Callbacks

Declaring Callbacks

To declare callbacks, NoBrainer follows the same calling convention as other ORMs as it reuses the ActiveModel callback logic. Typically:

class Model
  include NoBrainer::Document
  field :alive, :type => Boolean

  before_save { puts "going to save!" }
  after_save :say_hello, :if => :alive?

  def say_hello
    puts 'hello'
  end
end

Differences with other ORMs

NoBrainer does not stick to the traditional callback implementation. The callback behavior in NoBrainer differs in three ways compared to most ORMs:

1. Returning false in a before_* callback does not halt the chain. This way you will not halt the chain by mistake when using with boolean attributes. If your intention is to halt the chain, you can always raise an exception, or add an error to the instance.errors array in the case of a before_validation callback.

2. The initialize callbacks are also triggered during reload.

Orders of Callbacks

When a document is created:

• uniqueness validations locks are acquired
• before_validation
• validations are performed
• after_validation
• before_save
• before_create
• document is inserted
• uniqueness validations locks are released
• after_create
• after_save

When a document is updated:

• uniqueness validations locks are acquired
• before_validation
• validations are performed
• after_validation
• before_save
• before_update
• document is updated
• uniqueness validations locks are released
• after_update
• after_save

When an existing document is destroyed:

• before_destroy
• document is deleted
• after_destroy

When a document is initialized with new, or reinitialized with reload:

• before_initialize
• document is (re-)initialized
• after_initialize

When a document is fetched from the database:

• before_initialize
• document is initialized
• after_initialize
• after_find

The after_find callback will not be triggered again when calling reload on a model.

around_* callbacks are available as usual.