Rails and Paperclip with nested models: uploads from form not working

Question

I'm currently trying to make a photo gallery application where photos are only accessible through a gallery interface. Gallery => has_many :photos, Photo => belongs_to :gallery. All of this is working fine.

However, now I'm trying to give my photos an attached file :image. I did everything Neath says in his tutorial, and I've just added validates_attachment_presence :image. Before the validation, the photo model was working fine except that after saving one with an image, the image never showed up. Now, with the validation, after selecting an image to upload, I'm getting a :flash =>

1 error prohibited this photo from being saved

There were problems with the following fields:

    * Image file name must be set.

So what's going on here? Relevant code below:

models/photo

 class Photo < ActiveRecord::Base
    attr_accessible :gallery_id, :name, :rating

    belongs_to :gallery
    validates_associated :gallery

    has_attached_file :image
    validates_attachment_presence :image

  end

views/photos/_form.html.erb

<% form_for [@gallery, @photo], :html => { :multipart => true } do |f| %>
  <%= f.error_messages %>
  <p>
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </p>
  <p>
    <% if @photo.image? %>
      <%= image_tag @photo.image.url %><br />
      <%= link_to @photo.image.url, @photo.image.url %>
    <% end %>
    <%= f.label :image %><br />
    <%= f.file_field :image %>
  </p>
  <p><%= f.submit %></p>
<% end %>

models/gallery.rb

class Gallery < ActiveRecord::Base
  attr_accessible :name, :user_id, :shoot_date

  # destroy all photos when a gallery is destroyed
  has_many :photos, :dependent => :destroy

end

I think I've set up the multipart form correctly, and I think I've had this problem before when I tried a paperclip model without nesting models. Am I missing something?

Update: here is the Mongrel output form the attempted upload transaction:

Processing PhotosController#update (for 127.0.0.1 at 2010-12-05 14:19:29) [PUT]
  Parameters: {"photo"=>{"name"=>"blah", "image"=>#<File:/tmp/RackMultipart20101205-2909-wo2g7z-0>}, "commit"=>"Save changes", "id"=>"10", "gallery_id"=>"3"}
  Gallery Columns (0.6ms)   SHOW FIELDS FROM `galleries`
  Gallery Load (0.1ms)   SELECT * FROM `galleries` WHERE (`galleries`.`id` = 3) 
  Photo Columns (0.7ms)   SHOW FIELDS FROM `photos`
  Photo Load (0.1ms)   SELECT * FROM `photos` WHERE (`photos`.`id` = 10 AND (`photos`.gallery_id = 3)) 
WARNING: Can't mass-assign these protected attributes: image
  SQL (0.1ms)   BEGIN
  CACHE (0.0ms)   SELECT * FROM `galleries` WHERE (`galleries`.`id` = 3) 
  SQL (0.1ms)   ROLLBACK
Rendering template within layouts/application
Rendering photos/edit
Rendered photos/_form (64.1ms)
Completed in 83ms (View: 67, DB: 2) | 200 OK [http://localhost/galleries/3/photos/10]

Josh Kovach Josh Kovach · Accepted Answer · 2010-12-05T19:43:00

Figured it out. Threw the mongrel output into google and here we go:

http://railsforum.com/viewtopic.php?id=35544

Basically, they forget to tell you to add :image to the attr_accessible listing.

Photo model changed to 
class Photo < ActiveRecord::Base
    attr_accessible :gallery_id, :name, :rating, :image

    belongs_to :gallery
    validates_associated :gallery

    has_attached_file :image
    validates_attachment_presence :image

  end

Rails and Paperclip with nested models: uploads from form not working

models/photo

views/photos/_form.html.erb

models/gallery.rb

1 Answers