title: How to Download xls file stored in Ir_attachment or open an xls file saved in local?
body: <p>I use odoo8 with old api for the moment.
  I have created an xls file and stored it in ir_attachment.
  Now i need to download it so the client user can choose to download it in a selected local location or ope the xls file using microsoft excel or any app which can open xls file.
  I can see Odoo is using saveas and saveas_ajax, but i'm not able to make that work (not much details on passing data to those methods).
  So the question is:</p>
  
  <ul>
  <li>List item
  how to download the xls file in a location that needs to be chosen by the web user?</li>
  </ul>
  
  <p>or how to write the xls file locally to client side in a location that is chosen by the client user?</p>
  
  <p>Many thanks in advance!</p>