Creating a “feed” from multiple rails models, efficiently?

Question

This is a follow up to Creating "feeds" from multiple, different Rails models. In this question, tadman suggests this method of creating a user feed of recent item

Answer 1

What I did once was, have a separate model Feed (feeds_controller) and update it in after_save callbacks to all the interesting models. So for example if you have a model Article, have an after_save callback:

def after_save
  feed = Feed.new
  feed[:model_name] = 'Article'
  feed[:item_id] = id
  feed.save
end

then, you can access the feed linearly just like any other model. The computational expense is incurred when saving the the feed, not reading from the feed.

Oh, you can also have Feed has_many :article; has_many :user, has_many :status and so forth, and then :include all those resources in the feed, and render them in views. Hope this makes sense ;-)