Heartbeat messages to prevent timeouts about braid-spec HOT 8 CLOSED

I have two different proposals for this:

1. In between updates in a subscription, the client will ignore any arbitrary number of newline (\n) characters. These newlines may be inserted periodically by the server to keep a connection alive.
2. Allow "empty" update messages. Eg Heart: beat\n\n between real updates

My preference is (1), though I'm happy to be convinced if anyone has another idea. Otherwise I'll write up a PR.

from braid-spec.

Both options seem reasonable. I also prefer (1).

from braid-spec.

Me too. I've made this change to braid-protocol to send \n newlines as heartbeat messages, and the client ignores any newlines between updates.

from braid-spec.

Shouldn't heartbeats be done at a transport level and not at braid level? E.g., if subscriptions are done using SSE, then you can use some hearbeat event type. If you use Websockets, then you can use built-in heartbeats.

from braid-spec.

Shouldn't heartbeats be done at a transport level and not at braid level?

To clarify, Braid defines protocols over different transports (e.g. HTTP and WebSocket), and yes, the encoding of a heartbeat will be different on each one. In this issue we've been discussing how to encode heartbeats in the Braid-HTTP version.

If you use Websockets, then you can use built-in heartbeats.

Good call! I hadn't realized it until you brought it up, but WebSockets do have a built-in ping/pong frame type: https://stackoverflow.com/a/46112000

This isn't exposed in the Javascript APIs for web browsers, but clients will respond to a ping with a pong if the server initiates the ping.

from braid-spec.

WebSockets built-in ping might be a problem if we care that the JavaScript client knows if the connection is still up or not.

from braid-spec.

The connection should get closed automatically by the browser when the server goes down or there’s a timeout. I guess we could speed up that timeout if we send our own ping messages. We could add a no-op update message I suppose. I’m not sure how much this matters in practice.

from braid-spec.

This has been implemented in 9651ad0. Closing.

from braid-spec.