Ping

{
  "id": "1545910590801",
  "type": "ping"
}

To prevent the TCP link being disconnected by the server, the client side needs to send ping messages every pingInterval time to the server to keep alive the link.

After the ping message is sent to the server, the system would return a pong message to the client side.

If the server has not received any message from the client for a long time, the connection will be disconnected.

{
  "id": "1545910590801",
  "type": "pong"
}