paperclip_migrations.rb

module PaperclipMigrations

  def self.included(base)
    base.extend ClassMethods
  end

  module ClassMethods
    def add_paperclip_fields(table, prefix)
      add_column table, "#{prefix}_file_name", :string
      add_column table, "#{prefix}_content_type", :string
      add_column table, "#{prefix}_file_size", :integer
      add_column table, "#{prefix}_updated_at", :datetime
    end

    def remove_paperclip_fields(table, prefix)
      remove_column table, "#{prefix}_file_name"
      remove_column table, "#{prefix}_content_type"
      remove_column table, "#{prefix}_file_size"
      remove_column table, "#{prefix}_updated_at"
    end

    def populate_paperclip_from_attachment_fu(model, attachment, prefix, path_prefix)
      unless attachment.filename.nil?
        model.send("#{prefix}_file_name=", attachment.filename)
        model.send("#{prefix}_content_type=", attachment.content_type)
        model.send("#{prefix}_file_size=", attachment.size)

        file_path = ("%08d" % model.id).scan(/..../).join('/')
        old_path = File.join(RAILS_ROOT, 'public', path_prefix, file_path, attachment.filename)
        new_path = model.send(prefix).path(:original)

        if File.exists?(old_path)
          puts "Moving #{old_path} to Paperclip"
          file = File.open(old_path)
          model.send("#{prefix}=",file)
          model.save
          file.close
        else
          puts "No such file: #{old_path}"
        end
      end
    end
  end

end