In websocket_server.PyWebSocket.start() method, it open file by codecs.open(output_log, "utf-8"), but second parameter should be "r" here. Also, it would be nice to kill the websocket server process when the process is running, but url is not alive.
Created attachment 57739 [details] Patch
Committed r60654: <http://trac.webkit.org/changeset/60654>