This is the multi-page printable view of this section. Click here to print.

Return to the regular view of this page.

Chrome DevTools Protocol

Examples of working with Chrome DevTools Protocol in Selenium. CDP support is temporary until WebDriver BiDi has been implemented.

1: Chrome DevTools Logging Features
2: Chrome DevTools Network Features
3: Chrome DevTools Script Features

Many browsers provide “DevTools” – a set of tools that are integrated with the browser that developers can use to debug web apps and explore the performance of their pages. Google Chrome’s DevTools make use of a protocol called the Chrome DevTools Protocol (or “CDP” for short). As the name suggests, this is not designed for testing, nor to have a stable API, so functionality is highly dependent on the version of the browser.

Selenium is working to implement a standards-based, cross-browser, stable alternative to CDP called [WebDriver BiDi]. Until the support for this new protocol has finished, Selenium plans to provide access to CDP features where applicable.

Using Chrome DevTools Protocol with Selenium

Chrome and Edge have a method to send basic CDP commands. This does not work for features that require bidirectional communication, and you need to know what domains to enable when and the exact names and types of domains/methods/parameters.

    Map<String, Object> cookie = new HashMap<>();
    cookie.put("name", "cheese");
    cookie.put("value", "gouda");
    cookie.put("domain", "www.selenium.dev");
    cookie.put("secure", true);
    ((HasCdp) driver).executeCdpCommand("Network.setCookie", cookie);

View full example on GitHub

    cookie = {'name': 'cheese',
              'value': 'gouda',
              'domain': 'www.selenium.dev',
              'secure': True}

    driver.execute_cdp_cmd('Network.setCookie', cookie)

View full example on GitHub

            var cookie = new Dictionary<string, object>
            {
                { "name", "cheese" },
                { "value", "gouda" },
                { "domain", "www.selenium.dev" },
                { "secure", true }
            };
            ((ChromeDriver)driver).ExecuteCdpCommand("Network.setCookie", cookie);

View full example on GitHub

    driver.execute_cdp('Network.setCookie',
                       name: 'cheese',
                       value: 'gouda',
                       domain: 'www.selenium.dev',
                       secure: true)

View full example on GitHub

To make working with CDP easier, and to provide access to the more advanced features, Selenium bindings automatically generate classes and methods for the most common domains. CDP methods and implementations can change from version to version, though, so you want to keep the version of Chrome and the version of DevTools matching. Selenium supports the 3 most recent versions of Chrome at any given time, and tries to time releases to ensure that access to the latest versions are available.

This limitation provides additional challenges for several bindings, where dynamically generated CDP support requires users to regularly update their code to reference the proper version of CDP. In some cases an idealized implementation has been created that should work for any version of CDP without the user needing to change their code, but that is not always available.

Examples of how to use CDP in your Selenium tests can be found on the following pages, but we want to call out a couple commonly cited examples that are of limited practical value.

Geo Location — almost all sites use the IP address to determine physical location, so setting an emulated geolocation rarely has the desired effect.
Overriding Device Metrics — Chrome provides a great API for setting Mobile Emulation in the Options classes, which is generally superior to attempting to do this with CDP.

1 - Chrome DevTools Logging Features

Logging features using CDP.

While Selenium 4 provides direct access to the Chrome DevTools Protocol, these methods will eventually be removed when WebDriver BiDi implemented.

Console Logs

    ((HasLogEvents) driver).onLogEvent(consoleEvent(e -> messages.add(e.getMessages().get(0))));

View full example on GitHub

    async with driver.bidi_connection() as session:
        async with Log(driver, session).add_listener(Console.ALL) as messages:

View full example on GitHub

            using IJavaScriptEngine monitor = new JavaScriptEngine(driver);
            var messages = new List<string>();
            monitor.JavaScriptConsoleApiCalled += (_, e) =>
            {
                messages.Add(e.MessageContent);
            };
            await monitor.StartEventMonitoring();

View full example on GitHub

    driver.on_log_event(:console) { |log| logs << log.args.first }

View full example on GitHub

Implementation Missing

JavaScript Exceptions

Implementation Missing

    async with driver.bidi_connection() as session:
        async with Log(driver, session).add_js_error_listener() as messages:

View full example on GitHub

            using IJavaScriptEngine monitor = new JavaScriptEngine(driver);
            var messages = new List<string>();
            monitor.JavaScriptExceptionThrown += (_, e) =>
            {
                messages.Add(e.Message);
            };
            await monitor.StartEventMonitoring();

View full example on GitHub

    driver.on_log_event(:exception) { |exception| exceptions << exception }

View full example on GitHub

Implementation Missing

2 - Chrome DevTools Network Features

Network features using CDP.

While Selenium 4 provides direct access to the Chrome DevTools Protocol, these methods will eventually be removed when WebDriver BiDi implemented.

Basic authentication

Some applications make use of browser authentication to secure pages. It used to be common to handle them in the URL, but browsers stopped supporting this. With this code you can insert the credentials into the header when necessary

    Predicate<URI> uriPredicate = uri -> uri.toString().contains("herokuapp.com");
    Supplier<Credentials> authentication = UsernameAndPassword.of("admin", "admin");
    ((HasAuthentication) driver).register(uriPredicate, authentication);

View full example on GitHub

        credentials = base64.b64encode("admin:admin".encode()).decode()
        auth = {'authorization': 'Basic ' + credentials}
        await connection.session.execute(connection.devtools.network.set_extra_http_headers(Headers(auth)))

View full example on GitHub

            var handler = new NetworkAuthenticationHandler()
            {
                UriMatcher = uri => uri.AbsoluteUri.Contains("herokuapp"),
                Credentials = new PasswordCredentials("admin", "admin")
            };
            var networkInterceptor = driver.Manage().Network;
            networkInterceptor.AddAuthenticationHandler(handler);
            await networkInterceptor.StartMonitoring();

View full example on GitHub

    driver.register(username: 'admin',
                    password: 'admin',
                    uri: /herokuapp/)

View full example on GitHub

Implementation Missing

Implementation Missing

Network Interception

Both requests and responses can be recorded or transformed.

Response information

    try (NetworkInterceptor ignored =
        new NetworkInterceptor(
            driver,
            (Filter)
                next ->
                    req -> {
                      HttpResponse res = next.execute(req);
                      contentType.add(res.getHeader("Content-Type"));
                      return res;
                    })) {

View full example on GitHub

Implementation Missing

            INetwork networkInterceptor = driver.Manage().Network;
            networkInterceptor.NetworkResponseReceived += (_, e)  =>
            {
                contentType.Add(e.ResponseHeaders["content-type"]);
            };
            await networkInterceptor.StartMonitoring();

View full example on GitHub

    driver.intercept do |request, &continue|
      continue.call(request) do |response|
        content_type << response.headers['content-type']
      end
    end

View full example on GitHub

Implementation Missing

Response transformation

    try (NetworkInterceptor ignored =
        new NetworkInterceptor(
            driver,
            Route.matching(req -> true)
                .to(
                    () ->
                        req ->
                            new HttpResponse()
                                .setStatus(200)
                                .addHeader("Content-Type", MediaType.HTML_UTF_8.toString())
                                .setContent(Contents.utf8String("Creamy, delicious cheese!"))))) {

View full example on GitHub

Implementation Missing

            var handler = new NetworkResponseHandler()
            {
                ResponseMatcher = _ => true,
                ResponseTransformer = _ => new HttpResponseData
                {
                    StatusCode = 200,
                    Body = "Creamy, delicious cheese!"
                }
            };
            INetwork networkInterceptor = driver.Manage().Network;
            networkInterceptor.AddResponseHandler(handler);
            await networkInterceptor.StartMonitoring();

View full example on GitHub

    driver.intercept do |request, &continue|
      continue.call(request) do |response|
        response.body = 'Creamy, delicious cheese!' if request.url.include?('blank')
      end
    end

View full example on GitHub

Implementation Missing

Request interception

    try (NetworkInterceptor ignored =
        new NetworkInterceptor(
            driver,
            (Filter)
                next ->
                    req -> {
                      if (req.getUri().contains("one.js")) {
                        req =
                            new HttpRequest(
                                HttpMethod.GET, req.getUri().replace("one.js", "two.js"));
                      }
                      completed.set(true);
                      return next.execute(req);
                    })) {

View full example on GitHub

Implementation Missing

            var handler = new NetworkRequestHandler
            {
                RequestMatcher = request => request.Url.Contains("one.js"),
                RequestTransformer = request =>
                {
                    request.Url = request.Url.Replace("one", "two");

                    return request;
                }
            };
            INetwork networkInterceptor = driver.Manage().Network;
            networkInterceptor.AddRequestHandler(handler);
            await networkInterceptor.StartMonitoring();

View full example on GitHub

    driver.intercept do |request, &continue|
      uri = URI(request.url)
      request.url = uri.to_s.gsub('one', 'two') if uri.path&.end_with?('one.js')
      continue.call(request)
    end

View full example on GitHub

Implementation Missing

Performance Metrics

    devTools.send(Performance.enable(Optional.empty()));
    List<Metric> metricList = devTools.send(Performance.getMetrics());

View full example on GitHub

    async with driver.bidi_connection() as connection:
        await connection.session.execute(connection.devtools.performance.enable())
        metric_list = await connection.session.execute(connection.devtools.performance.get_metrics())

View full example on GitHub

            await domains.Performance.Enable(new OpenQA.Selenium.DevTools.V126.Performance.EnableCommandSettings());
            var metricsResponse =
                await session.SendCommand<GetMetricsCommandSettings, GetMetricsCommandResponse>(
                    new GetMetricsCommandSettings()
                );

View full example on GitHub

    driver.devtools.performance.enable
    metric_list = driver.devtools.performance.get_metrics.dig('result', 'metrics')

View full example on GitHub

Implementation Missing

Setting Cookies

    devTools.send(
            Network.setCookie(
                    "cheese",
                    "gouda",
                    Optional.empty(),
                    Optional.of("www.selenium.dev"),
                    Optional.empty(),
                    Optional.of(true),
                    Optional.empty(),
                    Optional.empty(),
                    Optional.empty(),
                    Optional.empty(),
                    Optional.empty(),
                    Optional.empty(),
                    Optional.empty(),
                    Optional.empty()));

View full example on GitHub

    async with driver.bidi_connection() as connection:
        execution = connection.devtools.network.set_cookie(
            name="cheese",
            value="gouda",
            domain="www.selenium.dev",
            secure=True
        )
        await connection.session.execute(execution)

View full example on GitHub

            var cookieCommandSettings = new SetCookieCommandSettings
            {
                Name = "cheese",
                Value = "gouda",
                Domain = "www.selenium.dev",
                Secure = true
            };
            await domains.Network.SetCookie(cookieCommandSettings);

View full example on GitHub

    driver.devtools.network.set_cookie(name: 'cheese',
                                       value: 'gouda',
                                       domain: 'www.selenium.dev',
                                       secure: true)

View full example on GitHub

Implementation Missing

Waiting for Downloads

    devTools.send(
            Browser.setDownloadBehavior(
                    Browser.SetDownloadBehaviorBehavior.ALLOWANDNAME,
                    Optional.empty(),
                    Optional.of(""),
                    Optional.of(true)));

View full example on GitHub

Implementation Missing

Implementation Missing

    driver.devtools.browser.set_download_behavior(behavior: 'allow',
                                                  download_path: '',
                                                  events_enabled: true)

    driver.devtools.browser.on(:download_progress) do |progress|
      @completed = progress['state'] == 'completed'
    end

View full example on GitHub

Implementation Missing

3 - Chrome DevTools Script Features

Script features using CDP.

While Selenium 4 provides direct access to the Chrome DevTools Protocol, these methods will eventually be removed when WebDriver BiDi implemented.

Script Pinning

    ScriptKey key = ((JavascriptExecutor) driver).pin("return arguments;");
    List<Object> arguments =
        (List<Object>) ((JavascriptExecutor) driver).executeScript(key, 1, true, element);

View full example on GitHub

Implementation Missing

            var key = await new JavaScriptEngine(driver).PinScript("return arguments;");
            var arguments = ((WebDriver)driver).ExecuteScript(key, 1, true, element);

View full example on GitHub

    key = driver.pin_script('return arguments;')
    arguments = driver.execute_script(key, 1, true, element)

View full example on GitHub

Implementation Missing

DOM Mutation Handlers

View full example on GitHub

            driver.get('https://www.selenium.dev/selenium/web/dynamic.html')
            driver.find_element(By.ID, "reveal").click()

View full example on GitHub

            using IJavaScriptEngine monitor = new JavaScriptEngine(driver);
            monitor.DomMutated += (_, e) =>
            {
                var locator = By.CssSelector($"*[data-__webdriver_id='{e.AttributeData.TargetId}']");
                mutations.Add(driver.FindElement(locator));
            };
            await monitor.StartEventMonitoring();
            await monitor.EnableDomMutationMonitoring();

View full example on GitHub

    driver.on_log_event(:mutation) { |mutation| mutations << mutation.element }

View full example on GitHub

Implementation Missing

Development Partners

Selenium Level Sponsors

Support the Selenium Project

Learn more or view the full list of sponsors.