rails 3 polymorphic association with paperclip and multiple models

Question

I want to make polymorphic associations with paperclip, and allow my user to have one avatar and multiple images.

Attachment model:

Answer 1

I do have a project in the works that is successfully using Paperclip and polymorphic associations. Let me show you what I have, and maybe you can apply it to your project:

class Song < ActiveRecord::Base
  ...
  has_one :artwork, :as => :artable, :dependent => :destroy
  accepts_nested_attributes_for :artwork
  ...
end

class Album < ActiveRecord::Base
  ...
  has_one :artwork, :as => :artable, :dependent => :destroy
  accepts_nested_attributes_for :artwork
  ...
end

class Artwork < ActiveRecord::Base
  belongs_to :artable, :polymorphic => true
  attr_accessible :artwork_content_type, :artwork_file_name, :artwork_file_size, :artwork

  # Paperclip
  has_attached_file :artwork,
    :styles => {
      :small => "100",
      :full => "400"
    }

  validates_attachment_content_type :artwork, :content_type => 'image/jpeg'
end

the songs form and the albums form include this as a partial:

<%= f.fields_for :artwork do |artwork_fields| %>
  <%= artwork_fields.label :artwork %>

  <%= artwork_fields.file_field :artwork %>
<% end %>

don't forget to include :html => { :multipart => true } with the form

artworks_controller.rb

class ArtworksController < ApplicationController
  def create
    @artwork = Artwork.new(params[:artwork])

    if @artwork.save
        redirect_to @artwork.artable, notice: 'Artwork was successfully created.'
    else
        redirect_to @artwork.artable, notice: 'An error ocurred.'
    end
  end
end

and finally, an excerpt from songs_controller.rb:

def new
    @song = Song.new
    @song.build_artwork
end