code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.remote.http.netty;
  
  import java.net.MalformedURLException;
  import java.net.URI;
  import java.net.URISyntaxException;
  import java.net.URL;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.atomic.AtomicReference;
  import java.util.function.BiFunction;
  import java.util.function.Function;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  import org.asynchttpclient.AsyncHttpClient;
  import org.asynchttpclient.ListenableFuture;
  import org.asynchttpclient.Request;
  import org.asynchttpclient.ws.WebSocketListener;
  import org.asynchttpclient.ws.WebSocketUpgradeHandler;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.remote.http.BinaryMessage;
  import org.openqa.selenium.remote.http.ClientConfig;
  import org.openqa.selenium.remote.http.CloseMessage;
  import org.openqa.selenium.remote.http.ConnectionFailedException;
  import org.openqa.selenium.remote.http.Filter;
  import org.openqa.selenium.remote.http.HttpRequest;
  import org.openqa.selenium.remote.http.HttpResponse;
  import org.openqa.selenium.remote.http.Message;
  import org.openqa.selenium.remote.http.TextMessage;
  import org.openqa.selenium.remote.http.WebSocket;
  
  class NettyWebSocket implements WebSocket {
  
    private static final Logger LOG = Logger.getLogger(NettyWebSocket.class.getName());
  
    private final org.asynchttpclient.ws.WebSocket socket;
  
    private NettyWebSocket(AsyncHttpClient client, Request request, Listener listener) {
      Require.nonNull("HTTP client", client);
      Require.nonNull("WebSocket listener", listener);
  
      try {
        URL origUrl = new URL(request.getUrl());
        String wsScheme = "https".equalsIgnoreCase(origUrl.getProtocol()) ? "wss" : "ws";
  
        URI wsUri =
            new URI(
                wsScheme, null, origUrl.getHost(), origUrl.getPort(), origUrl.getPath(), null, null);
        ListenableFuture<org.asynchttpclient.netty.ws.NettyWebSocket> future =
            client
                .prepareGet(wsUri.toString())
                .execute(
                    new WebSocketUpgradeHandler.Builder()
                        .addWebSocketListener(
                            new WebSocketListener() {
                              @Override
                              public void onOpen(org.asynchttpclient.ws.WebSocket websocket) {}
  
                              @Override
                              public void onClose(
                                  org.asynchttpclient.ws.WebSocket websocket,
                                  int code,
                                  String reason) {
                                listener.onClose(code, reason);
                              }
  
                              @Override
                              public void onError(Throwable t) {
                                listener.onError(t);
                              }
  
                              @Override
                              public void onBinaryFrame(
                                  byte[] payload, boolean finalFragment, int rsv) {
                                if (payload != null) {
                                  listener.onBinary(payload);
                                }
                              }
  
                              @Override
                              public void onTextFrame(
                                  String payload, boolean finalFragment, int rsv) {
                                if (payload != null) {
                                  listener.onText(payload);
                                }
                              }
                            })
                        .build());
        socket =
            future
                .toCompletableFuture()
                .exceptionally(
                    t -> {
                      LOG.log(Level.WARNING, t.getMessage(), t);
                      return null;
                    })
                .get();
  
        if (socket == null) {
          throw new ConnectionFailedException(
              "Unable to establish websocket connection to " + request.getUrl());
        }
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
        LOG.log(Level.WARNING, "NettyWebSocket initial request interrupted", e);
        throw new ConnectionFailedException("NettyWebSocket initial request interrupted", e);
      } catch (ExecutionException | MalformedURLException | URISyntaxException e) {
        throw new ConnectionFailedException("NettyWebSocket initial request execution error", e);
      }
    }
  
    static BiFunction<HttpRequest, Listener, WebSocket> create(
        ClientConfig config, AsyncHttpClient client) {
      Filter filter = config.filter();
  
      Function<HttpRequest, HttpRequest> filterRequest =
          req -> {
            AtomicReference<HttpRequest> ref = new AtomicReference<>();
            filter
                .andFinally(
                    in -> {
                      ref.set(in);
                      return new HttpResponse();
                    })
                .execute(req);
            return ref.get();
          };
  
      return (req, listener) -> {
        HttpRequest filtered = filterRequest.apply(req);
        Request nettyReq = NettyMessages.toNettyRequest(config, filtered);
        return new NettyWebSocket(client, nettyReq, listener);
      };
    }
  
    @Override
    public WebSocket send(Message message) {
      if (message instanceof BinaryMessage) {
        socket.sendBinaryFrame(((BinaryMessage) message).data());
      } else if (message instanceof CloseMessage) {
        socket.sendCloseFrame(((CloseMessage) message).code(), ((CloseMessage) message).reason());
      } else if (message instanceof TextMessage) {
        socket.sendTextFrame(((TextMessage) message).text());
      }
  
      return this;
    }
  
    @Override
    public WebSocket sendText(CharSequence data) {
      socket.sendTextFrame(data.toString());
      return this;
    }
  
    @Override
    public void close() {
      socket.sendCloseFrame(1000, "WebDriver closing socket");
    }
  }
  