What is the recommended way to add custom scopes and other stuff to the Activity model?

[oboxodo]

It's not clear to me from the documentation and just trying to re-open the class is proving difficult because of its "special" inheriting scheme (I assume).

I'm needing to add specific belongs_to relationships per trackable type to be able to do some deep joins. I'm using this "hack" to do joins on polymorphic relationships which works pretty well.

So from what I see in the wiki here, I assume your recommendation would be to create an app/models/activity.rb file and do something like:

PublicActivity::Activity.class_eval do
  # These are hacks to be able to use `joins` on the `trackable` polymorphic association.
  # Based on: http://stackoverflow.com/a/16124295
  belongs_to :post, -> { where(activities: { trackable_type: "Post" }) }, foreign_key: "trackable_id"
  belongs_to :comment, -> { where(activities: { trackable_type: "Comment" }) }, foreign_key: "trackable_id"
  belongs_to :project, -> { where(activities: { trackable_type: "Project" }) }, foreign_key: "trackable_id"

  scope :by, -> (user) { where(owner: user) }

  def self.most_recent
    order(:updated_at).last
  end
end

Can you confirm this is the best/expected way to do it or can you suggest a more "official" way?

[pokonski]

@oboxodo yeah this is the solution that worked for everyone. Inheriting is not recommended as your class won't be used by P_A.

[klappradla]

I use a similar approach to be able to eager load different associations for different types of trackables in one query:

PublicActivity::Activity.class_eval do
  belongs_to :post, -> { includes(:activities).where(activities: { trackable_type: 'Post' }) }, foreign_key: :trackable_id
  belongs_to :meeting, -> { includes(:activities).where(activities: { trackable_type: 'Meeting' }) }, foreign_key: :trackable_id
end

But, @oboxodo , stuff like that for me only works when putting the code into config/initializers/public_activity.rb. Does it truly work with a model file for you?

[CEB-21]

@klappradla Same here. I can can also confirm this only worked for me when this file is in config/initializers/public_activity.rb.