#62 Hacking ActiveRecord

Jul 25, 2007 | 11 minutes | Active Record

Have you ever wanted to temporarily disable all validations? Well, ActiveRecord doesn't support this, but that doesn't mean we can't add it. This episode will show you how to open up an existing class and change its behavior.

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Resources

          test_helper.rb
        
class Test::Unit::TestCase
  self.use_transactional_fixtures = true
  self.use_instantiated_fixtures  = false
  
  def disable_validation
    ActiveRecord::Base.disable_validation!
    yield
    ActiveRecord::Base.enable_validation!
  end
end

module ValidationDisabler
  def self.included(base)
    base.class_eval do
      extend ClassMethods
      alias_method_chain :valid?, :disable_check
    end
  end
  
  def valid_with_disable_check?
    if self.class.validation_disabled?
      true
    else
      valid_without_disable_check?
    end
  end
  
  module ClassMethods
    def disable_validation!
      @@disable_validation = true
    end
    
    def enable_validation!
      @@disable_validation = false
    end
    
    def validation_disabled?
      @@disable_validation ||= false
    end
  end
end

class ActiveRecord::Base
  include ValidationDisabler
end

Note there is a slight problem with how I set the default value for the class variable in the screencast. The code posted here should be correct.

Ideally I would use something like class_inheritable_accessor instead of a class variable, but I was unable to get this to work. Please comment if you have a suggestion.