Question

I want to use an ActiveModel callback to be called after an object has been voted on, the issue is that the gem I’m using (voteable_mongo) to make the model votable doesnt provide like a vote model or callback in my app, so how can I create a callback for it?

set_callback(:vote, :before) do |object|
  object.do_something
end

Obviously that vote action I made up, but the gem I’m using has this method, how would you properly extend this method to trigger a callback?

Answer 1

Taking the plugin example as source here’s what you could do:

class Post
  include Mongoid::Document
  include Mongo::Voteable
  extend ActiveModel::Callbacks

  define_model_callbacks :vote

  # set points for each vote
  voteable self, :up => +1, :down => -1

  def vote(options, value = nil)
    _run_vote_callbacks do
      super( options, value )
    end
  end

end

I did not run this code so I am not sure if this is going to work correctly or not, but in the worst case you could alias the vote method using alias_method_chain or just copy and paste the source to inside the _run_vote_callbacks block (really, really ugly, but it’s a solution anyway).

EDIT

This could also be done using alias_method_chain, if the code above does not work:

class Post
  include Mongoid::Document
  include Mongo::Voteable
  extend ActiveModel::Callbacks

  define_model_callbacks :vote

  # set points for each vote
  voteable self, :up => +1, :down => -1

  alias_method_chain :vote, :callback

  def vote_with_callback(options, value = nil)
    _run_vote_callbacks do
      vote_without_callbacks( options, value )
    end
  end

end