International

import subprocess
import time
import sys

if __name__ == "__main__":
    if len(sys.argv) != 2:
        exit("need an argument")
    to_run = sys.argv[1]
    proc = subprocess.Popen(to_run)
    print "start process with pid %s" % proc.pid

International

#include <iostream>

using namespace std;

int main(int argc,char* argv[]) {
  for(int i = 0;i < 5;i++) {
    cout << "Hello world!" << endl;
  }
  return 0;
}

International

public class SampleIteration {
  public static void main(String[] args) {
    for(int i = 0;i < 5;i++) {
      System.out.println("Hello world");
    }
  }
}

International

5.times { puts "Hello world" }

International

# Rails 3
"police".singularize
=> "polouse"

# Rails 4
"police".singularize
=> "police"

International

class PeopleController < ActionController::Base
  # This will raise an ActiveModel::ForbiddenAttributes exception because it's using mass assignment
  # without an explicit permit step.
  def create
    Person.create(params[:person])
  end

  # This will pass with flying colors as long as there's a person key in the parameters, otherwise
  # it'll raise a ActionController::MissingParameter exception, which will get caught by
  # ActionController::Base and turned into that 400 Bad Request reply.

International

class SomeBackgroundOperation
  def run
    # code to run in the background goes here
  end
end

# enqueing it to run
Rails.queue.push(SomeBackgroundOperation.new)

International

# config/environments/production.rb
# background thread
config.queue = ActiveSupport::Queue

# sidekiq ( rails4 branch )
config.queue = Sidekiq::Client::Queue

International

# make all mailers async
config.action_mailer.async = true

# make only a specific mailer async
class SomeMailer < ActionMailer::Base
  self.async = true
end

International

class MyController < ActionController::Base
  include ActionController::Live

  def stream
    response.headers['Content-Type'] = 'text/event-stream'
    100.times {
      response.stream.write "hello world\n"
      sleep 1
    }
    response.stream.close