ActiveRecord Callbacks - RORLab Season 3-5

Transcript

1. Active Record Callbacks Ror lab. season 3 - the 5th round - April 27th, 2013 ChangHoon Jeong(@seapy) 13֙ 4ਘ 27ੌ షਃੌ
2. Contents • The Object Life Cycle • Validations Overview • Validation Helpers • Common Validation Options • Conditional Validation • Custom Validations • Working with Validation Errors • Displaying Validation Errors in the View • Callbacks Overview • Available Callbacks • Running Callbacks • Skipping Callbacks • Halting Execution • Relational Callbacks • Conditional Callbacks • Callback Classes • Observers • Transaction Callbacks Validations Callbacks 13֙ 4ਘ 27ੌ షਃੌ
3. Life-cycle of Objects DB 13֙ 4ਘ 27ੌ షਃੌ
4. Life-cycle of Objects Active Record M odel DB 13֙ 4ਘ 27ੌ షਃੌ
5. Life-cycle of Objects Object Create Save Update Delete Active Record M odel DB 13֙ 4ਘ 27ੌ షਃੌ
6. Life-cycle of Objects Object Create Save Update Delete Validation load Active Record M odel DB 13֙ 4ਘ 27ੌ షਃੌ
7. Callbacks • Methods : protected or private • Before or after certain moments of an object’s life cycle • 6 events : create, save, update, delete, validate, load • Register using a macro-style class method ★ as an ordinary method or ★ supply as a block 13֙ 4ਘ 27ੌ షਃੌ
8. As Ordinary Methods class User < ActiveRecord::Base validates :login, :email, :presence => true before_validation :ensure_login_has_a_value protected def ensure_login_has_a_value if login.nil? self.login = email unless email.blank? end end end Macro-style class methods : 13֙ 4ਘ 27ੌ షਃੌ
9. A Block class User < ActiveRecord::Base validates :login, :email, :presence => true before_create do |user| user.name = user.login.capitalize if user.name.blank? end end Macro-style class methods : 13֙ 4ਘ 27ੌ షਃੌ
10. Available Callbacks ★Creating an Object • before_validation • after_validation • before_save • around_save • before_create • around_create • after_create • after_save ★Updating an Object • before_validation • after_validation • before_save • around_save • before_update • around_update • after_update • after_save ★Destroying an Object • before_destroy • around_destroy • after_destroy Save Destroy Create Update Validation DB 13֙ 4ਘ 27ੌ షਃੌ
11. After_find > After_initialize class User < ActiveRecord::Base after_initialize do |user| puts "You have initialized an object!" end after_find do |user| puts "You have found an object!" end end >> User.new You have initialized an object! => #<User id: nil> >> User.first You have found an object! You have initialized an object! => #<User id: 1> 13֙ 4ਘ 27ੌ షਃੌ
12. Methods Triggering Callbacks • create • create! • decrement! • destroy • destroy_all • increment! • save • save! • save(:validate =>false) • toggle! • update • update_attribute • update_attributes • update_attributes! • valid? ‘after_find’ callback • all • first • find • find_all_by_attribute • find_by_attribute • find_by_attribute! • last 13֙ 4ਘ 27ੌ షਃੌ
13. Methods Skipping Callbacks • decrement • decrement_counter • delete • delete_all • find_by_sql • increment • increment_counter • toggle • touch • update_column • update_all • update_counters 13֙ 4ਘ 27ੌ షਃੌ
14. Methods Calling Callbacks Methods Skipping Callbacks create create! decrement! decrement / ~_counter destroy delete destroy_all delete_all increment! increment / ~_counter save save! save(false) toggle! toggle update update_attribute update_column update_attributes update_all update_attributes! update_counters valid? find_by_sql touch 13֙ 4ਘ 27ੌ షਃੌ
15. Halting Execution •Queue ★ validations for model ★ registered callbacks ★ database operations • Wrapped in a Transaction ★ before_ callbacks : false or exception > stopped > ROLLBACK ★ after_ callbacks : exception > stopped > ROLLBACK 13֙ 4ਘ 27ੌ షਃੌ
16. Relational Callbacks 13֙ 4ਘ 27ੌ షਃੌ
17. Conditional Callbacks • As with validations ★ Using :if and :unless with a Symbol ★ Using :if and :unless with a String ★ Using :if and :unless with a Proc 13֙ 4ਘ 27ੌ షਃੌ
18. Conditional Callbacks as a symbol as a string as a Proc * multiple conditions possible! 13֙ 4ਘ 27ੌ షਃੌ
19. 감사합니다.
20. public/protected/private class public protected private class public protected private parent child private_method http://stackoverflow.com/questions/4495078/protected-and-private-methods-in-rails (self.)protected_method 13֙ 4ਘ 27ੌ షਃੌ