CarrierWave Uploader thats Compatible with Paperclip fields

file_uploader

class FileUploader < CarrierWave::Uploader::Base
  ### This uploader is setup for paperclip compatibility

  include CarrierWave::MiniMagick

  storage :file

  def store_dir
    "system/#{model.class.to_s.pluralize.underscore}/#{mounted_as.to_s.pluralize}/#{model_id_partition}"
  end

  def default_url
    "/img/diagrams/#{version_name}/missing.png"
  end

  def version_name
    super || :original
  end

  def full_filename(for_file)
    super(for_file).sub("#{version_name}_", '').prepend("#{version_name}/")
  end

  with_options if: :is_imageable? do
    version :thumb do
      process resize_to_fit: [50, 64]
      process convert: :jpg

      def full_filename(for_file)
        super(for_file).chomp(File.extname(super(for_file))) + ".jpg"
      end
    end

    version :preview do
      process resize_to_fit: [480, 620]
      process convert: :jpg

      def full_filename(for_file)
        super(for_file).chomp(File.extname(super(for_file))) + ".jpg"
      end
    end
  end

  # def extension_whitelist
  #   %w(jpg jpeg gif png)
  # end

  IMAGE_TYPES = ['jpg','jpeg','png','gif','tif','bmp'].freeze
  IMAGEABLE_TYPES = (IMAGE_TYPES + ['pdf']).freeze

  private

  def is_imageable?(file)
    IMAGEABLE_TYPES.include?(file.extension.downcase)
  end

  # http://over9000.org/rails/paperclip-with-more-than-32-000-attachments
  # e.g.: 1234 => "000/001/234"
  def model_id_partition
    ("%09d" % model.id).scan(/\d{3}/).join("/")
  end

end

initializer

require 'carrierwave/orm/activerecord'

CarrierWave.configure do |config|
  config.cache_dir = Rails.root.join('tmp/uploads')
end

model

class Model < ActiveRecord::Base
   mount_uploader :document, Fileuploader, mount_on: :document_file_name
end