X-Git-Url: https://git.njae.me.uk/?a=blobdiff_plain;f=vendor%2Frails%2Factiverecord%2Flib%2Factive_record%2Fcallbacks.rb;fp=vendor%2Frails%2Factiverecord%2Flib%2Factive_record%2Fcallbacks.rb;h=42bfe34505dd9214b8f6b01d56a8ad4d9be140ea;hb=d115f2e23823271635bad69229a42cd8ac68debe;hp=0000000000000000000000000000000000000000;hpb=37cb670bf3ddde90b214e591f100ed4446469484;p=depot.git diff --git a/vendor/rails/activerecord/lib/active_record/callbacks.rb b/vendor/rails/activerecord/lib/active_record/callbacks.rb new file mode 100644 index 0000000..42bfe34 --- /dev/null +++ b/vendor/rails/activerecord/lib/active_record/callbacks.rb @@ -0,0 +1,331 @@ +require 'observer' + +module ActiveRecord + # Callbacks are hooks into the lifecycle of an Active Record object that allow you to trigger logic + # before or after an alteration of the object state. This can be used to make sure that associated and + # dependent objects are deleted when +destroy+ is called (by overwriting +before_destroy+) or to massage attributes + # before they're validated (by overwriting +before_validation+). As an example of the callbacks initiated, consider + # the Base#save call for a new record: + # + # * (-) save + # * (-) valid + # * (1) before_validation + # * (2) before_validation_on_create + # * (-) validate + # * (-) validate_on_create + # * (3) after_validation + # * (4) after_validation_on_create + # * (5) before_save + # * (6) before_create + # * (-) create + # * (7) after_create + # * (8) after_save + # + # That's a total of eight callbacks, which gives you immense power to react and prepare for each state in the + # Active Record lifecycle. The sequence for calling Base#save an existing record is similar, except that each + # _on_create callback is replaced by the corresponding _on_update callback. + # + # Examples: + # class CreditCard < ActiveRecord::Base + # # Strip everything but digits, so the user can specify "555 234 34" or + # # "5552-3434" or both will mean "55523434" + # def before_validation_on_create + # self.number = number.gsub(/[^0-9]/, "") if attribute_present?("number") + # end + # end + # + # class Subscription < ActiveRecord::Base + # before_create :record_signup + # + # private + # def record_signup + # self.signed_up_on = Date.today + # end + # end + # + # class Firm < ActiveRecord::Base + # # Destroys the associated clients and people when the firm is destroyed + # before_destroy { |record| Person.destroy_all "firm_id = #{record.id}" } + # before_destroy { |record| Client.destroy_all "client_of = #{record.id}" } + # end + # + # == Inheritable callback queues + # + # Besides the overwritable callback methods, it's also possible to register callbacks through the use of the callback macros. + # Their main advantage is that the macros add behavior into a callback queue that is kept intact down through an inheritance + # hierarchy. Example: + # + # class Topic < ActiveRecord::Base + # before_destroy :destroy_author + # end + # + # class Reply < Topic + # before_destroy :destroy_readers + # end + # + # Now, when Topic#destroy is run only +destroy_author+ is called. When Reply#destroy is run, both +destroy_author+ and + # +destroy_readers+ are called. Contrast this to the situation where we've implemented the save behavior through overwriteable + # methods: + # + # class Topic < ActiveRecord::Base + # def before_destroy() destroy_author end + # end + # + # class Reply < Topic + # def before_destroy() destroy_readers end + # end + # + # In that case, Reply#destroy would only run +destroy_readers+ and _not_ +destroy_author+. So, use the callback macros when + # you want to ensure that a certain callback is called for the entire hierarchy, and use the regular overwriteable methods + # when you want to leave it up to each descendent to decide whether they want to call +super+ and trigger the inherited callbacks. + # + # *IMPORTANT:* In order for inheritance to work for the callback queues, you must specify the callbacks before specifying the + # associations. Otherwise, you might trigger the loading of a child before the parent has registered the callbacks and they won't + # be inherited. + # + # == Types of callbacks + # + # There are four types of callbacks accepted by the callback macros: Method references (symbol), callback objects, + # inline methods (using a proc), and inline eval methods (using a string). Method references and callback objects are the + # recommended approaches, inline methods using a proc are sometimes appropriate (such as for creating mix-ins), and inline + # eval methods are deprecated. + # + # The method reference callbacks work by specifying a protected or private method available in the object, like this: + # + # class Topic < ActiveRecord::Base + # before_destroy :delete_parents + # + # private + # def delete_parents + # self.class.delete_all "parent_id = #{id}" + # end + # end + # + # The callback objects have methods named after the callback called with the record as the only parameter, such as: + # + # class BankAccount < ActiveRecord::Base + # before_save EncryptionWrapper.new("credit_card_number") + # after_save EncryptionWrapper.new("credit_card_number") + # after_initialize EncryptionWrapper.new("credit_card_number") + # end + # + # class EncryptionWrapper + # def initialize(attribute) + # @attribute = attribute + # end + # + # def before_save(record) + # record.credit_card_number = encrypt(record.credit_card_number) + # end + # + # def after_save(record) + # record.credit_card_number = decrypt(record.credit_card_number) + # end + # + # alias_method :after_find, :after_save + # + # private + # def encrypt(value) + # # Secrecy is committed + # end + # + # def decrypt(value) + # # Secrecy is unveiled + # end + # end + # + # So you specify the object you want messaged on a given callback. When that callback is triggered, the object has + # a method by the name of the callback messaged. + # + # The callback macros usually accept a symbol for the method they're supposed to run, but you can also pass a "method string", + # which will then be evaluated within the binding of the callback. Example: + # + # class Topic < ActiveRecord::Base + # before_destroy 'self.class.delete_all "parent_id = #{id}"' + # end + # + # Notice that single quotes (') are used so the #{id} part isn't evaluated until the callback is triggered. Also note that these + # inline callbacks can be stacked just like the regular ones: + # + # class Topic < ActiveRecord::Base + # before_destroy 'self.class.delete_all "parent_id = #{id}"', + # 'puts "Evaluated after parents are destroyed"' + # end + # + # == The +after_find+ and +after_initialize+ exceptions + # + # Because +after_find+ and +after_initialize+ are called for each object found and instantiated by a finder, such as Base.find(:all), we've had + # to implement a simple performance constraint (50% more speed on a simple test case). Unlike all the other callbacks, +after_find+ and + # +after_initialize+ will only be run if an explicit implementation is defined (def after_find). In that case, all of the + # callback types will be called. + # + # == before_validation* returning statements + # + # If the returning value of a +before_validation+ callback can be evaluated to +false+, the process will be aborted and Base#save will return +false+. + # If Base#save! is called it will raise a ActiveRecord::RecordInvalid exception. + # Nothing will be appended to the errors object. + # + # == Canceling callbacks + # + # If a before_* callback returns +false+, all the later callbacks and the associated action are cancelled. If an after_* callback returns + # +false+, all the later callbacks are cancelled. Callbacks are generally run in the order they are defined, with the exception of callbacks + # defined as methods on the model, which are called last. + # + # == Transactions + # + # The entire callback chain of a +save+, save!, or +destroy+ call runs + # within a transaction. That includes after_* hooks. If everything + # goes fine a COMMIT is executed once the chain has been completed. + # + # If a before_* callback cancels the action a ROLLBACK is issued. You + # can also trigger a ROLLBACK raising an exception in any of the callbacks, + # including after_* hooks. Note, however, that in that case the client + # needs to be aware of it because an ordinary +save+ will raise such exception + # instead of quietly returning +false+. + module Callbacks + CALLBACKS = %w( + after_find after_initialize before_save after_save before_create after_create before_update after_update before_validation + after_validation before_validation_on_create after_validation_on_create before_validation_on_update + after_validation_on_update before_destroy after_destroy + ) + + def self.included(base) #:nodoc: + base.extend Observable + + [:create_or_update, :valid?, :create, :update, :destroy].each do |method| + base.send :alias_method_chain, method, :callbacks + end + + base.send :include, ActiveSupport::Callbacks + base.define_callbacks *CALLBACKS + end + + # Is called when the object was instantiated by one of the finders, like Base.find. + #def after_find() end + + # Is called after the object has been instantiated by a call to Base.new. + #def after_initialize() end + + # Is called _before_ Base.save (regardless of whether it's a +create+ or +update+ save). + def before_save() end + + # Is called _after_ Base.save (regardless of whether it's a +create+ or +update+ save). + # Note that this callback is still wrapped in the transaction around +save+. For example, if you + # invoke an external indexer at this point it won't see the changes in the database. + # + # class Contact < ActiveRecord::Base + # after_save { logger.info( 'New contact saved!' ) } + # end + def after_save() end + def create_or_update_with_callbacks #:nodoc: + return false if callback(:before_save) == false + result = create_or_update_without_callbacks + callback(:after_save) + result + end + private :create_or_update_with_callbacks + + # Is called _before_ Base.save on new objects that haven't been saved yet (no record exists). + def before_create() end + + # Is called _after_ Base.save on new objects that haven't been saved yet (no record exists). + # Note that this callback is still wrapped in the transaction around +save+. For example, if you + # invoke an external indexer at this point it won't see the changes in the database. + def after_create() end + def create_with_callbacks #:nodoc: + return false if callback(:before_create) == false + result = create_without_callbacks + callback(:after_create) + result + end + private :create_with_callbacks + + # Is called _before_ Base.save on existing objects that have a record. + def before_update() end + + # Is called _after_ Base.save on existing objects that have a record. + # Note that this callback is still wrapped in the transaction around +save+. For example, if you + # invoke an external indexer at this point it won't see the changes in the database. + def after_update() end + + def update_with_callbacks(*args) #:nodoc: + return false if callback(:before_update) == false + result = update_without_callbacks(*args) + callback(:after_update) + result + end + private :update_with_callbacks + + # Is called _before_ Validations.validate (which is part of the Base.save call). + def before_validation() end + + # Is called _after_ Validations.validate (which is part of the Base.save call). + def after_validation() end + + # Is called _before_ Validations.validate (which is part of the Base.save call) on new objects + # that haven't been saved yet (no record exists). + def before_validation_on_create() end + + # Is called _after_ Validations.validate (which is part of the Base.save call) on new objects + # that haven't been saved yet (no record exists). + def after_validation_on_create() end + + # Is called _before_ Validations.validate (which is part of the Base.save call) on + # existing objects that have a record. + def before_validation_on_update() end + + # Is called _after_ Validations.validate (which is part of the Base.save call) on + # existing objects that have a record. + def after_validation_on_update() end + + def valid_with_callbacks? #:nodoc: + return false if callback(:before_validation) == false + if new_record? then result = callback(:before_validation_on_create) else result = callback(:before_validation_on_update) end + return false if false == result + + result = valid_without_callbacks? + + callback(:after_validation) + if new_record? then callback(:after_validation_on_create) else callback(:after_validation_on_update) end + + return result + end + + # Is called _before_ Base.destroy. + # + # Note: If you need to _destroy_ or _nullify_ associated records first, + # use the :dependent option on your associations. + def before_destroy() end + + # Is called _after_ Base.destroy (and all the attributes have been frozen). + # + # class Contact < ActiveRecord::Base + # after_destroy { |record| logger.info( "Contact #{record.id} was destroyed." ) } + # end + def after_destroy() end + def destroy_with_callbacks #:nodoc: + return false if callback(:before_destroy) == false + result = destroy_without_callbacks + callback(:after_destroy) + result + end + + private + def callback(method) + result = run_callbacks(method) { |result, object| false == result } + + if result != false && respond_to_without_attributes?(method) + result = send(method) + end + + notify(method) + + return result + end + + def notify(method) #:nodoc: + self.class.changed + self.class.notify_observers(method, self) + end + end +end