Callbacks
On this page
Mongoid implements many of the ActiveRecord callbacks.
Document Callbacks
Mongoid supports the following callbacks for documents:
after_initialize
after_build
before_validation
after_validation
before_create
around_create
after_create
after_find
before_update
around_update
after_update
before_upsert
around_upsert
after_upsert
before_save
around_save
after_save
before_destroy
around_destroy
after_destroy
Callbacks are available on any document, whether it is embedded within another document or not. Note that to be efficient, Mongoid only invokes the callback on the document that the persistence action was executed on. This enables Mongoid to support large hierarchies and to handle optimized atomic updates efficiently (without invoking callbacks throughout the document hierarchy).
Note that using callbacks for domain logic is a bad design practice, and can lead to unexpected errors that are hard to debug when callbacks in the chain halt execution. It is our recommendation to only use them for cross-cutting concerns, like queueing up background jobs.
class Article include Mongoid::Document field :name, type: String field :body, type: String field :slug, type: String before_create :send_message after_save do |document| # Handle callback here. end protected def send_message # Message sending code here. end end
Callbacks are coming from Active Support, so you can use the new syntax as well:
class Article include Mongoid::Document field :name, type: String set_callback(:create, :before) do |document| # Message sending code here. end end
Association Callbacks
Mongoid has a set of callbacks that are specific to associations - these are:
after_add
after_remove
before_add
before_remove
Each time a document is added or removed from any of the following
associations, the respective callbacks are invoked: embeds_many
,
has_many
and has_and_belongs_to_many
.
Association callbacks are specified as options on the respective association. The document added/removed will be passed as the parameter to the specified callback. Example:
class Person include Mongoid::Document has_many :posts, after_add: :send_email_to_subscribers end def send_email_to_subscribers(post) Notifications.new_post(post).deliver end