Class: ActiveRecord::Reactor

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/active_record/reactor.rb,
lib/active_record/reactor/version.rb,
lib/active_record/reactor/callbacks.rb

Overview

Active Record Reactors

ActiveRecord Reactors provide a defined way to react on default or custom ActiveRecord::Callbacks. You may think of a Reactor as an Observer which is explicitly registered with one or more models, and does not define any magic methods.

When a Reactor is registered with a model, it checks which of the model’s callbacks are also defined as reactor instance methods, and adds these to the model’s callback chain.

Reactor callbacks will always return true, therefore it is not possible to halt the callback chain from a reactor. If you want to do that, you should consider moving the code inside the model.

Examples:

class YummyReactor < ActiveRecord::Reactor
  after_create(record)
    puts "Yummy, #{record.color} #{record.class.name} created!" if record.is_a?(Fruit)
  end
end

class Fruit < ActiveRecord::Base
  attr_accessor :peel

  # Connect your model to the reactor
  reactor :yummy

  def color; end
end

Reactor scramming

Reactors can be halted temporarily using the scram class method.

class Apple < Fruit; end

YummyReactor.scram do
  Apple.create! # do not trigger reaction on YummyReactor
end

Defined Under Namespace

Modules: Callbacks

Constant Summary collapse

VERSION = 
'1.5.0'

Class Method Summary collapse

Class Method Details

.callbacks ⇒ Object

:nodoc:



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# File 'lib/active_record/reactor.rb', line 49

def callbacks # :nodoc:
  (self.public_instance_methods - ActiveRecord::Reactor.public_instance_methods).grep(/\A(before|around|after)_.+/)
end

.scram(&block) ⇒ Object

Stops all reactions while inside the (required) block.



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# File 'lib/active_record/reactor.rb', line 58

def scram(&block)
  previously_scrammed = nil
  mutex.synchronize do
    previously_scrammed = @scrammed
    @scrammed = true
  end
  yield
ensure
  mutex.synchronize { @scrammed = previously_scrammed }
end

.scrammed? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/active_record/reactor.rb', line 53

def scrammed? # :nodoc:
  !!@scrammed
end