Domain Driven Design Kinda

Explains how we kinda do Domain Driven Design in our Ruby on Rails at Product Hunt.

1. Domain Driven Desig n kinda
2. 👋
12. Refactoring
13. Life Goals
15. Domain Driven Design
16. ...kinda 🙈
17. Product Hunt favored Domain Driven Desig n
21. “Domain-driven design (DDD) is the concept that the structure and language of software code (classes, methods, functions, variables).” What is Domain Driven Design?
22. What problems does DDD solve? “Developers are too wrapped up with technology and trying to solve problems using technology rather than careful thought and design” 1
23. What problems does DDD solve? “The database is given too much priority, and most discussions about the solutions center around the database and a data model rather than business processes and operations.” 2
24. What problems does DDD solve? “Developers don’t give proper emphasis to naming objects and operations according to the business purpose that they fi ll.” 3
25. What problems does DDD solve? “Application logic is disjointed and hard to follow. It is hard to see an overview of the application features” 4
26. What are the issues with traditional DDD? “In order to help maintain the model as a pure and helpful language construct, the team must typically implement a great deal of isolation and encapsulation within the domain model. Which overcomplicates the system.” 1
27. What are the issues with traditional DDD? “Rails and Node doesn't fi t very well with DDD mindset. DDD comes from Java and similar languages.” 2
28. What are the issues with traditional DDD? “A lot of DDD practices are focused on consultancy model and are used for model complicated business processes.” 3
29. Product Hunt favored Domain Driven Desig n
31. What is Domain Driven Design ?
32. Ubiquitous Language “A language structured around the domain model and used by all team members to connect all the activities of the team with the software.”
33. Ubiquitous Language “There are only two hard things in Computer Science: cache invalidation and naming things.” -- Phil Karlton
34. Ubiquitous Language app/models/use.rb 🙈
35. Ubiquitous Language app/models/use.rb 🤮
36. Ubiquitous Language app/models/stack_item.rb 👍
37. Ubiquitous Language app/model/founder_club/member.rb 👍
38. Domains “A sphere of knowledge, in fl uence, or activity. The subject area to which the user applies a program is the domain of the software;”
39. Domain Types 🎂 Core domain 
 🍰 Supporting sub domain 
 🧁 Generic sub domain
40. Domain Types 🎂 Core domain 
 🍰 Supporting sub domain 
 🧁 Generic sub domain 
 🥮 Utilities (infrastructure) sub domain
41. Domain Types 🎂 Core domain - Post, User, Ship 
 🍰 Supporting sub domain - Collections, Discussions 
 🧁 Generic sub domain - Votes, Comments, Seo 
 🥮 Utilities - External, ExecSQL, HandleRaceCondition
42. What is PH Code Domain
43. 🤷
44. Moderation Voting Comments Posts Collections Maker Goals Sharing Seo Discussions Ask Ship Mentors Founder Club Golden Kitty Maker Fest Topics Stories Spam Newsletter Noti fi cations Metrics Users Payments Activity Feed Jobs
45. Moderation Voting Comments Posts Collections Maker Goals Sharing Seo Discussions Ask Ship Mentors Founder Club Golden Kitty Maker Fest Topics Stories Spam Newsletter Noti fi cations Metrics Users Payments Activity Feed Jobs Core Feature Generic Context Map
46. Moderation Voting Comments Posts Collections Maker Goals Sharing Seo Discussions Ask Ship Mentors Founder Club Golden Kitty Maker Fest Topics Stories Spam Newsletter Noti fi cations Metrics Users Payments Activity Feed Jobs Core Feature Generic Context Map Utilities
47. Bounded Context “A semantic contextual boundary. This means that within the boundary each component of the software model has a speci fi c meaning and does speci fi c things.”
49. ...kinda 🙈
50. Admin Other Bounded Context Utilities Bounded Context (Domain) Models Services Jobs GraphQL Mutations Resolvers Types
51. https://www.phoenixframework.org/
52. defmodule Hello.Accounts do @moduledoc """ The Accounts context. """ import Ecto.Query, warn: false alias Hello.Repo alias Hello.Accounts.User @doc """ Returns the list of users. ## Examples iex> list_users() [%User{}, ...] """ def list_users do Repo.all(User) end ... end
53. Showcase 1
 Feature Domain
55. /app/domain/
 /app/domain/founder_club.r b /app/domain/founder_club/*.rb
56. FounderClub.join_waitlist(user:) 
 FounderClub.join(user:) FounderClub.request_access(user:, code:) FounderClub.deliver_waitlist_invite(invite:) FounderClub.plan_for(code:) 
 FounderClub.subscribe(user:, subscription_id:) FounderClub.claim_deal(user:, deal:) FounderClub.claimed_deals_by(user:) FounderClub.deals_available_to(user:) FounderClub.create_referral_code(user:, email:) FounderClub.destroy_referral_code(user:, email:) 
 FounderClub.referrals_of(user:) 
 
 FounderClub.active_subscription?(user) FounderClub.list_subscriptions 
 FounderClub.transfer_subscription(from:, to:)
57. FounderClub::Admin::DealForm 
 FounderClub::Policy 
 FounderClub::MailerInfo 🤷
58. FounderClub.admin_deal_form 
 FounderClub.policy 
 FounderClub.mail_info 🤔
59. module FounderClub extend self 
 def admin_deal_form 
 FounderClub::Admin::DealForm 
 end 
 
 def policy 
 FounderClub::Policy 
 end 
 
 def mailer_info FounderClub::MailerInfo 
 end 
 end 🤔
60. Showcase 2
 Generic Domain
61. Sharing.text_for(post) 
 Sharing.text_for(post, current_user: user) 
 Sharing.image_for(post) 
 Sharing.image_for_comment(comment, highlighted_text: 'Awesome')
62. module Sharing extend self def text_for(subject, current_user: nil) generator = FindConst.call(Sharing::Text, subject) if generator.method(:call).arity == 1 generator.call(subject) else generator.call(subject, current_user: current_user) end end def image_for(subject) generator = FindConst.call(Sharing::ImageUrl, subject) generator.call(subject) end def image_for_comment(comment, highlighted_text:) Sharing::ImageUrl:Comment.call(comment, highlighted_text: highlighted_text) end endd
63. Domain Event “A domain object that de fi nes an event (something that happens). A domain event is an event that domain experts care about.”
64. Domain Event != Event Souring
65. Kitty Event s https://github.com/producthunt/KittyEvents
66. Design Patterns 🚗 Entity 
 🚕 Value Object 
 🚙 Aggregate 🚌 Repository 🚎 Facade 🚐 Factory 🚚 Service 
 🚛 Presenter
67. Design Patterns 🚗 Entity 
 🚕 Value Object 
 🚙 Aggregate 🚌 Repository 🚎 Facade 🚐 Factory 🚚 Service 
 🚛 Presenter
68. Design Patterns 🚗 Entity 
 🚕 Value Object 
 🚙 Aggregate 🚌 Repository 🚎 Facade 🚐 Factory 🚚 Service 
 🚛 Presenter
70. https://github.com/producthunt/producthunt/tree/master/app/services/sharing 👉 https://github.com/producthunt/stacks/tree/master/backend/app/services/share
71. module Share::Subject extend self def call(subject:, current_profile: ) subject_class = subject.class.name.tr('::', '' ) share = "Share::Subjects::#{subject_class}".constantiz e share.generate subject, current_profil e end end
72. module Share extend self def message_for(subject, current_profile: nil ) subject_class = subject.class.name.tr('::', '' ) share = "Share::Subjects::#{subject_class}".constantiz e share.generate subject, current_profil e end end
73. module Share extend self def message_for(subject, current_profile: nil ) subject_class = subject.class.name.tr('::', '' ) share = "Share::Message::#{subject_class}".constantiz e share.generate subject, current_profil e end end
74. module Share extend self def message_for(subject, current_profile: nil ) share = Utils.module_for(subject, in: Share::Message ) share.generate subject, current_profil e end end 💡
76. Books
78. Whats next...
79. ... any ideas? 💡 😅