How to display image in index view - ruby-on-rails

Question

I am using carrierwave and trying to display images of products in the index view. This are my models, controllers and views
product.rb
class Product < ActiveRecord::Base
has_many :order_items
belongs_to :category, required: false
has_many :product_attachments
accepts_nested_attributes_for :product_attachments
mount_uploader :image, ImageUploader
default_scope { where(active: true) }
end
product_attachment.rb
class ProductAttachment < ApplicationRecord
mount_uploader :image, ImageUploader
belongs_to :product
end
products_controller.rb (extract)
class ProductsController < ApplicationController
def index
#products = Product.all
#order_item = current_order.order_items.new
end
def show
#product = Product.find(params[:id])
#product_attachments = #product.product_attachments.all
end
def new
#product = Product.new
#product_attachment = #product.product_attachments.build
#categories = Category.all.map{|c| [ c.name, c.id ] }
end
def create
#product = Product.new(product_params)
#product.category_id = params[:category_id]
respond_to do |format|
if #product.save
params[:product_attachments]['image'].each do |a|
#product_attachment = #product.product_attachments.create!(:image => a, :product_id => #product.id)
end
format.html { redirect_to #product, notice: 'Product was successfully created.' }
else
format.html { render action: 'new' }
end
end
end
private
def product_params
params.require(:product).permit(:name,:price, :active, :description, product_attachments_attributes:
[:id, :product_id, :image], category_attributes: [:category_id, :category])
end
end
index.html.erb
<div class="row">
<div class="col-xs-offset-1 ">
<% #products.each do |product| %>
<%= render "product_row", product: product, order_item: #order_item %>
<% end %>
</div>
_product_row.html.erb
<div class="well">
<div class="row">
<div class="container-fluid row">
<div class="col-md-5 col-lg-5 col-sm-5 col-xs-5 binder">
<br><%= image_tag product.image_url.to_s %><br><br>
</div>
<div class="col-md-4 col-lg-4 col-sm-4 col-xs-4 binder">
<h4 class="text-left"><%= product.name.split.map(&:capitalize).join(' ') %> </h4>
<h4 class="text-left"><span style="color: green"><%= number_to_currency(product.price, :unit => "€") %></span></h4>
<h4><%= link_to Category.find(product.category_id).name, category_path(product.category_id) %></h4>
<h6 class="text-left"><%= link_to 'Delete', product_path(product), method: :delete,
data: { confirm: 'Are you sure?' } %></h6><br><br>
</div>
<div class="col-md-3 col-lg-3 col-sm-3 col-xs-3 binder">
<%= form_for order_item, remote: true do |f| %>
<div class="input-group">
<%= f.number_field :quantity, value: 1, class: "form-control", min: 1 %>
<div class="input-group-btn">
<%= f.hidden_field :product_id, value: product.id %>
<%= f.submit "Add to Cart", class: "btn btn-primary text-right" %>
</div>
</div>
<% end %>
</div>
</div>
</div>
</div>
With <%= image_tag product.image_url.to_s %> the image doesn't appear. When I change it to <%= image_tag product_attachments.first.image_url.to_s %> I get the following error:
undefined local variable or method `product_attachments' for #<#<Class:0x00007f28544ccc68>:0x00007f285dd3aab8>
I am pretty new to Ruby and don't know what I am doing wrong or how to fix this. Any help would be appreciated. I am using Ruby version 2.5.1 and rails 5.2.0 on ubuntu.

Answer 1

I would expect that the following works:
<%= image_tag product.product_attachments.first.image_url.to_s %>

Answer 2

Try this:
image_tag(product.product_attachments.first.image.url.to_s)
It should work. I realized that sometimes image_url doesn't work as expected but image.url does.

Answer 3

If i understand well your snippets, the model you mount the ImageUploader is ProductAttachment (which have the attribute image) so you can remove mount_uploader :image, ImageUploader of your Product model.
The image is mounted on every product_attachments for one product. Just display the images inside the partial by iterating through product_attachments:
<% product.product_attachments.each do |attachment| %>
<%= image_tag(attachment.image.url) %>
<% end %>