Secure websockets with Lagom

Question

With the lightbend Lagom framework I'm trying to connect to the websocket api of Binance.

However, I'm keep getting the following error on connecting:

400 The plain HTTP request was sent to HTTPS port

Should it be possible from Lagom to connect to a secure websocket service? So with WebSocketClient? I have the following code:

trait BinanceStreamingService extends Service {
    def depthStream(symbol: String): ServiceCall[NotUsed, Source[DepthEvent, NotUsed]]

    override final def descriptor = {
        import Service._
        import me.koopal.crypto.api.BinanceModelsMarshallers._

        named("depth-stream")
            .withCalls(
                restCall(GET, "/ws/:symbol@deth", depthStream _)
            )
     }
} 

private val binanceStreamApplication = new LagomClientApplication("binance-ws") with StaticServiceLocatorComponents with AhcWSComponents {
    override def staticServiceUri = URI.create("wss://stream.binance.com:9443")
}

override def stream = ServiceCall { _ =>
    binanceStreamClient.depthStream("bnbbtc")
        .invoke()
        .map { s =>
            s.runForeach(e => println(e))
        }.onComplete {
            case Success(x) => println("success", x)
            case Failure(ex) => println("failure", ex)
        }

        Future.successful("test")
}

A ruuning code example can be found here: https://github.com/stijnkoopal/lagom-binance-websockets

Answer 1

Lagom's WebSocket client does not yet support TLS. There is an open issue to reimplement the client using Akka HTTP, which will enable TLS support: https://github.com/lagom/lagom/issues/895

In the meantime, the best approach is to implement your client using Akka HTTP Client-Side WebSocket Support or another WebSocket client library that supports secure connections.