fix(websockets): Discard torn close reasons

Author: willmmiles

src/AsyncWebSocket.cpp

@@ -698,11 +698,12 @@ bool AsyncWebSocketClient::_handleClientFrame(uint8_t *data, size_t datalen, boo
     if (_pinfo.opcode == WS_DISCONNECT) {
       async_ws_log_v("[%s][%" PRIu32 "] DATA WS_DISCONNECT", _server->url(), _clientId);
 
-      if (datalen) {
+      // Pass up the close frame error code if we can.  If the frame was torn, the data was discarded.
+      if ((_pinfo.index == 0) && (datalen >= 2)) {
         uint16_t reasonCode = (uint16_t)(data[0] << 8) + data[1];
         char *reasonString = (char *)(data + 2);
         if (reasonCode > 1001) {
-          _server->_handleEvent(this, WS_EVT_ERROR, (void *)&reasonCode, (uint8_t *)reasonString, strlen(reasonString));
+          _server->_handleEvent(this, WS_EVT_ERROR, (void *)&reasonCode, (uint8_t *)reasonString, strnlen(reasonString, datalen - 2));
         }
       }
       if (_status == WS_DISCONNECTING) {