Will spec add HEARTBEAT message?

[SunFulong]

As I know, browser's websocket client can't send websocket native ping/pong message, so if a websocket have a short idle timeout (10 mins), connection will drop frequently, will spec add HEARTBEAT message to keep alive the connection?

[konsultaner]

@SunFulong WebSockets have HEARTBEATs and so do RawSockets. Just look for ping and pong

[SunFulong]

@SunFulong WebSockets have HEARTBEATs and so do RawSockets. Just look for ping and pong

I know ping/pong, but web browser can't send out ping message

[KSDaemon]

You're right. There is no way around that.
For now you have a few options:

1. Setup ping messages on the router side as some implementations allow that.
2. Setup fake RPC in your backend and call it regularly from the browser client side or even just publish to some meaningless topic with confirmation (thus you can be sure that both directions work: r/w)

IDK about introducing ping/pong into the WAMP protocol itself... As WAMP — is an Application level protocol. And it is not caring much about transport problems (to some degree). And btw, the problem is only with one specific transport and only in one type of environment: browser.

[oberstet]

Yes, to the best of my knowledge:

• there is no W3C API defined to control WebSocket ping/pong control frames from JavaScript or other W3C API users
• there is no way to configure Google Chrome / Mozilla Firefox so that it automatically sends WebSocket ping control frames on WebSocket connections opened from JavaScript
• all browsers support responding to received WebSocket pings though

That means, heartbeating on WebSocket needs to be done manually, at the application level, using regular WebSocket data frames.

For realiable heartbeating, those need to be initiated from two sides .. from the router and from the client.

As @KSDaemon notes, some WAMP routers allow automatic router initiated WebSocket ping control frames.

For the other direction (client initiated): you need app level, as described above.

E.g. do acknowledged WAMP publications, or perform some WAMP RPC regularily ..

Since you can use any acknowledged publication (the "pong" is the WAMP ACK for the publication), I don't see much pressure to standardize that in WAMP currently ...

[SunFulong]

Setup ping messages on the router side as some implementations allow that.

@KSDaemon , I will going to setup PING and PONG message with message code 256 and 257, implement it like ICMP.

[SunFulong]

E.g. do acknowledged WAMP publications, or perform some WAMP RPC regularily

@oberstet , Why not make a real PING/PONG message, exchange some runtime datas, such as each side timestamp.

[KSDaemon]

First of all, it will be backward incompatible %) So any brand new client sending a PING message will end with its connection being aborted.

[oberstet]

https://github.com/wamp-proto/wamp-proto/blob/master/rfc/text/basic/bp_03_messages.md#extension-messages allows

Implementations MAY define and use implementation specific messages with message type codes from the extension message range [256, 1023].

what the current spec text might lack to mention explicitly for extension messages:

• how this is announced by a peer
• how a peer not supporting the announced use of extension messages should do
• what a peer not understanding extension messages used should do (even though it did not deny to connect having seen the announcement)

[om26er]

One workaround that I use to "emulate" a ping on top of WAMP is to publish to a topic like foo.bar.echo with acknowledge set to true. That essentially means the communication between the router and the client is intact and functional.

[SunFulong]

I'm a little shaky, maybe using a dummy topic is a better approach.