# WebSocket state monitoring

**URL:** <https://softwaremill.community/t/websocket-state-monitoring/306>\
**Category:** sttp client\
**Created:** [November 1, 2023, 10:00am UTC](https://softwaremill.community/t/websocket-state-monitoring/306 "2023-11-01T10:00:09Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![ycomb](https://dub1.discourse-cdn.com/flex005/user_avatar/softwaremill.community/ycomb/32/199_2.png) [@ycomb](https://softwaremill.community/u/ycomb)\
**Post date:** [November 1, 2023, 10:00am UTC](https://softwaremill.community/t/websocket-state-monitoring/306/1 "2023-11-01T10:00:09Z")

</div>

Hi,

I’m trying to adopt `sttp4` client to interact with server via WebSockets. WebSockets seems unstable. For example, if a connection drops, `sttp4` throws exception:

```plaintext
Exception in thread "main" java.lang.ExceptionInInitializerError
	at WebSocketApp.main(WebSocket.scala)
Caused by: sttp.client4.SttpClientException$ReadException: Exception when sending request: GET wss://stream.server.com/public/
	at sttp.client4.SttpClientExceptionExtensions.defaultExceptionToSttpClientException(SttpClientExceptionExtensions.scala:24)
	at sttp.client4.SttpClientExceptionExtensions.defaultExceptionToSttpClientException$(SttpClientExceptionExtensions.scala:8)
	at sttp.client4.SttpClientException$.defaultExceptionToSttpClientException(SttpClientException.scala:24)
	at sttp.client4.httpclient.HttpClientBackend.adjustExceptions$$anonfun$1(HttpClientBackend.scala:55)
	at sttp.client4.SttpClientException$$anon$1.applyOrElse(SttpClientException.scala:35)
	at sttp.client4.SttpClientException$$anon$1.applyOrElse(SttpClientException.scala:34)
	at cats.ApplicativeError.recoverWith$$anonfun$1(ApplicativeError.scala:172)
	at modify @ fs2.internal.Scope.close(Scope.scala:262)
	at flatten @ sttp.client4.impl.cats.CatsMonadError.flatten(CatsMonadError.scala:21)
	at delay @ sttp.client4.impl.cats.CatsMonadError.eval(CatsMonadError.scala:19)
	at flatten @ sttp.client4.impl.cats.CatsMonadError.flatten(CatsMonadError.scala:21)
	at modify @ fs2.internal.Scope.close(Scope.scala:262)
	at flatten @ sttp.client4.impl.cats.CatsMonadError.flatten(CatsMonadError.scala:21)
Caused by: java.io.IOException: Software caused connection abort
	at java.base/sun.nio.ch.SocketDispatcher.read0(Native Method)
	at java.base/sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:47)
	at java.base/sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:330)
	at java.base/sun.nio.ch.IOUtil.read(IOUtil.java:284)
	at java.base/sun.nio.ch.IOUtil.read(IOUtil.java:259)
	at java.base/sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:417)
	at java.net.http/jdk.internal.net.http.SocketTube.readAvailable(SocketTube.java:1170)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription.read(SocketTube.java:833)
	at java.net.http/jdk.internal.net.http.SocketTube$SocketFlowTask.run(SocketTube.java:181)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:303)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:256)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription.signalReadable(SocketTube.java:774)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalReadPublisher$ReadEvent.signalEvent(SocketTube.java:957)
	at java.net.http/jdk.internal.net.http.SocketTube$SocketFlowEvent.handle(SocketTube.java:253)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.handleEvent(HttpClientImpl.java:979)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.lambda$run$3(HttpClientImpl.java:934)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.run(HttpClientImpl.java:934)
	at flatMap @ sttp.client4.impl.cats.CatsMonadError.flatMap(CatsMonadError.scala:12)
	at flatMap @ fs2.Compiler$Target.flatMap(Compiler.scala:163)
	at handleErrorWith @ fs2.Compiler$Target.handleErrorWith(Compiler.scala:161)
	at flatMap @ fs2.Compiler$Target.flatMap(Compiler.scala:163)

```

Sometimes `operation timed out` occurs:

```auto
Exception in thread "main" java.lang.ExceptionInInitializerError
	at WebSocketApp.main(WebSocket.scala)
Caused by: sttp.client4.SttpClientException$ReadException: Exception when sending request: GET wss://stream.bybit.com/v5/public/option
	at sttp.client4.SttpClientExceptionExtensions.defaultExceptionToSttpClientException(SttpClientExceptionExtensions.scala:24)
	at sttp.client4.SttpClientExceptionExtensions.defaultExceptionToSttpClientException$(SttpClientExceptionExtensions.scala:8)
	at sttp.client4.SttpClientException$.defaultExceptionToSttpClientException(SttpClientException.scala:24)
	at sttp.client4.httpclient.HttpClientBackend.adjustExceptions$$anonfun$1(HttpClientBackend.scala:55)
	at sttp.client4.SttpClientException$$anon$1.applyOrElse(SttpClientException.scala:35)
	at sttp.client4.SttpClientException$$anon$1.applyOrElse(SttpClientException.scala:34)
	at cats.ApplicativeError.recoverWith$$anonfun$1(ApplicativeError.scala:172)
	at modify @ fs2.internal.Scope.close(Scope.scala:262)
	at flatten @ sttp.client4.impl.cats.CatsMonadError.flatten(CatsMonadError.scala:21)
	at delay @ sttp.client4.impl.cats.CatsMonadError.eval(CatsMonadError.scala:19)
	at flatten @ sttp.client4.impl.cats.CatsMonadError.flatten(CatsMonadError.scala:21)
	at modify @ fs2.internal.Scope.close(Scope.scala:262)
	at flatten @ sttp.client4.impl.cats.CatsMonadError.flatten(CatsMonadError.scala:21)
Caused by: java.io.IOException: Operation timed out
	at java.base/sun.nio.ch.SocketDispatcher.read0(Native Method)
	at java.base/sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:47)
	at java.base/sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:330)
	at java.base/sun.nio.ch.IOUtil.read(IOUtil.java:284)
	at java.base/sun.nio.ch.IOUtil.read(IOUtil.java:259)
	at java.base/sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:417)
	at java.net.http/jdk.internal.net.http.SocketTube.readAvailable(SocketTube.java:1170)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription.read(SocketTube.java:833)
	at java.net.http/jdk.internal.net.http.SocketTube$SocketFlowTask.run(SocketTube.java:181)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:303)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:256)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription.signalReadable(SocketTube.java:774)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalReadPublisher$ReadEvent.signalEvent(SocketTube.java:957)
	at java.net.http/jdk.internal.net.http.SocketTube$SocketFlowEvent.handle(SocketTube.java:253)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.handleEvent(HttpClientImpl.java:979)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.lambda$run$3(HttpClientImpl.java:934)
	at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.run(HttpClientImpl.java:934)
	at flatMap @ sttp.client4.impl.cats.CatsMonadError.flatMap(CatsMonadError.scala:12)
	at flatMap @ fs2.Compiler$Target.flatMap(Compiler.scala:163)
	at handleErrorWith @ fs2.Compiler$Target.handleErrorWith(Compiler.scala:161)
	at flatMap @ fs2.Compiler$Target.flatMap(Compiler.scala:163)

```

I’m using the code from examples:

```plaintext
  implicit val runtime: IORuntime = cats.effect.unsafe.implicits.global

  private def webSocketFramePipe: Pipe[IO, WebSocketFrame.Data[_], WebSocketFrame] = { input =>
    Stream.emit(WebSocketFrame.text("""
                                      |{
                                      | "op": "subscribe",
                                      | "args": [
                                      | "topic-name"
                                      | ]
                                      |}
                                      |""".stripMargin)) ++ input.flatMap {
      case WebSocketFrame.Text(n, _, _) =>
        println(s"Received: $n")
        Stream.emit(WebSocketFrame.Ping(Array(2)))

      case x =>
        Stream.empty // ignoring
    }
  }

  HttpClientFs2Backend
    .resource[IO]()
    .use { backend =>
      basicRequest
        .get(uri"wss://stream.server.com/public")
        .response(asWebSocketStream(Fs2Streams[IO])(webSocketFramePipe))
        .send(backend)
        .void
    }
    .unsafeRunSync()

```

How to check the state of created WebSocket? And then reconnect it if it fails?

Also, I tried and found that if I send `Stream.empty` in `case WebSocketFrame.Text(n, _, _) =>` the data stream stops after ~30 frames. If I send `WebSocketFrame.Ping` then the server sends frames infinitely. What proper message should be sent in response to `case WebSocketFrame.Text`?