Kotlin Programming: The Big Nerd Ranch Guide, 2nd Edition

Receiving from a Channel

With your producer in place, you can create your first worker. Add a function to define the worker’s behavior, then launch it in its own coroutine.

Listing 22.2  Receiving from a channel (FlightWatcher.kt)

...
suspend fun fetchFlights(
    passengerNames: List<String> = listOf("Madrigal", "Polarcubis")
): List<FlightStatus> = coroutineScope {
    val passengerNamesChannel = Channel<String>()

    launch {
        passengerNames.forEach {
            passengerNamesChannel.send(it)
        }
    }

    launch {
        fetchFlightStatuses(passengerNamesChannel)
    }

    emptyList()
}

suspend fun fetchFlightStatuses(
    fetchChannel: Channel<String>
) {
    val passengerName = fetchChannel.receive()
    val flight = fetchFlight(passengerName)
    println("Fetched flight: $flight")
}