Callbacks¶
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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 fires the callback of the document that the persistence action was executed on. This is that Mongoid aims to support large hierarchies and to handle optimized atomic updates callbacks can’t be firing all over 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.
Callbacks are coming from Active Support, so you can use the new syntax as well:
Relation Callbacks¶
Mongoid has a set of callbacks that are specific to collection based relations - these are:
after_add
after_remove
before_add
before_remove
Each time a document is added or removed from any of the following relations,
the respective callbacks are fired: embeds_many
,
has_many
, and has_and_belongs_to_many
.
Relation Callbacks are specified as an option on the relation. The element added/removed is the parameter to the method you call via the callback. Example: