Module: ActiveSupport::Callbacks
- Defined in:
- lib/active_support/callbacks.rb
Overview
Callbacks are hooks into the lifecycle of an object that allow you to trigger logic before or after an alteration of the object state.
Mixing in this module allows you to define callbacks in your class.
Example:
class Storage
include ActiveSupport::Callbacks
define_callbacks :before_save, :after_save
end
class ConfigStorage < Storage
before_save :saving_message
def
puts "saving..."
end
after_save do |object|
puts "saved"
end
def save
run_callbacks(:before_save)
puts "- save"
run_callbacks(:after_save)
end
end
config = ConfigStorage.new
config.save
Output:
saving...
- save
saved
Callbacks from parent classes are inherited.
Example:
class Storage
include ActiveSupport::Callbacks
define_callbacks :before_save, :after_save
before_save :prepare
def prepare
puts "preparing save"
end
end
class ConfigStorage < Storage
before_save :saving_message
def
puts "saving..."
end
after_save do |object|
puts "saved"
end
def save
run_callbacks(:before_save)
puts "- save"
run_callbacks(:after_save)
end
end
config = ConfigStorage.new
config.save
Output:
preparing save
saving...
- save
saved
Defined Under Namespace
Modules: ClassMethods Classes: Callback, CallbackChain
Class Method Summary collapse
Instance Method Summary collapse
-
#run_callbacks(kind, options = {}, &block) ⇒ Object
Runs all the callbacks defined for the given options.
Class Method Details
.included(base) ⇒ Object
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# File 'lib/active_support/callbacks.rb', line 205 def self.included(base) base.extend ClassMethods end |
Instance Method Details
#run_callbacks(kind, options = {}, &block) ⇒ Object
Runs all the callbacks defined for the given options.
If a block is given it will be called after each callback receiving as arguments:
* the result from the callback
* the object which has the callback
If the result from the block evaluates to false, the callback chain is stopped.
Example:
class Storage
include ActiveSupport::Callbacks
define_callbacks :before_save, :after_save
end
class ConfigStorage < Storage
before_save :pass
before_save :pass
before_save :stop
before_save :pass
def pass
puts "pass"
end
def stop
puts "stop"
return false
end
def save
result = run_callbacks(:before_save) { |result, object| result == false }
puts "- save" if result
end
end
config = ConfigStorage.new
config.save
Output:
pass
pass
stop
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# File 'lib/active_support/callbacks.rb', line 297 def run_callbacks(kind, = {}, &block) # self.class.send("#{kind}_callback_chain") # self.class.send("#{kind}_callback_chain").run(self, , &block) end |