http4k Kotlin

import org.http4k.core.Method.GET
import org.http4k.core.MemoryBody
import org.http4k.core.Response
import org.http4k.core.Status.Companion.OK
import org.http4k.routing.bind
import org.http4k.routing.routes
import org.http4k.server.SunHttp
import org.http4k.server.asServer
import java.util.Base64

private val GIF = Base64.getDecoder().decode("R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==")

val app = routes(
    "/pixel.gif" bind GET to {
        Response(OK)
            .header("Content-Type", "image/gif")
            .header("Cache-Control", "no-store")
            .body(MemoryBody(GIF))
    },
)

fun main() {
    app.asServer(SunHttp(8080)).start()
}