Ktor Map Session.kt

fun PipelineContext<*, ApplicationCall>.setSession(id: String, value: String) {
    val session = call.sessions.get<Session>() ?: Session()
    session.data[id] = value
    call.sessions.set(session)
}

fun PipelineContext<*, ApplicationCall>.getSession(id: String): String? {
    return call.sessions.get<Session>()?.data?.get(id)
}

fun PipelineContext<*, ApplicationCall>.clearSession(id: String): String? {
    return call.sessions.get<Session>()?.data?.remove(id)
}

class Session(val data: HashMap<String, String> = hashMapOf())