Blog: Multiple files upload with paperclip

attached_asset.rb

class AttachedAsset < ActiveRecord::Base
  belongs_to :attachable, :polymorphic => true
  has_attached_file :asset, :styles => { :large => "800x800", :medium => "400x400>", :small => "200x200>" }
  attr_accessible :asset, :asset_file_name
end

item.rb

class Item < ActiveRecord::Base
  has_many :attached_assets, :as => :attachable
  accepts_nested_attributes_for :attached_assets, :allow_destroy => true
  attr_accessible :title, :description, :attached_assets_attributes
end

items_controller.rb

class ItemsController < ApplicationController
  def create
    @item = Item.new(params[:item])
    if @item.save
      redirect_to action: "index"
    else
      render "new"
    end
  end
end

new.html.haml

= simple_form_for(@item, html: { multipart: true }) do |f|
  = f.input :title
  = f.input :description
  = file_field_tag('item_attached_assets_asset', multiple: true, name: "item[attached_assets_attributes][][asset]")
  = f.button :submit