Model has_many PaperclipModel. I have error "undefined method `img'"

Question

I installed gem Paperclip, created two models

class Image < ActiveRecord::Base
  belongs_to :pizzerium
  attr_accessible :img, :pizzerium_id, :alt
    has_attached_file :img, :styles => { :medium => "300x300>", :thumb => "100x70>" }, :default_url => "/images/:style/missing.png"
  self.per_page = 6
end

And Pizzerium

class Pizzerium < ActiveRecord::Base
  has_many :images
  accepts_nested_attributes_for :images, allow_destroy: true
  attr_accessible :description, :name, :url, :city, :meta_tag, :text_shedule, :time_begin, :time_end, :week_begin, :week_end
end

If i write in controller this code:

@pizzerium = Pizzerium.where("city = ? AND url = ?", params[:city], params[:pizza]).first
@images = @pizzerium.images.all

and this code in view:

<%= image_tag @images.first.img.url(:medium) %>

it's works, but if i trying

@pizzs = Pizzerium.where("city = ?", params[:city]).paginate(:page => params[:page])

or

@pizzs = Pizzerium.includes(:images).where("city = ?", params[:city]).paginate(:page => params[:page])


<% @pizzs.each do |pizzerium| %>
<%= image_tag pizzerium.images.first.img.url %>
<% end %>

I see error:

NoMethodError in General#index

Showing /home/wwju/rails/pizza/app/views/general/index.html.erb where line #14 raised:

undefined method `img' for nil:NilClass

in rails console:

pizzs = Pizzerium.includes(:images).all
  Pizzerium Load (31.6ms)  SELECT "pizzeria".* FROM "pizzeria" 
  Image Load (10.3ms)  SELECT "images".* FROM "images" WHERE "images"."pizzerium_id" IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 32)
 => [#<Pizzerium id: 1, name: "Пицца-шляпа...
...

pizzs.first.images.first.img
 => /system/images/imgs/000/000/017/original/02.jpg?1369309592 

1.9.3p429 :027 > pizzs.each do |p|
1.9.3p429 :028 >     p.images.first.img
1.9.3p429 :029?>   end
NoMethodError: undefined method `img' for nil:NilClass
    from (irb):28:in `block in irb_binding'

(If you find any mistakes, please, let me know, I'm working to improve my English.)

Sachin R Sachin R · Accepted Answer · 2013-05-27T11:37:53

I think pizzerium.images is nil. No image associated with pizzerium object.

add check pizzerium.images? 
<%= image_tag pizzerium.images.first.img.url if pizzerium.images? %>

Model has_many PaperclipModel. I have error "undefined method `img'"

1 Answers