Stop being Rails developer

Transcript

1. WHY LIFE WITH RUBY ON RAILS BECOMES SO HARD AFTER

   FEW MONTHS OF DEVELOPMENT? IVAN NEMYTCHENKO

2. IVAN NEMYTCHENKO > 14 years in IT > cofounded 2

   IT-companies > occasional speaker > coorganized 2 HappyDev conferences > worked in a startup > worked as project-manager > working with Rails since 2006 > author of RailsHurts.com > internship for ruby junior developers: SkillGrid > twitter: @inem

3. WHAT IS WRONG WITH RAILS?

4. SAME PATTERN

5. None
6. None
7. None
8. None

9. RAILSHURTS.COM/MESS

10. RAILS-WAY IS NOT ENOUGH

11. RAILS WORLD is so cool that we don't even have

    whole class of problems millions of java programmers struggring every day

12. THESE THINGS MIGHT HELP YOU > SOLID principles > Design

    Patterns > Refactoring techniques > Architecture types > Code smells identification > Best practices of testing

13. PRINCIPLES. MISUNDERSTOOD. APPLIED.

14. DRY «DON'T REPEAT YOURSELF» RAILSHURTS.COM/_DRY

15. JUST AVOID DUPLICATION, RIGHT?

16. None

17. EVERYTHING HAS ITS PRICE

18. PRICE: MORE RELATIONS

19. «Duplication is far cheaper that wrong abstraction» — Sandi Metz

20. KISS «KEEP IT SIMPLE, STUPID» RAILSHURTS.COM/_KISS

21. RAILS IS SIMPLE, RIGHT?

22. ACTIVERECORD class User < ActiveRecord::Base end

23. ACTIVERECORD

24. ACTIVERECORD > input data coercion > setting default values >

    input data validation > interaction with the database > handling nested structures > callbacks (before_save, etc...)

25. - WHY SHOULD I CARE?

26. Polymorphic STI model which belongs to another polymorphic model through

    third model, which also has some valuable JSON data stored in Postgres using hstore.

27. WHAT ARE YOU GONNA DO? > reorganize associations > become

    Rails core contributor

28. IT IS GOING TO BE PAINFUL

29. PAINFUL BECAUSE OF THE COMPLEXITY

30. RAILS IS NOT SIMPLE. IT IS CONVENIENT.

31. FAT MODEL, SKINNY CONTROLLER RAILSHURTS.COM/_SKINNY

32. RIGHT PROBLEM IDENTIFIED

33. BUT IT IS ONLY PART OF THE PROBLEM

34. YOU SHOULD HAVE NO FAT CLASSES AT ALL

35. *HINT: PROPER SOLUTION REQUIRES THINKING OUT OF MVC BOX

36. RAILS IS NOT YOUR APPLICATION RAILSHURTS.COM/_APP

37. It just doesn't make sense. Here's my Rails application. Here's

    app folder. What's wrong?
38. None
39. None

40. RAILSHURTS.COM/_CLEAN

41. HEXXAGONAL ARCHITECTURE RAILSHURTS.COM/_HEXX

42. YAGNI «YOU AREN'T GONNA NEED IT» RAILSHURTS.COM/_YAGNI

43. WHAT IF YOUR APP DOESN'T NEED PERSISTANCE YET?

44. WHAT IF YOUR APP CORE DOESN'T NEED WEB FRAMEWORK YET?

45. «Question everything generally thought to be obvious» — Dieter Rams

46. THREE RULES FOR DEVELOPERS WHO ARE NOT SURE OF ONE'S

    STRENGTH > Do not apply DRY principle too early > Remember about Single Responsibility Principle > Learn how to apply Design Patterns
47. None

48. LET'S GET OUR HANDS DIRTY!

49. FEATURE #1: USERS REGISTRATION

50. FEATURE #1: USERS REGISTRATION

51. SINGLE TABLE INHERITANCE !   CONDITIONAL VALIDATIONS !

52. BOTH STI AND CONDITIONAL VALIDATIONS ARE JUST WORKAROUNDS THE PROBLEM

    IS DEEPER!

53. SINGE RESPONSIBILITY PRINCIPLE: A CLASS SHOULD HAVE ONLY ONE REASON

    TO CHANGE

54. OUR MODEL KNOWS ABOUT HOW.. > admin form is validated

    > org_user form is validated > guest_user form is validated > user data is saved

55. FORM OBJECT !   

56. COOKING FORM OBJECT (STEP 1) class Person attr_accessor :first_name, :last_name

    def initialize(first_name, last_name) @first_name, @last_name = first_name, last_name end end

57. COOKING FORM OBJECT (STEP 2) class Person attr_accessor :first_name, :last_name

    def initialize(first_name, last_name) @first_name, @last_name = first_name, last_name end include ActiveModel::Validations validates_presence_of :first_name, :last_name end

58. COOKING FORM OBJECT (STEP 3) class Person include Virtus.model attribute

    :first_name, String attribute :last_name, String include ActiveModel::Validations validates_presence_of :first_name, :last_name end

59. FORM OBJECT class OrgUserInput include Virtus.model include ActiveModel::Validations attribute :login,

    String attribute :password, String attribute :password_confirmation, String attribute :organization_id, Integer validates_presence_of :login, :password, :password_confirmation validates_numericality_of :organization_id end

60. USING FORM OBJECT def create input = OrgUserInput.new(params) if input.valid?

    @user = User.create(input.to_hash) else #... end end

61. FOUR SIMPLE OBJECTS INSTEAD OF ONE COMPLEX

62. FEATURE #2: BONUSCODE REDEEM

63. def redeem unless bonuscode = Bonuscode.find_by_hash(params[:code]) render json: {error: 'Bonuscode

    not found'}, status: 404 and return end if bonuscode.used? render json: {error: 'Bonuscode is already used'}, status: 404 and return end unless recipient = User.find_by_id(params[:receptor_id]) render json: {error: 'Recipient not found'}, status: 404 and return end ActiveRecord::Base.transaction do amount = bonuscode.mark_as_used!(params[:receptor_id]) recipient.increase_balance!(amount) if recipient.save && bonuscode.save render json: {balance: recipient.balance}, status: 200 else render json: {error: 'Error during transaction'}, status: 500 end end end
64. None
65. None

66. SINGLE RESPONSIBILITY PRINCIPLE

67. None

68. bonuscode.redeem_by(user) OR user.redeem_bonus(code) ?

69. SERVICE OBJECT! (USE CASE, INTERACTOR)   

70. COOKING SERVICE OBJECT (STEP 1) class RedeemBonuscode def redeem unless

    bonuscode = Bonuscode.find_by_hash(params[:code]) render json: {error: 'Bonuscode not found'}, status: 404 and return end if bonuscode.used? render json: {error: 'Bonuscode is already used'}, status: 404 and return end unless recipient = User.find_by_id(params[:receptor_id]) render json: {error: 'Recipient not found'}, status: 404 and return end ActiveRecord::Base.transaction do amount = bonuscode.mark_as_used!(params[:receptor_id]) recipient.increase_balance!(amount) if recipient.save && bonuscode.save render json: {balance: recipient.balance}, status: 200 else render json: {error: 'Error during transaction'}, status: 500 end end end end

71. COOKING SERVICE OBJECT (STEP 2) class RedeemBonuscode def run!(params) unless

    bonuscode = Bonuscode.find_by_hash(params[:code]) raise BonuscodeNotFound.new end if bonuscode.used? raise BonuscodeIsAlreadyUsed.new end unless recipient = User.find_by_id(params[:receptor_id]) raise RecipientNotFound.new end ActiveRecord::Base.transaction do amount = bonuscode.mark_as_used!(params[:receptor_id]) recipient.increase_balance!(amount) recipient.save! && bonuscode.save! end recipient.balance end end         

72. COOKING SERVICE OBJECT (STEP 3) def redeem use_case = RedeemBonuscode.new

    begin recipient_balance = use_case.run!(params) rescue BonuscodeNotFound, BonuscodeIsAlreadyUsed, RecipientNotFound => ex render json: {error: ex.message}, status: 404 and return rescue TransactionError => ex render json: {error: ex.message}, status: 500 and return end render json: {balance: recipient_balance} end

73. BUSINESS LOGIC / CONTROLLER SEPARATION

74. 7 Patterns to Refactor Fat ActiveRecord Models railshurts.com/_7ways * *

    * Arkency railshurts.com/_arkency * * * Adam Hawkins railshurts.com/_hawkins