--- a/net/websocket.lua	Thu Nov 05 22:27:17 2020 +0100
+++ b/net/websocket.lua	Thu Nov 05 22:31:25 2020 +0100
@@ -23,6 +23,7 @@
 local websocket_listeners = {};
 function websocket_listeners.ondisconnect(conn, err)
 	local s = websockets[conn];
+	if not s then return; end
 	websockets[conn] = nil;
 	if s.close_timer then
 		timer.stop(s.close_timer);
@@ -113,7 +114,7 @@
 				frame.MASK = true; -- RFC 6455 6.1.5: If the data is being sent by the client, the frame(s) MUST be masked
 				conn:write(frames.build(frame));
 			elseif frame.opcode == 0xA then -- Pong frame
-				log("debug", "Received unexpected pong frame: " .. tostring(frame.data));
+				log("debug", "Received unexpected pong frame: %s", frame.data);
 			else
 				return fail(s, 1002, "Reserved opcode");
 			end
@@ -131,7 +132,7 @@
 function websocket_methods:close(code, reason)
 	if self.readyState < 2 then
 		code = code or 1000;
-		log("debug", "closing WebSocket with code %i: %s" , code , tostring(reason));
+		log("debug", "closing WebSocket with code %i: %s" , code , reason);
 		self.readyState = 2;
 		local conn = self.conn;
 		conn:write(frames.build_close(code, reason, true));
@@ -245,7 +246,7 @@
 		   or (protocol and not protocol[r.headers["sec-websocket-protocol"]])
 		   then
 			s.readyState = 3;
-			log("warn", "WebSocket connection to %s failed: %s", url, tostring(b));
+			log("warn", "WebSocket connection to %s failed: %s", url, b);
 			if s.onerror then s:onerror("connecting-failed"); end
 			return;
 		end