C # - Selenium скриншот полной страницы

Question

Я бы хотел сделать полный снимок экрана, используя C # с Selenium и ChromeDriver. Здесь: https://stackoverflow.com/a/45201692/5400125 Я нашел пример, как это сделать на Java. Я пытаюсь добиться этого в C #, но я получаю исключение после загрузки страницы при первом вызове sendEvaluate:

OpenQA.Selenium.WebDriverException: 'нет такого сеанса (Информация о драйвере: chromedriver = 2.41.578737 (49da6702b16031c40d63e5618de03a32ff6c197e), платформа = Windows NT 10.0.17134 x86_64) '

public class ChromeDriverEx : ChromeDriver
{
    public ChromeDriverEx(string chromeDriverDirectory, ChromeOptions options)
        : base(chromeDriverDirectory, options, RemoteWebDriver.DefaultCommandTimeout)
    {
        var addCmd = this.GetType().BaseType
            .GetMethod("AddCustomChromeCommand", BindingFlags.NonPublic | BindingFlags.Instance);
        addCmd.Invoke(this,
            new object[] {"sendCommand", "POST", "/session/:sessionId/chromium/send_command_and_get_result"});
    }

    public void GetFullScreenshot()
    {
        Object metrics = sendEvaluate(
            @"({" +
            "width: Math.max(window.innerWidth,document.body.scrollWidth,document.documentElement.scrollWidth)|0," +
            "height: Math.max(window.innerHeight,document.body.scrollHeight,document.documentElement.scrollHeight)|0," +
            "deviceScaleFactor: window.devicePixelRatio || 1," +
            "mobile: typeof window.orientation !== 'undefined'" +
            "})");
    }

    private object sendEvaluate(string script)
    {
        var response = sendCommand("Runtime.evaulate",
            new Dictionary<string, object> {{"returnByValue", true}, {"expression", script}});
        return response;
    }

    private object sendCommand(string cmd, object param)
    {
        var r = this.Execute("sendCommand", new Dictionary<string, object> {{"cmd", cmd}, {"params", param}});
        return r.Value;
    }
}

И я называю это так:

 var opts = new ChromeOptions();
 opts.AddAdditionalCapability("useAutomationExtension", false);
 opts.AddArgument("disable-infobars");
 var driver = new ChromeDriverEx(".", opts);
 driver.Navigate().GoToUrl("https://stackoverflow.com/questions");
 driver.GetFullScreenshot();

Я использую Chrome 68 и ChromeDriver 2.41

Answer 1

Вот мой пример получения полноэкранного снимка экрана:

            string _currentPath = Path.GetDirectoryName(Assembly.GetAssembly(typeof(One of your objects)).Location) + @"\Attachs\";
            var filePath = _currentPath + sSName;

            if (!Directory.Exists(_currentPath))
                Directory.CreateDirectory(_currentPath);

            Dictionary<string, Object> metrics = new Dictionary<string, Object>();
            metrics["width"] = _driver.ExecuteScript("return Math.max(window.innerWidth,document.body.scrollWidth,document.documentElement.scrollWidth)");
            metrics["height"] = _driver.ExecuteScript("return Math.max(window.innerHeight,document.body.scrollHeight,document.documentElement.scrollHeight)");
            metrics["deviceScaleFactor"] = (double)_driver.ExecuteScript("return window.devicePixelRatio");
            metrics["mobile"] = _driver.ExecuteScript("return typeof window.orientation !== 'undefined'");
            _driver.ExecuteChromeCommand("Emulation.setDeviceMetricsOverride", metrics);

            _driver.GetScreenshot().SaveAsFile(filePath, ScreenshotImageFormat.Png);

            _driver.ExecuteChromeCommand("Emulation.clearDeviceMetricsOverride", new Dictionary<string, Object>());
            _driver.Close();

Answer 2

Этот код прекрасно работает при создании подкласса ChromeDriver. Обратите внимание, что приведенный ниже код специально написан в очень, очень многословном стиле, чтобы ясно проиллюстрировать каждую часть решения. Это можно легко написать более кратко, в зависимости от стиля кодирования и требований к надежной обработке ошибок. Более того, в будущем выпуске не будет необходимости создавать метод для выполнения команды DevTools, которая возвращает результат; такой метод уже будет частью привязки .NET.

public class ChromeDriverEx : ChromeDriver
{
    private const string SendChromeCommandWithResult = "sendChromeCommandWithResponse";
    private const string SendChromeCommandWithResultUrlTemplate = "/session/{sessionId}/chromium/send_command_and_get_result";

    public ChromeDriverEx(string chromeDriverDirectory, ChromeOptions options)
        : base(chromeDriverDirectory, options)
    {
        CommandInfo commandInfoToAdd = new CommandInfo(CommandInfo.PostCommand, SendChromeCommandWithResultUrlTemplate);
        this.CommandExecutor.CommandInfoRepository.TryAddCommand(SendChromeCommandWithResult, commandInfoToAdd);
    }

    public Screenshot GetFullPageScreenshot()
    {
        // Evaluate this only to get the object that the
        // Emulation.setDeviceMetricsOverride command will expect.
        // Note that we can use the already existing ExecuteChromeCommand
        // method to set and clear the device metrics, because there's no
        // return value that we care about.
        string metricsScript = @"({
width: Math.max(window.innerWidth,document.body.scrollWidth,document.documentElement.scrollWidth)|0,
height: Math.max(window.innerHeight,document.body.scrollHeight,document.documentElement.scrollHeight)|0,
deviceScaleFactor: window.devicePixelRatio || 1,
mobile: typeof window.orientation !== 'undefined'
})";
        Dictionary<string, object> metrics = this.EvaluateDevToolsScript(metricsScript);
        this.ExecuteChromeCommand("Emulation.setDeviceMetricsOverride", metrics);

        Dictionary<string, object> parameters = new Dictionary<string, object>();
        parameters["format"] = "png";
        parameters["fromSurface"] = true;
        object screenshotObject = this.ExecuteChromeCommandWithResult("Page.captureScreenshot", parameters);
        Dictionary<string, object> screenshotResult = screenshotObject as Dictionary<string, object>;
        string screenshotData = screenshotResult["data"] as string;

        this.ExecuteChromeCommand("Emulation.clearDeviceMetricsOverride", new Dictionary<string, object>());

        Screenshot screenshot = new Screenshot(screenshotData);
        return screenshot;
    }

    public object ExecuteChromeCommandWithResult(string commandName, Dictionary<string, object> commandParameters)
    {
        if (commandName == null)
        {
            throw new ArgumentNullException("commandName", "commandName must not be null");
        }

        Dictionary<string, object> parameters = new Dictionary<string, object>();
        parameters["cmd"] = commandName;
        parameters["params"] = commandParameters;
        Response response = this.Execute(SendChromeCommandWithResult, parameters);
        return response.Value;
    }

    private Dictionary<string, object> EvaluateDevToolsScript(string scriptToEvaluate)
    {
        // This code is predicated on knowing the structure of the returned
        // object as the result. In this case, we know that the object returned
        // has a "result" property which contains the actual value of the evaluated
        // script, and we expect the value of that "result" property to be an object
        // with a "value" property. Moreover, we are assuming the result will be
        // an "object" type (which translates to a C# Dictionary<string, object>).
        Dictionary<string, object> parameters = new Dictionary<string, object>();
        parameters["returnByValue"] = true;
        parameters["expression"] = scriptToEvaluate;
        object evaluateResultObject = this.ExecuteChromeCommandWithResult("Runtime.evaluate", parameters);
        Dictionary<string, object> evaluateResultDictionary = evaluateResultObject as Dictionary<string, object>;
        Dictionary<string, object> evaluateResult = evaluateResultDictionary["result"] as Dictionary<string, object>;

        // If we wanted to make this actually robust, we'd check the "type" property
        // of the result object before blindly casting to a dictionary.
        Dictionary<string, object> evaluateValue = evaluateResult["value"] as Dictionary<string, object>;
        return evaluateValue;
    }
}

Вы бы использовали этот код с чем-то вроде следующего:

ChromeOptions options = new ChromeOptions();
ChromeDriverEx driver = new ChromeDriverEx(@"C:\path\to\directory\of\chromedriver", options);
driver.Url = "https://stackoverflow.com/questions";

Screenshot screenshot = driver.GetFullPageScreenshot();
screenshot.SaveAsFile(@"C:\desired\screenshot\path\FullPageScreenshot.png");