Paperclip: Custom Download File

# Controller Action

  def custom_download
    id = params[:id]
    # model variable should have value like: Slide, DriveDocument, User, etc.
    model = params[:model]

    # file variable: should have paperclip object name like: attachment, image, etc.
    file = params[:file]
    if model.present? && id.present? && file.present?
      begin
        object = Object.const_get(model).find_by(id: id)
        data = object.send(file)
        data_content_type = object.send("#{file}_content_type")
      rescue => e
        Rollbar.error(e)
      end

      if object.present? && data_content_type.present? && data.present? && data.exists?
        if Rails.env.development?
          send_file data.path, filename: data.original_filename and return
        else
          data_read = open(data.expiring_url)
          send_data data_read.read, filename: data.original_filename, type: data_content_type, disposition: 'attachment' and return
        end
      else
        redirect_to root_path, alert: "We cannot find the file, please try again later." and return
      end
    else
      redirect_to root_path, alert: "Invalid parameters, please try again later." and return
    end
  end