gistfile1.txt

# Monkeypatch paperclip to handle local file attachment. Didn't add this to
# the class itself as we only need local loading during the population
AssetItem.class_eval do
  require 'open-uri'

  attr_accessor :source_filename, :source_url, :source_path, :existing_cache_file, :new_cache_file

  before_validation :import_source_file, :if => :source_filename_provided?

  private

  def source_filename_provided?
    !self.source_filename.blank?
  end

  def import_source_file
    create_missing_folders
    do_download_remote_file unless existing_cache_file
    self.item = do_import_local_file
  end

  def do_import_local_file
    io = Paperclip::Tempfile.new(source_filename)
    io.write existing_cache_file.read unless existing_cache_file.nil?
    io.size > 0 ? io : nil
  end

  def do_download_remote_file
    uri = URI.parse(remote_url)
    Net::HTTP.start(uri.host) do |http|
      response = http.get(uri.request_uri)
      File.open(localpath, "w+") do |file|
        file.write response.body
      end
    end
  end

  def existing_cache_file
    begin
      File.open(localpath, "r")
    rescue
      nil
    end
  end

  def create_missing_folders
    FileUtils.makedirs File.dirname(localpath)
  end

  def localpath
    File.join ::Rails.root.to_s, "#{source_path}/#{source_filename}"
  end

  def remote_url
    "#{source_url}/#{source_filename}"
  end
end