Rails habtm callbacks
Is there a way to add callbacks for when an item is added to a habtm relationship?
For example, I have the following two models, User
and Role
:
# user.rb
class User; has_and_belongs_to_many :roles; end
# role.rb
class Role; has_and_belongs_to_many :users; end
I want to add a callback to the <<
method (@user << @role
), but I can't seem to find an ActiveRecord callback because there 开发者_开发问答is no model for the join table (because its a true habtm).
I'm aware that I could write a method like add_to_role(role)
, and define everything in there, but I'd prefer to use a callback. Is this possible?
Yes there is:
class User < AR::Base
has_and_belongs_to_many :roles,
:after_add => :tweet_promotion,
:after_remove => :drink_self_stupid
private
def tweet_promotion
# ...
end
def drink_self_stupid
# ...
end
end
Look for 'Association callbacks' on this page for more: http://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html
精彩评论