One-shot rpc invocation option instead of a persisted ws session

[lsafer-meemer]

Is your feature request related to a problem? Please describe.
Websocket sessions could reach thousands when thousands of users have the client app open.
Yet, the only option to reduce that is to establish a ws connection in each invocation or establish
a ws connection that lives with the lifecycle of the app.

Don't get me wrong, I want long lived ws connection for communication between services but
not for communication between user client applications and a service.

Describe the solution you'd like
I don't exactly know if websocket sessions are very light or not for thousands of simultaneous long-lived
connections to be a problem but if so, there should be a way around that.

Maybe supporting different kinds of RemoteServices were one has instance-per-connection policy and
another is invocation-per-connection policy?

Describe alternatives you've considered
If kotlin-rpc was aimed to service-to-service communication, I think a gRPC kotlin wrapper would be a better choice.

On the other hand (if kotlin-rpc was aimed to client-to-service communication), I think the only alternative would
be Ktor resources (yuk!)

Additional context
I am creating a KMP project were the client app and the server app are both in Kotlin and I am searching for an
elegant more "natural" way of communication between the two.

[Mr3zee]

Hi, @lsafer-meemer! Thank you for the feature request. We are thinking about protocol enhancements, and we'll take this into consideration during the design

[PicoPocoo]

Or maybe keep the websocket connection open as long as one of the registered services are invoked. After an idle period of ( for example ) 5 seconds close the websocket and create a new websocket when there is another invocation of a registered service?

But to the be brutally honest, I have no idea how resource intensive it is to keep thousands of ( maybe mostly idle ) simultaneous websocket connections alive. Ktor is kinda great, so maybe they figured something smart out :)

[TheDome0]

I haven't found a way to detect when the underlying websocket session has closed. For example trying to add webSocketSession.outgoing.invokeOnClose {} throws an IllegalStateException saying that there already is another handler registered.