Paperclip: undefined method `new_record?' for nil:NilClass

Question

I get a wonderful error in a rails project. I have a controller "article.rb". I use paperclip to attach multiple images and for that I use a model "article_image". Every things are ok when I go to action new to create a new article and check for new record. I get the following error:

undefined method `new_record?' for nil:NilClass

articles_controller.rb

    class ArticlesController < ApplicationController

    before_action :confirm_logged_in
    def index
        @articles= Article.paginate(page: params[:page],per_page:15).sorted

    end

    def new
        @articles=Article.new()
        3.times {@articles.article_images.build}
    end

    def create
        @articles= Article.new(article_params)
        if @articles.save
            flash[:notice]="article created successfully"
            redirect_to(:action =>"index")
        else 
            render("new")
        end
    end

    def show
        @articles= Article.find(params[:id])
    end

    def edit
        @articles= Article.find(params[:id])
        4.times {@articles.article_images.build}
    end

    def update
        @articles=Article.find(params[:id])
        if @articles.update_attributes(article_params)
            flash[:notice]="Article updated successfully"
            redirect_to(:action=>"show",:id=>@articles.id)
        else
            render("edit")
        end
    end

    def delete
        @articles= Article.find(params[:id])
    end

    def destroy
        @articles=Article.find(params[:id])
        @articles.destroy
        redirect_to(:action => 'index')
    end

    private
    def article_params
        params.require(:articles).permit(:title,:position,:visible,:body,:created_at, article_imgs_attributes: [:photo])
    end
end

models/article.rb

class Article < ActiveRecord::Base

    has_many :article_images, :dependent => :destroy
    accepts_nested_attributes_for :article_images
    belongs_to :admin_user   
   end

models/article_image.rb

    class ArticleImage < ActiveRecord::Base
    belongs_to :article
    has_attached_file :photo, :styles => {:medium => "300x300>", :thumb => "100x100#"}
    validates_attachment_presence :photo
    validates_attachment_size :photo, :less_than => 5.megabytes
    validates_attachment_content_type :photo, :content_type => /\Aimage\/.*\Z/
end

view/article/new/html.erb

    <div class="page-header"><h1>Articles</h1></div>
<%= link_to("back to article",{:action =>"index"}, :class =>"action index") %>

<%= form_for(:articles, :html =>{:multipart => true}, :url=>{:action =>'create'}) do |f| %> 
    <%= f.fields_for :article_imgs do |builder| %>
        <% if builder.object.new_record? %>
        <p>
          <%= builder.label :photo, "Image File" %>
          <%= builder.file_field :photo %>
        </p>

        <% end %> 
      <% end %>
  <% end %>


 <div class="form-submit">
    <%= submit_tag("create article") %>
 </div>
 <% end %>
</div>

getting error in

>    <% if builder.object.new_record? %>

I use 'paperclip', '~> 4.2.1' in this project. Any one can help me to find the problem?

One of the results from calling fields_for returns nil when object is called. That's where your error comes from - nil doesn't have a new_record? method. — fzzfzzfzz
What is the purpose of this line <% if builder.object.new_record? %> what you are trying to achieve? — Pavan

Prashant4224 Prashant4224 · Accepted Answer · 2015-05-30T20:53:21

Change in articles_controller.rb

def article_params
   params.require(:articles).permit(:title,:position,:visible,:body,:created_at, article_images_attributes: [:photo])
end

And in views/article/new/html.erb

<%= f.fields_for :article_images do |builder| %>

I hope it works

Paperclip: undefined method `new_record?' for nil:NilClass

1 Answers