Hey folks. I'm new to Kotlin and coroutines. I hav...

# coroutines

[Gus]

Hey folks. I'm new to Kotlin and coroutines. I have a function that will return a Flow<Thingy> and, in some cases, that flow/job should be cancelled if no new Thingy has been emitted in the past X seconds (and I'll need to close an underlying connection when the flow is cancelled). Is there any readily-available utility to achieve this? If not, does anyone have any pointers on how to do this in an idiomatic way?

If I have to implement it myself, I'm thinking of implementing it as two separate functions: getThingy(): Flow<Thingy> and getThingy(timeoutMillis: Int): Flow<Thingy>. getThingy() would return a cancellable flow, and getThingy(timeoutMillis) would use the former function behind the scenes and add the timeout logic. I'm thinking of using Timer.schedule() in the timeout logic so I can cancel the timer and start a new one each time a new Thingy is emitted, but I wonder whether there's a better way to do this.

[pedro]

I’m not particularly proud, but this does what you want:

fun main() {
    val flow = flow {
        emit(1)
        delay(250)
        emit(2)
        delay(250)
        emit(3)
        delay(250)
        emit(4)
        delay(1250)
        emit(5)
    }

    runBlocking {
        launch {
            flow.transformLatest {
                emit(it)
                delay(1000)
                cancel("Timeout")
            }.collect{
                println(it)
            }
        }
    }
}

[Gus]

Thanks Pedro!