title: how to create a downloadable csv file in appengine
body: <p>I use python Appengine. I'm trying to create a link on a webpage, which a user can click to download a csv file. How can I do this?</p>
  
  <p>I've looked at csv module, but it seems to want to open a file on the server, but appengine doesn't allow that. </p>
  
  <p>I've looked at remote_api, but it seems that its only for uploading or downloading using app config, and from account owner's terminal.</p>
  
  <p>Any help thanks.</p>