Save before initial save of an object - ruby-on-rails

Question

When a conversation is created, I want that conversation to have its creator automatically following it:
class Conversation < ActiveRecord::Base
belongs_to :user
has_many :followers
has_many :users, through: :followers
alias_method :user, :creator
before_create { add_follower(self.creator) }
def add_follower(user)
unless self.followers.exists?(user_id: user.id)
self.transaction do
self.update_attributes(follower_count: follower_count + 1)
self.followers.create(user_id: user.id)
end
end
end
end
However, when a user attempts to create a conversation I get a stack level too deep
. I'm creating an infinite loop, and I think this is because the before_create callback is being triggered by the self.update_attributes call.
So how should I efficiently update attributes before creation to stop this loop happening?

Answer 1

Option 1 (preferred)
Rename your column follower_count to followers_count and add:
class Follower
belongs_to :user, counter_cache: true
# you can avoid renaming the column with "counter_cache: :follower_count"
# rest of your code
end
Rails will handle updating followers_count for you.
Then change your add_follower method to:
def add_follower(user)
return if followers.exists?(user_id: user.id)
followers.build(user_id: user.id)
end
Option 2
If you don't want to use counter_cache, use update_column(:follower_count, follower_count + 1). update_column does not trigger any validations or callbacks.
Option 3
Finally you don't need to save anything at this point, just update the values and they will be saved when callback finishes:
def add_follower(user)
return if followers.exists?(user_id: user.id)
followers.build(user_id: user.id)
self.follower_count = follower_count + 1
end