Which is the better way to implement heartbeat on the client side for websockets?

On the Server side for websockets there is already an ping/pong implementation where the server sends a ping and client replies with a pong to let the server node whether a client is connected or not. But there isn't something implemented in reverse to let the client know if the server is still connected to them.

There are two ways to go about this I have read:

• 1. Every client sends a message to server every x seconds and whenever an error is thrown when sending, that means the server is down, so reconnect.
• 2. Server sends a message to every client every x seconds, the client receives this message and updates a variable on the client, and on the client side you have a thread that constantly checks every x seconds which checks if this variable has changed, if it hasn't in a while it means it hasn't received a message from the server and you can assume the server is down so reestablish a connection.

You can achieve trying to figure out on client side whether the server is still online using either methods. The first one you'll be sending traffic to the server whereas the second one you'll be sending traffic out of the server. Both seem easy enough to implement but I'm not so sure which is the better way in terms of being the more efficient/cost effective.

via DiderDrogba344