Rails 5.1 API渲染JSON倍增关系

Question

With Rails 5.1.1 I have a problem where rendering JSON is somehow "doubling" the number of relationships.

There is a has_many / belongs_to relationship, nothing fancy. A "user" has many "codes". Stepping through the users_controller#update method I see the following:

Check what is coming in from the params:

(byebug) user_params['codes_attributes'].count
2

Check what is saved after @user.update(user_params) was called:

(byebug) @user.codes.count
   (0.4ms)  SELECT COUNT(*) FROM "codes" WHERE "codes"."user_id" = ?  [["user_id", 85]]
2

Lastly, a straight as_json doubles via the relationship as well:

(byebug) @user.codes.as_json.count
4

Check what is output from as_json ( to_json is the same):

(byebug) @user.as_json(include: [:friend, :codes])['codes'].count
4
(byebug) @user.codes.count
   (0.3ms)  SELECT COUNT(*) FROM "codes" WHERE "codes"."user_id" = ?  [["user_id", 85]]
2

And here we can see that somehow the number of relationships magically doubled! Any ideas?

UPDATE

I was making use of a custom function to save associations (autosave_associated_records_for_codes) which seems to have introduced the problem. I've commented it out for now but will try to revisit why exactly it was doubling things up. Once I figure out the exact cause will reply back with a solution.

Answer 1

I don't have much experience in rails, though i suggest you to try this. Iam not sure about it, but you should give it a try.

  def get_codes_count
    self.codes.count
  end

And then if you want a count then you can just do

  @user.as_json(method: :get_codes_count)