Conditional counter cache dependent on Paperclip

Question

I have a counter_culture counter that depends on whether a Paperclip attachment is defined or not:

class Post < ::ActiveRecord::Base
  belongs_to :user

  counter_culture :user, column_name: Proc.new { |p| p.media? ? 'posts_with_photo_count' : nil }
end

The issue is that the counter is not updated when the post is either updated nor destroyed.

I guess it should have something to do with Paperclip's own callback system.

score 0 · Accepted Answer · answered Oct 23 '15 at 12:53

I guessed what is happening. It's in fact due to a flow mismatch regarding the callbacks of both counter_culture and Paperclip.

Since on after_update, the attachment is not already processed when the counter condition executes, p.media? returns false and the counter is not incremented.

A similar thing happens on after_destroy, since the attachment is destroyed on before_destroy.

I came up with the following solution for this issue:

counter_culture :user, column_name: Proc.new { |p| (p.photo_file_name? || !p.photo_file_name_was.nil?)  ? 'posts_with_photo_count' : nil }

It basically considers the _file_name for creates and updates and verifies if the attachment was cleared on destroy.

Conditional counter cache dependent on Paperclip

1 Answers1