Dirty Associations¶ ↑

This plugin adds dirty-attribute-like methods for your model’s associations. The usage is very similar to the dirty objects behavior in Rails, except that due to the high database-overhead of the initialization process, you have to explicitly enable this functionality. Once enabled, you get the following methods for specified collection associations (one-to-many, many-to-many):

collection_changed?

Returns true if the association collection has changed.

collection_added?

Returns true if new records have been added to the association collection.

collection_removed?

Returns true if records have been removed from the association collection.

collection_added

Returns an array of associated objects that have been added to this collection.

collection_removed

Returns an array of associated objects that have been removed from the collection, if they still exist. This will not raise any exceptions if any objects no longer exist, it just won’t return them.

collection_were

Returns an array of the association’s objects as they were at the start of association tracking.

collection_singular_ids_changed?

Returns true if the association collection has changed.

collection_singular_ids_added?

Returns true if new records have been added to the association collection.

collection_singular_ids_removed?

Returns true if records have been removed from the association collection.

collection_singular_ids_added

Returns an array of associated objects’ ids that have been added to the collection.

collection_singular_ids_removed

Returns an array of associated objects’ ids that have been removed from the collection.

collection_singular_ids_were

Returns an array of the associated objects’ ids as they were at the start of association tracking.

(Note: collection is replaced with name of the tracked association.)

For singular associations (one-to-one), you get these methods:

association_changed?

Returns true when the association has changed.

association_added?

Returns true if an object was added to a previously empty association.

association_removed?

Returns true if an object was removed from the association, leaving it empty.

association_was

Returns the original object of the association. nil if it no longer exists.

association_id_changed?

Returns true if the association object has changed.

association_id_added?

Returns true if an object was added to a previously empty association.

association_id_removed?

Returns true if an object was removed from the association, leaving it empty.

association_id_was

Returns the original association object’s id.

association_id

Returns the current association object’s id.

(Note: association is replaced with name of the tracked association.)

And all associations get the following method:

associations_changed?

Returns true if any of the tracked associations have changed.

Installation¶ ↑

Currently, this only exists as a plugin. You can install it with:

script/plugin install git://github.com/daphonz/dirty_associations.git

Example¶ ↑

You must specify which associations you would like to make dirty in your model:

class Task < ActiveRecord::Base
  has_and_belongs_to_many :keywords
  has_many :blocking_tasks
  belongs_to :user
  keep_track_of :keywords, :user
end

You specify the scope in which you’ll track the changes to the associations by calling enable_dirty_associations on the instantiated model object, which accepts a block. All modifications you make to the object’s associations that fall within this block statement are recorded. This record persists throughout the block, but not outside of it:

task = Task.first
task.enable_dirty_associations do

  task.associations_changed? # false
  task.keyword_ids_changed?  # false

  task.keywords << Keyword.first
  task.keywords << Keyword.last

  task.keyword_ids_changed?  # true
  task.keyword_ids_removed?  # false
  task.keyword_ids_added?    # true
  task.keyword_ids_added     # [30,450]
  task.keywords_added        # ...collection of keyword objects that were added...
  task.keyword_ids_removed   # []

  task.create_user(:name => "Joey Joe Joe Jr.")

  task.user_changed?         # true
  task.user_was              # ...original user object...

end

task.associations_changed?   # false

Copyright © 2010 Casey Dreier, released under the MIT license.