What's the best way to send objects from a server ...

# ktor

[Sam Garfinkel]

What's the best way to send objects from a server via some interchange format (Json/Yaml/etc.) with websockets? Should I just serialize the object, then send the raw string/binary data via the associated Frame?

[Damian Lall]

I just serialize my objects into JSON with Klaxon and send it in a text frame. I find polymorphic serialization very useful in these cases as the receiver is easily able to determine what the objects are through the use of a type attribute in the JSON.

[Damian Lall]

This are the models I use for a simple messaging app (this code is shared between the app and server).

@TypeFor("type", TransmissionAdapter::class)
sealed class Transmission(val type: String)

class TransmissionAdapter: TypeAdapter<Transmission> {
    override fun classFor(type: Any): KClass<out Transmission> = when (type as String) {
        "user_join" -> UserJoin::class
        "user_leave" -> UserLeave::class
        "message" -> Message::class
        else -> throw IllegalArgumentException("Received unknown type $type")
    }
}

data class UserJoin(
    val name: String
) : Transmission("user_join")

data class UserLeave(
    val name: String
) : Transmission("user_leave")

data class Message(
    val channel: String,
    val text: String
) : Transmission("message")

[Sam Garfinkel]

Gotcha, yeah that's what I ended up doing tbh