How to paginate an eager loaded association model

Question

I have the following code :

Post.where("user_id IN [1, 2, 3, 4, 5, 6]").includes(:authors, :comments).paginate(page: params[:page], per_page: 30)

what i want here is to eager load just 8 comments per post using will_paginate, is this possible ? and how ?

Answer 1

Not a tested answer

I don't see that possible from there, but:

Comment.joins(:posts).includes(:posts).where(posts: { user_id: [1,2,3,4,5,6] })

I am not sure if joins and includes can be called together.

This would give you a relation for comments you can continue working on, and you will have eager loaded posts:

@comments = Comment.joins(:post).includes(:post).where(posts: { user_id: [1,2,3,4,5,6] })
@comments.paginate(...)

If you want to get the posts from @comments I would do this:

class Comment < ActiveRecord::Base
  def self.post_ids
    all.map(&:post_id)
  end

  def self.posts
    Post.where(id: post_ids)
  end
end

Then use and paginate it:

@posts = @comments.posts.paginate(...)