Play 3.0.x / Pekko support

[PromanSEW]

Seems like maintainers abandoned this project and never release any working version.
So I created "fork" and adapted imports for Play 3.0.x / Pekko:
https://github.com/PromanSEW/play-socket.io-3.x

Creating PR for this project is pretty complicated as of 2.9.x / 3.0.x branches needed

[PromanSEW]

Unfortunately, I cannot force to work this implementation with modern socket.io for Java (2.1.2)
Only web socket.io 2.0.3 included in original Play repo is working
With Java client I get parser error while connecting:

Socket mSocket = IO.socket("http://localhost:9000/chat", IO.Options.builder().setQuery("user=PromanSEW").build());
mSocket.on(Socket.EVENT_CONNECT_ERROR, arg -> System.out.println(((EngineIOException) arg[0]).code)); // parser error
mSocket.connect();
mSocket.emit("join room", new JSONObject().put("room", "kek").put("user", "PromanSEW"));
mSocket.emit("chat message", new JSONObject().put("room", "kek").put("user", "PromanSEW").put("message", "Test"));
mSocket.emit("leave room", new JSONObject().put("room", "kek").put("user", "PromanSEW"));
mSocket.on("chat message", args1 -> {
    JSONObject data = (JSONObject) args1[0];
    try {
      System.out.println(data.getString("user"));
      System.out.println(data.getString("message"));
  } catch (JSONException e) {
      e.printStackTrace();
  }
});

On the server side it prints username in socketIO.createBuilder().onConnect() (line 51), but never in createFlow (line 60)

play-socket.io/samples/java/multi-room-chat/app/chat/ChatEngine.java

Lines 51 to 60 in b29f4e0

	val username = request.getQueryString("user");
	if (username == null) {
	throw new RuntimeException("No user parameter");
	}
	// And return the user, this will be the data for the session that we can read when we add a namespace
	return new User(username);
	}).addNamespace(codec, (session, chat) -> {
	if (chat.split("\\?")[0].equals("/chat")) {
	return Optional.of(createFlow(session.data()));

[PromanSEW]

After debugging I found where is error is thrown (in line 56).
https://github.com/socketio/engine.io-client-java/blob/050dd2653a6c510e91679897c39ad849ee5f0132/src/main/java/io/socket/engineio/parser/Parser.java#L53-L66
data is very strange here? first bytes are not printable, so there is error

If I delete all symbols before 0, then client connects, but server throws EngineIOEncodingException: Malformed packet:

! @8a11eh2lf - Internal server error, for (GET) [/socket.io/?EIO=4&transport=polling&user=PromanSEW&sid=8184c6ae-61c7-4929-bb47-7c6133ffc05b] ->

play.api.PlayException: Execution exception[[UnknownSessionId: Unknown session id: 8184c6ae-61c7-4929-bb47-7c6133ffc05b]]
        at play.api.http.HttpErrorHandlerExceptions$.$anonfun$convertToPlayException$3(HttpErrorHandler.scala:407)
        at scala.Option.getOrElse(Option.scala:201)
        at play.api.http.HttpErrorHandlerExceptions$.convertToPlayException(HttpErrorHandler.scala:407)
        at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:390)
        at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:267)
        at play.core.server.PekkoHttpServer$$anonfun$invokeAction$1$1.applyOrElse(PekkoHttpServer.scala:482)
        at play.core.server.PekkoHttpServer$$anonfun$invokeAction$1$1.applyOrElse(PekkoHttpServer.scala:474)
        at scala.concurrent.impl.Promise$Transformation.run(Promise.scala:490)
        at org.apache.pekko.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:73)
        at org.apache.pekko.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:110)
Caused by: play.engineio.UnknownSessionId: Unknown session id: 8184c6ae-61c7-4929-bb47-7c6133ffc05b
WARN  p.e.EngineIOController - Error on outgoing WebSocket
play.engineio.UnknownSessionId: Unknown session id: 8184c6ae-61c7-4929-bb47-7c6133ffc05b
WARN  p.e.EngineIOController - Error on incoming WebSocket
play.engineio.UnknownSessionId: Unknown session id: 8184c6ae-61c7-4929-bb47-7c6133ffc05b
ERROR p.a.h.DefaultHttpErrorHandler -

! @8a11eh2ni - Internal server error, for (POST) [/socket.io/?EIO=4&transport=polling&user=PromanSEW&sid=8184c6ae-61c7-4929-bb47-7c6133ffc05b] ->

play.api.PlayException: Execution exception[[EngineIOEncodingException: Malformed packet]]

[ihostage]

Creating PR for this project is pretty complicated as of 2.9.x / 3.0.x branches needed

Hi, @PromanSEW! 👋
It isn't a problem. You can think that main branch is Play 3/Pekko compatible and you can create PR to step by step improve this module.
Everyone will be happy if we'll finish and release a stable version of Play Socket.IO module 😉

[PromanSEW]

@ihostage okay, but I would have to fix the problem above at first... I am not sure I can, because I don't know Pekko at all, just blindly debugging both client and server libraries is not very productive to understand where it is broken.
Thanks I likely fixed web example, so there is working realization available with very old 2.0.3 web client at least

[PromanSEW]

There are good and bad news.
Good news: current implementation works with Java socket.io-client:1.0.2
Bad news: it does not work with the last 2.1.2 version. probably because of different server protocol.
What should I do? I can't update current codebase to support new version anyway

[PromanSEW]

I think we can update current codebase for last Play and release so it will be at least some support of socket.io, even if it is an old version, right? It is better than nothing, anyway