Rails Best Practices

• Models
• Controllers
• Services
• Decorators
• Services
• Tests

SYNTAX

• string size should be:

100 or less characters - GOOD

100 - 120 characters - NOT BAD

120 characters - bad

• if you need divide code to several string leave dot or comma at the end of the string

BAD

User.select(:first_name, :last_name)
  .where(active: false)

User.notify!(from: '[email protected]'
  , message: 'DO IT!')

GOOD

User.select(:first_name, :last_name).
  where(active: false)

User.notify!(from: '[email protected]',
  message: 'DO IT!')

MODELS

define single model's structure for whole team and add it when you create new model. Each member of team have to wright code according to this structure, for example

class User < SuperClass
  # includes of foreign packages and modules

  # default_scope - BUT I don't think it is good idea to use it

  # attr_accessor, attr_reader

  # CALLBACKS

  # CONSTANTS

  # ENUMs

  # includes methods, like has_secure_password, uploaders etc

  # VALIDATORS

  # ASSOCIATIONS

  ## belongs_to
  ## has_one
  ## has_many
  ## has_and_belongs_to_many

  # SCOPES

  # CLASS METHODSDS

  # INSTANCE METHODS
end

---

enum - should be used in key-value format, not only as keys (like array)

BAD

enum status: [:active, :inactive, :draft]

GOOD

enum status: { active:  0, inactive: 1, draft: 2 }

---

use scopes only for getting ActiveRecord::Relation, not for single record

# bad

scope :last_active_user, -> { where(active: true).last }

# good

scope :active, -> { where(active: true) }

def self.last_active_user
  active.last
end

CONTROLLERS

some browsers have issue with caching pages, so you can face to next issue:

1. you use AJAX request for rendering page
2. go to another internet resource (for example from your site you go to http://google.com/)
3. click back button
4. instead expected your page, browser can render raw JavaScript

to avoid this situation in ApplicationController.rb add:

  before_action :headers_settings

  private

  def headers_settings
    if request.xhr?
      response.headers['Cache-Control'] = 'no-cache, no-store, max-age=0, must-revalidate'
      response.headers['Pragma'] = 'no-cache'
      response.headers['Expires'] = 'Fri, 01 Jan 1990 00:00:00 GMT'
    end
  end

SERVICES

Use comments before method definition. Comment can be consists of description and usage example.

Attributes should be wrap in asterisks *tax*

#
# make payment
# *tax* should be in cents ($1 is tax = 100)
# My::PaymentService.new(user).pay_tax(1_500)
def pay_tax(tax)
  .....
end

TESTS

Better Specs

---

use FactoryGirl for build instances

---

if you use stable value when you define attributes in FactoryGirl don't use {}

# bad

FactoryGirl.define do
  factory :article do
    published { true }
  end
end

# good

FactoryGirl.define do
  factory :article do
    published true
  end
end

---

use Faker for generate rundom attributes

---

use DatabaseCleaner for clean database around tests

---

write test in single string (isolate test)

# bad

it 'some description' do
  expect(...).to .....
end

# good

it { expect(...).to ... }

test should be clear and understandable without description

---

don't use instance variables, instead use let or let!

---

if you test function with time use TimeCop for stubing time

# bad
before do
  @user = User.create(first_name: 'John', age: 30)
end

# good
let(:user) { FactoryGirl.create(:user) }

---

when you write tests use same order as methods defined

---

skip callbacks in rails_helper.rb

RSpec.configure do |config|
  config.before(:suite) do
    User.skip_callback(:create, :before, :build_profile)
  end
end

if you need this callback in test just set it in before block and skip it in after block

---

don't save object to database if it hasn't any relations through database

# bad

let(:user) { create(:user) }

it { expect(user.full_name).to eq(user.first_name + ' ' + user.last_name) }

# good

let(:user) { build(:user) }

it { expect(user.full_name).to eq(user.first_name + ' ' + user.last_name) }

if you can, use double

let(:service) { double('service') }

allow(MyService).to receive(:new) { service }

---