This document outlines the agenda for a two-day Ruby on Rails advanced training course. Day 1 will cover Ruby basics like syntax, classes, modules and metaprogramming. It will also discuss Rails concepts like design patterns, ActiveSupport Concern, and Rails engines. Day 2 will involve discussing applications, gems, resolving problems, ActiveResource, security, caching and performance monitoring. The document also includes examples demonstrating Ruby concepts like objects, closures, exceptions and SOLID principles.

1. Ruby and Rails
Advanced Training
@gautamrege
@joshsoftware

2. Agenda - Day 1
Discuss Ruby basics
Syntax, classes, modules.
Meta-programming.
Closures
Rails concepts
Discussion around Rails design
patterns.
ActiveSupport Concern
Rails engines

3. Agenda - Day 2
Discuss your current Applications.
Gems currently in use
Resolving problems.
ActiveResource
Rails Security
Data Caching
Performace monitoring and improvement

4. Ruby is easy, right?

5. Ruby is easy, right?
1 + 1

6. Ruby is easy, right?
1 + 1
1.+(1)

7. Ruby is easy, right?
1 + 1
1.+(1)
1.+ 1

8. Ruby is easy, right?
1 + 1
1.+(1)
1.+ 1
1.send(:+, 1)

9. How many objects?

10. How many objects?
1 + 2 + 3

11. How many objects?
1 + 2 + 3

12. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)

13. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)

14. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)

15. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)

16. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)

17. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)

18. How many objects?
1 + 2 + 3
( 1.+(2) ).+(3)
FIVE
objects

19. Everything in Ruby
is an object
on which we call a method
to which we pass parameters
and an optional block of code

20. So, you know Ruby?

21. So, you know Ruby?
a[1] # What is the data type of a?

22. So, you know Ruby?
a[1] # What is the data type of a?
a = [‘a’, ‘b’] # Array

23. So, you know Ruby?
a[1] # What is the data type of a?
a = [‘a’, ‘b’] # Array
a = { 1 => ‘a’} # Hash

24. So, you know Ruby?
a[1] # What is the data type of a?
a = [‘a’, ‘b’] # Array
a = { 1 => ‘a’} # Hash
a = “abc” # String

25. So, you know Ruby?
a[1] # What is the data type of a?
a = [‘a’, ‘b’] # Array
a = { 1 => ‘a’} # Hash
a = “abc” # String
a = Proc.new { | x | p x } # proc

26. Multiplication

27. Multiplication
[1, 2, 3] * 2

28. Multiplication
[1, 2, 3] * 2
# => [1, 2, 3, 1, 2, 3]

29. Multiplication
[1, 2, 3] * 2
# => [1, 2, 3, 1, 2, 3]
[1, 2, 3] * “%”

30. Multiplication
[1, 2, 3] * 2
# => [1, 2, 3, 1, 2, 3]
[1, 2, 3] * “%”
# => “1%2%3”

31. There’s always an
easier way
Summation of [1, 2, 3, 4]

32. Non-ruby way!
sum = 0
!
for i in [1, 2, 3, 4]
sum += i
end
!
p sum

33. The Amateur!
sum = 0
!
[1, 2, 3, 4].each do |i|
sum += i
end
!
p sum

34. The Professional!
!
[1, 2, 3, 4].inject(0) do |sum, i|
sum + i
end

35. The Expert!
!
[1, 2, 3, 4].inject(:+)

36. Exceptions… never!
class Base
def method_missing(name, *args, &blk)
puts “Unknown method #{name}
called.”
end
end
b = Base.new
b.wtf

37. What’s in a name?
# User(id: integer, name: string)
class User < ActiveRecord::Base
end
u = User.name
u.name
u.name = “Gautam”

38. Accessing Data
class User
def initialize
@name = “someone”
end
end u = User.name
u.name
u.name = “Gautam”

39. Protected & Private
Private methods are inherited
Protected method can be called on
another object in same lineage
What the …

40. Module Mixins
class Shaktiman
include Spiderman
include Superman
end
irb> Shaktiman.ancestors
=> [ Shaktiman, Superman, Spiderman …]

41. Closures
sum = 0
[1, 2, 3, 4].each do |x|
sum += i
end
p sum
Anonymous functions?
Local variables scope?

42. Closures
!
Context sensitive block of code

43. Rails Design
Patterns

44. Rails Design
Patterns
Singleton

45. Rails Design
Patterns
Singleton
Factory

46. Rails Design
Patterns
Singleton
Factory
Observer

47. Rails Design
Patterns
Singleton
Factory
Observer
…

48. Rails Design
Patterns
Singleton
Factory
Observer
…
You cannot learn
Design Patterns!
!
You need to experience
them

49. SOLID Design
Patterns

50. SOLID principles
S - Single Responsibilty
O - Open / Closed
L - Liskov Substituion
I - Interface Segregation
D - Dependency Inversion

51. Single
Responsibility
Serves only one purpose.
Models - manage data
Controllers - manage logic
No logic in views!

52. Open / Closed
Open for Extension
Closed for modification

53. Open / Closed
Open for Extension
Closed for modification
ParseFeed

54. Open / Closed
Open for Extension
Closed for modification
ParseFeed
Atom RSS
ParseFeed

55. Liskov Substituion
Functionality should work for all
derived classes.
Let q(x) be a property provable about
objects x of type T. Then q(y) should
be true for objects y of type S where
S is subtype of T

56. Interface
Segregation
Classification based on behaviour
Vehicle
AirRoad
TrainCar RocketAirplane

57. Dependency
Inversion
High level modules should not
depend on low level modules
Modules should depend on
abstractions
Details should depend on
abstractions

58. ActiveSupport
Concern

59. Without ActiveSupport
Concerns
module Foo
def self.included(base)
base.class_eval do
scope :disable, -> { where(disabled: true) }
end
end
end
class Base
include Foo
end

60. With ActiveSupport
Concerns
module Foo
extend ActiveSupport::Concern
included do
scope :disable, -> { where(disabled: true) }
end
end
class Base
include Foo
end

61. Dependent Modules

62. Dependent Modules
module Foo
def self.included(base)
base.class_eval do
def self.foo_method
end
end
end
end

63. Dependent Modules
module Foo
def self.included(base)
base.class_eval do
def self.foo_method
end
end
end
end
module Bar
def self.included(base)
base.foo_method
end
end

64. Dependent Modules
module Foo
def self.included(base)
base.class_eval do
def self.foo_method
end
end
end
end
module Bar
def self.included(base)
base.foo_method
end
end
class Base
include Foo
include Bar
end

65. Dependent Modules
module Foo
def self.included(base)
base.class_eval do
def self.foo_method
end
end
end
end
module Bar
def self.included(base)
base.foo_method
end
end
class Base
include Foo
include Bar
end
add module
dependency
#!!

66. Module
dependencies

67. Module
dependencies
module Bar
include Foo
included do
def self.foo_method
end
end
class Base
include Bar
end

68. Module
dependencies
module Bar
include Foo
included do
def self.foo_method
end
end
class Base
include Bar
end
self = Bar
self != Base

69. Module
dependencies
module Bar
include Foo
included do
def self.foo_method
end
end
class Base
include Bar
end
self = Bar
self != Base

70. Module
dependencies
module Bar
extend ActiveSupport::Concern
include Foo
included do
def self.foo_method
end
end
class Base
include Bar
end
no including
extra modues
self = Base

71. Rails Engines

72. Engine power
Velocity App
CarRocket
Some custom
Functionality

73. CarRocket
Some custom
functionality

74. CarRocket
Some custom
functionality
Astronaut
Shuttles
M
M

75. CarRocket
Some custom
functionality
Astronaut
Shuttles
M
M
Driver
Rto
M
1

76. CarRocket
Some custom
functionality
Astronaut
Shuttles
M
M
Driver
Rto
M
1
Company

77. Quick Reference
rails plugin new <name> —mountable
rails g scaffold <model> <name>:<type>
test/dummy: testing engine.

78. GamePlay - Car
Create Car engine
Create RTO scaffold
name:string code:string
Create Driver scaffold
name:string rto_id:integer
has_licence:boolean

79. Testing - Car
rake db:migrate
cd test/dummy
rails s
http://localhost:300/car

80. GamePlay-Rocket
Create Rocket engine
Create Astronaut scaffold
name:string degree:text
Create Shuttle scaffold
name:string launch_from:text
Create Space_flights scaffold
shuttle_id:integer astronaut_id:integer
launch_on:date

81. Testing - Rocket
rake db:migrate
cd test/dummy
rails s
http://localhost:3000/rocket

82. Application Stuff
rails new velocity
update Gemfile
gem ‘car’, path: <path>
gem ‘rocket’, path: <path>
config/routes:
mount Car::Engine, at: ‘/car’
mount Rocket::Engine, at: ‘/engine’

83. Application Logic
Company scaffold
name:string make_cars:boolean
make_rockets:boolean
owner:string

84. Using Application
models in engines.
Add migration for owner_id
class Shuttle
belongs_to :owner, class: “Company”
end
NEVER hardcode associations directly
in engines. Use class option.

85. More ???

86. Devise
Authentication
Gemfile
gem ‘devise’
rails g devise:install
rails g device user
rake db:migrate

87. Inherit from App
# rocket/app/controller/rocket/application_controller.rb
class Rocket::ApplicationController <
ApplicationController
end
# shuttles_controller.rb
class ShuttleController < ApplicationControler
before_action :authenticate_user!
end

88. Checklist
Automatic namespace resolution.
Views that access models require to be fully
resolved.
rake <engine>:install:migrations
rake railties:install:migrations
Controllers permit parameters
No hardcoded associations from top-level app.

89. Discussions!
ActiveResource
Rails Security
Caching
Performance
Q & A

90. ActiveResource

91. Rails Security
Authenticity Token
Protect from forgery
CSRF
SQL injection
XSS - html_safe & raw
http://guides.rubyonrails.org/security.html

92. Rails Caching
Cache Store:
memory, file, memcached, ehcache, custom
Page & Action caching (DEPRECATED)
http://signalvnoise.com/posts/3113-how-key-based-
cache-expiration-works
Fragment caching
Query caching
http://guides.rubyonrails.org/caching_with_rails.html

93. Rails Performance
NewRelic Monitoring
Log file and debugging
Load Testing
Concurrency testing
Performance Benchmark using benchmark-ips
http://guides.rubyonrails.org/v3.2.13/
performance_testing.html