Running" to "Not running" after finishing its work.

	Instructions:
	ruby app.rb
	visit http://localhost:4567
	push "Run"
	notice the text says "Running"
	Refresh until the text says "Not running"