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.devtools;
  
  import static java.util.concurrent.TimeUnit.MILLISECONDS;
  
  import java.io.Closeable;
  import java.time.Duration;
  import java.util.List;
  import java.util.Optional;
  import java.util.concurrent.CompletableFuture;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.TimeoutException;
  import java.util.function.Consumer;
  import java.util.function.Function;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  import org.openqa.selenium.WebDriver;
  import org.openqa.selenium.devtools.idealized.Domains;
  import org.openqa.selenium.devtools.idealized.target.model.SessionID;
  import org.openqa.selenium.devtools.idealized.target.model.TargetID;
  import org.openqa.selenium.devtools.idealized.target.model.TargetInfo;
  import org.openqa.selenium.internal.Require;
  
  public class DevTools implements Closeable {
    private static final Logger LOG = Logger.getLogger(DevTools.class.getName());
  
    private final Domains protocol;
    private final Duration timeout = Duration.ofSeconds(10);
    private final Connection connection;
    private SessionID cdpSession = null;
  
    public DevTools(Function<DevTools, Domains> protocol, Connection connection) {
      this.connection = Require.nonNull("WebSocket connection", connection);
      this.protocol = Require.nonNull("CDP protocol", protocol).apply(this);
    }
  
    public Domains getDomains() {
      return protocol;
    }
  
    @Override
    public void close() {
      disconnectSession();
      connection.close();
    }
  
    public void disconnectSession() {
      if (cdpSession != null) {
        SessionID id = cdpSession;
        cdpSession = null;
        try {
          connection.sendAndWait(
              cdpSession,
              getDomains().target().detachFromTarget(Optional.of(id), Optional.empty()),
              timeout);
        } catch (Exception e) {
          // Exceptions should not prevent closing the connection and the web driver
          LOG.warning("Exception while detaching from target: " + e.getMessage());
        }
      }
    }
  
    public <X> X send(Command<X> command) {
      Require.nonNull("Command to send", command);
      return connection.sendAndWait(cdpSession, command, timeout);
    }
  
    public <X> void addListener(Event<X> event, Consumer<X> handler) {
      Require.nonNull("Event to listen for", event);
      Require.nonNull("Handler to call", handler);
  
      connection.addListener(event, handler);
    }
  
    public void clearListeners() {
      // By removing all the listeners, we should also disable all the domains
      getDomains().disableAll();
  
      connection.clearListeners();
    }
  
    public void createSessionIfThereIsNotOne() {
      createSessionIfThereIsNotOne(null);
    }
  
    public void createSessionIfThereIsNotOne(String windowHandle) {
      if (cdpSession == null) {
        createSession(windowHandle);
      }
    }
  
    public void createSession() {
      createSession(null);
    }
  
    /**
     * Create CDP session on given window/tab (aka target). If windowHandle is null, then the first
     * "page" type will be selected. Pass the windowHandle if you have multiple windows/tabs opened to
     * connect to the expected window/tab.
     *
     * @param windowHandle result of {@link WebDriver#getWindowHandle()}, optional.
     */
    public void createSession(String windowHandle) {
      if (connection.isClosed()) {
        connection.reopen();
      }
      TargetID targetId = findTarget(windowHandle);
  
      // Starts the session
      // CDP creates a parent browser session when websocket connection is made
      // Create session that is child of parent browser session and not child of already existing
      // child page session
      // Passing null for session id helps achieve that
      // Child of already existing child page session throws an error when detaching from the target
      // CDP allows attaching to child of child session but not detaching. Maybe it does not keep
      // track of it.
      cdpSession =
          connection.sendAndWait(null, getDomains().target().attachToTarget(targetId), timeout);
  
      try {
        // We can do all of these in parallel, and we don't care about the result.
        CompletableFuture.allOf(
                // Set auto-attach to true and run for the hills.
                connection.send(cdpSession, getDomains().target().setAutoAttach()),
                // Clear the existing logs
                connection
                    .send(cdpSession, getDomains().log().clear())
                    .exceptionally(
                        t -> {
                          LOG.log(Level.SEVERE, t.getMessage(), t);
                          return null;
                        }))
            .get(timeout.toMillis(), MILLISECONDS);
      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
        throw new IllegalStateException("Thread has been interrupted", e);
      } catch (ExecutionException e) {
        throw new DevToolsException(unwrapCause(e));
      } catch (TimeoutException e) {
        throw new org.openqa.selenium.TimeoutException(e);
      }
    }
  
    private TargetID findTarget(String windowHandle) {
      // Figure out the targets.
      List<TargetInfo> infos =
          connection.sendAndWait(cdpSession, getDomains().target().getTargets(), timeout);
  
      // Grab the first "page" type, and glom on to that.
      // Find out which one might be the current one
      // (using given window handle like "CDwindow-24426957AC62D8BC83E58C184C38AF2D")
      return infos.stream()
          .filter(info -> "page".equals(info.getType()))
          .map(TargetInfo::getTargetId)
          .filter(id -> windowHandle == null || windowHandle.contains(id.toString()))
          .findAny()
          .orElseThrow(() -> new DevToolsException("Unable to find target id of a page"));
    }
  
    private Throwable unwrapCause(ExecutionException e) {
      return e.getCause() != null ? e.getCause() : e;
    }
  
    public SessionID getCdpSession() {
      return cdpSession;
    }
  }
  