Is it possible to use websockets to send a request and get a response right after (without the publisher/subscriber structure)?

Question

I am using spring-websocket together with Kotlin Multiplatform, SockJS and StompJS.

I've got my application up and running, mainly using this tutorial from Spring. The frontend is able to send messages to the backend (via the @MessageMapping annotation), which responds back to frontend (via the @SendTo annotation).

The frontend code currently looks like this:

val socket = SockJS("http://localhost:8080/my-app")
val stompClient = Stomp.over(socket)
stompClient.connect(json(), { frame ->
    stompClient.subscribe("/topic/a-topic", { message ->
        // message handling code
    })
})

stompClient.send("/app/hello", null, "")

The subscription approach is useful when an action from some user needs to affect all users (like sending a message in a group chat). However, there are times when some actions should affect only the user who started the action, and that is my problem.

Ideally, I would like to do something to the likes of this:

val socket = SockJS("http://localhost:8080/my-app")
val stompClient = Stomp.over(socket)
stompClient.connect(json(), {})

stompClient.send("/app/hello", null, "").then { response ->
    // response handling code
}

But I don't know if it is possible.

I also thought about having a REST API handle this kind of request, but it doesn't seem optimal since there's the existing websocket connection already.

Any enlightment on the matter is appreciated.