CODEWITHSUNDEEP
ruby-on-railsruby-on-rails-4activerecordpagination
Bryan Coxwell
Bryan Coxwell

Reputation: 119

Using will_paginate with a has_many relationship in Rails 4

I've got the following models in my Rails app:

class Post < ActiveRecord::Base
  belongs_to :user
  has_many :pictures, :dependent => :destroy
end


class Picture < ActiveRecord::Base
  belongs_to :post
  has_many :comments
  has_attached_file :image, styles: { medium: "800x800>", thumb: "225x225#" }
  validates_attachment_content_type :image, :content_type => ["image/jpg","image/jpeg","image/png"]
end

So a Post has_many Pictures. On my Post#index view, I use the following code to iterate through the posts and display the thumbnail for each of their pictures:

<% @posts.each do |post| %>
  <% post.pictures.each do |picture| %>
      <li>
        <%= link_to image_tag(picture.image.url(:thumb)), picture_path(picture)%>
      </li>
<% end %>

In order to limit the number of pictures displayed on each page, I'm attempting to implement pagination by using the following code in my Posts controller:

@pictures = @posts.pictures.paginate(:per_page => 5, :page => params[:page])

This gives the following error:

undefined method `pictures' for #<Post::ActiveRecord_Relation:0x007fc960f698a8

What am I doing wrong here? How could I fix this?

Also, I know it seems like it would be easier to just use the Pictures#index page, but I need this to work for other reasons.

Thanks!!

Upvotes: 0

Views: 849

Answers (1)

Unixmonkey
Unixmonkey

Reputation: 18784

@posts is a relation (array-like object), and it doesn't have a method named pictures.

I'm not sure why you are paginating the pictures attached to each post on an index view, but you might be doing a carousel or something, so it may be valid, but if that's the case, you'll need to paginate in the view (or build a more complex data structure in your controller):

<% @posts.each do |post| %>
  <% post.pictures.paginate(:per_page => 5, page => params["post_#{post.id}_pictures_page"]).each do |picture| %>
    <li>
      <%= link_to image_tag(picture.image.url(:thumb)), picture_path(picture)%>
    </li>
  <% end %>
<% end %>

Upvotes: 1

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