title: CORS-enable autobahn.asyncio.websocket server
body: <p>I create a local Python 3 server using autobahn.asyncio.websocket that talks to a JavaScript client in a local browser. In the client I want to fetch from the server jpegs to use as textures and font files to enable extruding 3D text. The browser window shows an address "file:///.....html", having been created in the Python server with webbrowser.open("file:///.....html"). I need to CORS-enable the server, and it looks like the way to do that is as follows:</p>
  
  <p>factory = WebSocketServerFactory(u"ws://localhost:9000/")
  factory.setProtocolOptions(allowedOrigins=['*'])</p>
  
  <p>But I get an error "origin 'file://' not allowed".</p>
  
  <p>How can I permit the client to read data files from the server?</p>