Need help completing the kotlinlang suggested exercise supporting Webhooks with javafx - kotlin

Question

In the tutorial, they teach how to support real-time p2p command-line messaging using websockets by implementing both client and server. I'm trying to finish an exercise where I have the client input messages via a javafx gui and receive messages inside the gui in the form of a chat log (basically a chat room)
I'm having trouble simply starting up the gui and the websocket together. I tried GlobalScope.launch in hopes that both would get run, but only the GUI gets launched. If I use runBlocking instead, only the websocket is active.
Here's what I have so far.
Other issues:
Don't know how to reference the javafx label variable inside the outputMessages function, so that we can update the chatlog. I try placing the label variable in the global scope, but it only results in a compile error, so I put it back inside SAKApplication.
How to update the label field to move to the next line (tried adding "/n" but it literally added "\n")
import java.util.Queue
import java.util.LinkedList
//var a = Label("s")
val messagesToSend: Queue<String> = LinkedList<String>()
class SAKApplication : Application() {
val l = Label("no text")
override fun start(primaryStage: Stage) {
val btn = Button()
btn.text = "Say 'Hello World'"
btn.onAction = EventHandler<ActionEvent> { println("Hello World!") }
val root = StackPane()
root.children.add(btn)
val textField = TextField()
// a = l
// action event
val event: EventHandler<ActionEvent> =
EventHandler {
l.text += "/n" + textField.getText()
messagesToSend.add(textField.getText())
}
// when enter is pressed
textField.setOnAction(event)
// add textfield
root.children.add(textField)
root.children.add(l)
val scene = Scene(root, 300.0, 250.0)
if (primaryStage != null) {
primaryStage.title = "Hello World!"
primaryStage.scene = scene
primaryStage.show()
}
val client = HttpClient {
install(WebSockets)
}
GlobalScope.launch {
client.webSocket(method = HttpMethod.Get, host = "127.0.0.1", port = 8080, path = "/chat") {
while(true) {
val messageOutputRoutine = launch { outputMessages() }
val userInputRoutine = launch { inputMessages() }
userInputRoutine.join() // Wait for completion; either "exit" or error
messageOutputRoutine.cancelAndJoin()
}
}
}
client.close()
}
}
fun main(args: Array<String>) {
Application.launch(SAKApplication::class.java, *args)
}
suspend fun DefaultClientWebSocketSession.outputMessages() {
try {
for (message in incoming) {
message as? Frame.Text ?: continue
// a.text += "/n" + message.readText()
println(message.readText())
}
} catch (e: Exception) {
println("Error while receiving: " + e.localizedMessage)
}
}
suspend fun DefaultClientWebSocketSession.inputMessages() {
val name = readLine() ?: ""
send(name)
while (true) {
sleep(1)
if (messagesToSend.isEmpty()) { continue }
val message = messagesToSend.remove()
if (message.equals("exit", true)) return
try {
send(message)
} catch (e: Exception) {
println("Error while sending: " + e.localizedMessage)
return
}
}
}