Павел Габриэль (Ruby/Rails разработчик, Agile-тренер, коуч) Доклад: ActiveRecord Callbacks. Готовим правильно.

1. ActiveRecord::Callbacks
Готовим правильно
Павел Габриель / @alovak

2. AR::Callbacks
before_create / save / update / validate
after_*

4. Что не так с AR::Callbacks?

5. “That’s a total of twelve callbacks,
which gives you immense power
to react and prepare for each state
in the ActiveRecord life cycle.”
— active_record/callbacks.rb

11. “That’s Ruby, which gives you
immense power to do, you know,
pretty much anything, ever”
— Ernie Miller

12. Google
“Are ActiveRecord Callbacks Any Good?”
“ActiveRecord Callbacks are Unreasonable”
“Rails, callbacks, workers, and the race you
never expected to lose”

13. “ActiveRecord's Callbacks
Ruined My Life”

19. В чем же проблема?

20. Проблема? 

21. Single Responsibility Principle

22. “A class should do the smallest
possible useful thing; that is,
it should have
a single responsibility.”
— Sandi Metz

23. SRP Violation
К лишнему весу ..

24. SRP Violation
К усложнению кода

25. SRP Violation
К сложным тестам
Невозможности повторного
использования
И т.д.

26. Варианты решений

27. Вариант с Dependency
Injection

33. Вариант с Service

37. Вариант с Events/Signals

42. ActiveSupport::Notifications

45. Wisper (gem)

48. • Минимизируйте зависимости с
помощью Dependency Injection
• Объединяйте несколько моделей в
Service
• Используйте Events/Signals

49. “Rails makes it natural and easy to build
large, well-designed OOP systems.”
— ????????

50. “Rails makes it natural and easy to build
large, well-designed OOP systems.”
— Nobody

51. Rails has no brain;
use your own!

52. Спасибо!
alovak@gmail.com