title: GAE Channels to multiple clients?
body: <p>I'm trying to wrap my head around the <code>channel</code> features of Google App Engine since they don't (easily) provide websockets.</p>
  
  <p>My current situation is that I have a long work (file processing) that is being executed asynchronously via a worker.
  This worker update the state of the file processing in the database at every lines in order to inform the customer.</p>
  
  <p>From that current perspective, a F5 will indicate the evolution of the processing.</p>
  
  <p>Now I'd like to implement a live update system. Of course I could do an XHR request every 5 seconds but a live connection seems better... introducing Channels since Websockets seems out of the possibilities.</p>
  
  <p>From what I understood, I can <code>channel.send_message</code> to one client only, not to a "room". The issue here, is that the worker that process the file does not have any information which customer is currently connected (could be one, could be ten).</p>
  
  <p>I could loop over all the customer and post to each client_id, suspecting that at least one of them will get the message, but this is awfully useless and too resourceful.</p>
  
  <p>I was hoping there was a better way to achieve this ? Maybe a nice alternative to Google <code>Channels</code> feature without having to reconfigure my whole App Engine system (like for Websockets)?</p>