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DigitalOcean Ubuntu 14.04 x64 + Rails 4 + Nginx + Unicorn + PostgreSQL + Capistrano 3

Create a Droplet

SSH into Root

$ ssh [email protected]

Change Root Password

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Transactions

As your business logic gets complex you may need to implement transactions. The classic example is a bank funds transfer from account A to account B. If the withdrawal from account A fails then the deposit to account B should either never take place or be rolled back.

Basics

All the complexity is handled by ActiveRecord::Transactions. Any model class or instance has a method named .transaction. When called and passed a block, that block will be executed inside a database transaction. If there's an exception raised, the transaction will automatically be rolled back.

Example

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Замечали ли вы, что когда вы набираете что-то в google или yandex с ошибками, вас поправляют?

Возможно вы искали ... ?

Данная концепция называется триграммным поиском, она позволяет искать слова и фразы с опечатками.

Как это работает?

Каждое слово делится на сочетания из 3х букв – триграммы. На примере слова "Россия", будет:

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A small clone of Sinatra

For the purpose of learning.

Run the example app

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class Example < ActiveRecord::Base
 ## included modules & attr_*
 ## associations
 ## plugins
 ## named_scopes
 ## validations
 ## callbacks
 ## class methods
 ## public methods
 ## protected methods

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module CheckedAttributes
  def self.included(base)
    base.extend ClassMethods
  end
  module ClassMethods
    def attr_checked(attribute, &validation)
      define_method "#{attribute}=" do |value|
        raise 'Invalid attribute' unless validation.call(value)
        instance_variable_set("@#{attribute}" , value)
      end

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def screen_shot_and_save_page
  require 'capybara/util/save_and_open_page'
  path = "/#{Time.now.strftime('%Y-%m-%d-%H-%M-%S')}"
  Capybara.save_page body, "#{path}.html"
  page.driver.render Rails.root.join "#{Capybara.save_and_open_page_path}" "#{path}.png"
end

begin
  After do |scenario|
    screen_shot_and_save_page if scenario.failed?

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Price breakdown vs DigitalOcean, Vultr, Linode, OVH, and Online.net / Scaleway:

$5/mo

Provider	RAM	Cores	Storage	Transfer
LightSail	512MB	1	20GB SSD	1TB
DO	512MB	1	20GB SSD	1TB

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Automation Test

• End to End Test
• Integration Test
• Unit Test

In my mind, smoking test is end to end test, feature test is integration test. We want to enable everybody writing automation test.

End To End Test

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# lib/custom_logger.rb
class CustomLogger < Logger
  def format_message(severity, timestamp, progname, msg)
    "#{timestamp.to_formatted_s(:db)} #{severity} #{msg}\n"
  end
end

logfile = File.open("#{Rails.root}/log/custom.log", 'a')  # create log file
logfile.sync = true  # automatically flushes data to file
CUSTOM_LOGGER = CustomLogger.new(logfile)  # constant accessible anywhere