AllAbout 022 EventMachine

defer.rb

require 'bundler/setup'
Bundler.require

require 'open-uri'

EM.run do
  puts "main: #{Thread.current}"

  operation = -> do
    puts "defer operation: #{Thread.current}"
    open('http://allabout.co.jp/'){|f| f.read.scan(/<title>(.*)<\/title>/) }
  end

  callback  = -> (result) do
    puts "callback: #{Thread.current}"
    puts result
  end

  puts '--- calling defer'
  EM.defer(operation, callback)
  puts '--- called defer'

  EM.stop
end

deferrable.rb

require 'bundler/setup'
Bundler.require

class Dice
  include EM::Deferrable
  def throw
    rand(1..6)
  end
end

EM.run do
  dice = Dice.new

  # 成功時の処理を登録
  dice.callback do |n|
    puts "it's odd: #{n}"
  end

  # 失敗時の処理を登録
  dice.errback do |n|
    puts "it's even: #{n}"
  end

  case num = dice.throw
  when 1,3,5
    dice.succeed(num) # diceオブジェクトに成功状態をセット
  when 2,4,6
    dice.fail(num)    # diceオブジェクトに失敗状態をセット
  end

  EM.stop
end

Gemfile

source 'https://rubygems.org'

gem 'eventmachine'

run_defer.sh

$ ruby defer.rb
main: #<Thread:0x007fe2e18cb790>
--- calling defer
--- called defer
defer operation: #<Thread:0x007fe2e20d7970>
callback: #<Thread:0x007fe2e18cb790>
All About（オールアバウト）

run_deferrable.sh

$ ruby deferrable.rb
it's odd: 5

$ ruby deferrable.rb
it's even: 2

run_server.sh

$ ruby server.rb
running echo server on 8081


### 別コンソールから8081に接続, 話しかける
$ telnet 127.0.0.1 8081
hi
>>> echo: hi

server.rb

require 'bundler/setup'
Bundler.require

module EchoServer
  def post_init
    puts '-- connection established'
  end

  def receive_data(data)
    send_data ">>> echo: #{data}"
  end
end

EventMachine::run {
  EventMachine::start_server '127.0.0.1', 8081, EchoServer
  puts 'running echo server on 8081'
}