Introduction to Active Support

Presented for Metis students a thoughtbot office

Transcript

1. Introduction to
 Active Support
2. Notations $ irb # Shell command > str = "Hello World" # Ruby code #=> Hello World # Return value
3. Notations Object.method <= Class method Object#method <= Instance method
4. What is Active Support?
5. "Utility classes and Ruby extensions from Rails" (From https://github.com/rails/rails/tree/master/activesupport)
6. Utility Classes • ActiveSupport::Callbacks • ActiveSupport::HashWithIndifferentAccess • ActiveSupport::MessageEncrypter • ActiveSupport::MessageVerifier • ... etc ...
7. Ruby Extensions • object.present? / object.blank? • date.yesterday / date.tomorrow • 1.day.ago / 2.months.from_now • ... etc ...
8. Part of Rails framework Available to be used inside Rails
9. # To use outside Rails $ gem install activesupport # in Ruby > require "activesupport/all"
10. Digging Deeper
11. Callbacks
12. Callbacks • Helpers to define and run callbacks • Use in Active Record, Action Pack, etc. • before_action, after_action, before_save, etc.
13. Callback Example class User < ActiveRecord::Base before_save :do_something def do_something # ... end end
14. Callback Example class Account include ActiveSupport::Callbacks define_callbacks :save set_callback :save, :before, :do_something def save run_callbacks :save do # ... end end def do_something # ... end end
15. MessageEncrypter Encrypts message with a key
16. MessageEncrypter > salt = SecureRandom.random_bytes(64) > key = ActiveSupport::KeyGenerator. new('password').generate_key(salt) > crypt = ActiveSupport::MessageEncryptor.new(key) > encrypted_data = crypt. encrypt_and_sign('my secret data') > crypt.decrypt_and_verify(encrypted_data)
17. Notifications
18. Notifications • Uses for logging purposes • Executer instrument an event that should be subscribed to: • Action View's "render" • Active Record's "execute SQL" • etc. • Listeners subscribe to those events from another part of the application
19. TimeZone
20. TimeZone • Contains full mapping of time zones • Perform time zone conversions
21. TimeZone > ActiveSupport::TimeZone.all > ActiveSupport::TimeZone.us_zones > Time.zone = "America/New_York" > time = Time.zone.now #=> "Fri, 20 Jun 2014 14:35:00 EDT -04:00" > time.in_time_zone("America/Los_Angeles") #=> "Fri, 20 Jun 2014 11:35:00 PDT -07:00"
22. Core Extensions
23. Array
24. Array#from Array#to
25. Array#from Array#to > array = [1, 2, 3, 4] > array.from(2) #=> [3, 4] > array.to(2) #=> [1,2,3]
26. Array#second Array#third Array#fourth Array#fifth Array#forty_two
27. Array Access > array = (1..100).to_a > array.first #=> 1 > array.second #=> 2 > array.third #=> 3 > array.fourth #=> 4 > array.fifth #=> 5 > array.forty_two #=> 42
28. Array#to_sentence
29. Array#to_sentence > fruits = %w(banana strawberry kiwi) > fruits.to_sentence #=> "banana, strawberry, and kiwi > sports = %w(football baseball) > sports.to_sentence #=> "football and baseball"
30. Array#in_groups_of Array#in_groups
31. Array#in_group_of > array = (1..10).to_a > array.in_group_of(3) # => [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, nil, nil]]
32. Array#in_groups > array = (1..10).to_a > array.in_groups(3) #=> [[1, 2, 3, 4], [5, 6, 7, nil], [8, 9, 10, nil]]
33. Date, Time, DateTime
34. Date.current Date.yesterday Date.tomorrow
35. Time#beginning_of_day Time#middle_of_day Time#end_of_day
36. Time#beginning_of_hour Time#end_of_hour
37. Time#all_day Date#all_week Date#all_month Date#all_year
38. Time#today? Time#past? Time#future?
39. Hash
40. Hash#deep_merge
41. Hash#deep_merge > h1 = { a: true, b: { c: [1, 2, 3] } } > h2 = { a: false, b: { x: [3, 4, 5] } } > h1.deep_merge(h2) #=> { a: false, b: { c: [1, 2, 3], x: [3, 4, 5] } }
42. Hash#except
43. Hash#except > hash = { one: 1, two: 2 } > hash.except(:one) #=> { two: 2 }
44. Hash#with_indifferent_access
45. # In Controller > params[:id] #=> 1 > params['id'] #=> 1 > params.class #=> ActiveSupport::HashWithIndifferentAccess
46. Hash#with_indifferent_access > hash = { one: 1 }.with_indifferent_access > hash[:one] #=> 1 > hash['one'] #=> 1
47. Hash#stringify_keys Hash#symbolize_keys
48. Hash#stringify_keys Hash#symbolize_keys > hash = { one: 1, 'two' => 2 } > hash.stringify_keys #=> { 'one' => 1, 'two' => 2 } > hash.symbolize_keys #=> { one: 1, two: 2 }
49. Hash#reverse_merge
50. Hash#reverse_merge > h1 = { one: 'one' } > h2 = { one: 'uno', two: 'dos' } > h1.merge(h2) #=> { one: 'uno', two: 'dos' } > h1.reverse_merge(h2) #=> { one: 'one', two: 'dos' }
51. Hash#slice
52. Hash#slice > hash = { one: 1, two: 2, three: 3 } > hash.slice(:one, :two) #=> { one: 1, two: 2 }
53. Integer
54. Integer#ordinalize
55. Integer#ordinalize > 1.ordinalize #=> "1st" > 2.ordinalize #=> "2nd"
56. Integer#ordinal
57. Integer#ordinalize > 1.ordinal #=> "st" > 2.ordinalize #=> "nd"
58. Integer#days Integer#months Integers#years
59. Examples > 1.month.ago > 1.month.from_now > 1.month.since(time) > 1.year.from(time)
60. Object
61. Object#present? Object#blank?
62. Object#try
63. Object#try > user = nil > user.name #=> NoMethodError > user.try(:name) #=> nil
64. Object#presence
65. Object#presence > name = "John" > puts "Hello #{name}" #=> "Hello John"
66. Object#presence > name = "" > puts "Hello #{name}" #=> "Hello "
67. Object#presence > name = "" > puts "Hello #{name.present? ? name : "Guest"}" #=> "Hello Guest"
68. Object#presence > name = "" > puts "Hello #{name.presence || "Guest"}" #=> "Hello Guest"
69. String
70. String#to_time String#to_date String#to_datetime
71. String#to_time String#to_date String#to_datetime > "13-12-2012".to_time #=> 2012-12-13 00:00:00 -0500 > "1-1-2012".to_date #=> Sun, 01 Jan 2012 > "1-1-2012".to_datetime #=> Sun, 01 Jan 2012 00:00:00 +0000
72. String#truncate
73. String#truncate > "Hello World".truncate(8) #=> "Hello Wo..."
74. String#singularize String#pluralize String#camelize String#titleize String#humanize
75. Inflections Example > "man".pluralize #=> "men" > "octopi".singularize #=> "octopus" > "user_name".camelize #=> "UserName" > "hello world".titlize #=> "Hello World" > "full_name".humanize #=> "Full name"
76. String#inquiry
77. String#inquiry > color = "red".inquiry > color.red? #=> true > color.blue? #=> false > Rails.env.development?
78. http://guides.rubyonrails.org/active_support_core_extensions.html