Rails 3 - trying to create polymorphic has_one association in console - ruby-on-rails-3

Question

Here's my code:
Models:
class Article < ActiveRecord::Base
attr_accessible :title, :author, :content, :imageable_attributes
has_one :image, as: :imageable, dependent: :destroy
accepts_nested_attributes_for :image, allow_destroy: true
validates_presence_of :title, :content, :author
end
class Image < ActiveRecord::Base
mount_uploader :image, ImageUploader
attr_accessible :image, :caption, :imageable_id, :imageable_type, :article_ref
validates_presence_of :image
belongs_to :imageable, :polymorphic => true
end
Here's what I've tried in console:
article = Article.create!(title: "test", content: "test", author: "test", image_attributes: {image: "test.jpg", caption: "test caption"})
This creates an Article without errors, but if I call:
article.image
I get:
=> nil
If I type in console:
article = Article.new(title: "test", content: "test", author: "test")
article.build_image(image: "test.jpg")
I get:
=> Validation failed: Image image can't be blank
Any help greatly appreciated, I'm very confused!

Answer 1

I believe it's necessary to supply the attachment itself, rather than just the path. As an example,
i = Image.new(
:image => File.join(Rails.root, "test.jpg")
)
i.image
# =>
but
i = Image.new(
:image => File.open(File.join(Rails.root, "test.jpg"))
)
i.image
# => /uploads/tmp/20120427-2155-1316-5181/test.jpg
It's not necessary to use File.open when saving using Multipart POST, though.