cheat sheets.

Regular callbacks in ActiveRecord::Base:

  1. before_validation
  2. before_validation_on_create
  3. after_validation
  4. after_validation_on_create
  5. before_save
  6. before_create
  7. after_create
  8. after_save
  9. before_destroy
  10. after_destroy

Usage:

  Define a method:

    class Foo < ActiveRecord::Base
      def before_create
        # your code here
      end
    end

 Invoke callback with a name of a method:

    class Foo < ActiveRecord::Base
      before_create :do_stuff
    protected
      def do_stuff
        # your code here
      end
    end

  Invoke callback with a block:

    class Foo < ActiveRecord::Base
      before_create do
        def do_stuff
          # your code here
        end
      end
    end

Exceptions:

  1. after_find
  2. after_initialize 

Usage:

  Define a method:

    class Foo < ActiveRecord::Base
      def after_find
        do_stuff
      end
    end