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
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?
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?
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
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
66. SINGLE RESPONSIBILITY PRINCIPLE
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