CODEWITHSUNDEEP
ruby-on-railsruby
Abeid Ahmed
Abeid Ahmed

Reputation: 355

Rails counter_cache on has_many through

I am using the counter_culture gem to cache my counts. Here are the models:

User model

has_many :memberships, dependent: :destroy

Membership model

has_many :authorables, dependent: :destroy
has_many :posts, through: :authorables

Post model

has_many :authorables, dependent: :destroy
has_many :authors, through: :authorables, source: :membership

Authorable model

belongs_to :membership
belongs_to :post

counter_culture :post, column_name: "authors_count"

As you can see, I am caching the authors_count on the post model.

When I update the post, post.update(authors: [membership]) the counter increments by 1, but when I try and remove the authors post.update(authors: []), the counter does not decrement.

Is there a way to fix it?

Upvotes: 0

Views: 362

Answers (1)

zhisme
zhisme

Reputation: 2800

Short answer is no. You cannot use post.update(authors: []) and trigger callbacks.

counter_culture gem that you provided builds its functionality on top of rails callbacks execution, I pointed in that url code which does it.

post.update(authors: []) this code doesn't trigger ActiveRecord callbacks.
Neither this one post.authors.find(1).delete.

So in order to trigger your callbacks and update counter_cache column, you will need to write some function that will resolve authors and trigger destroy

Consider this

some_conditions = { id: [1,2,3] }

post.authors.where(some_conditions).each(&:destroy)

For further reading you refer to this well-described answer about ActiveRecord callbacks

Upvotes: 1

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