Selenium WebDriver works but SLOW (Java)

问题:

I am using Selenium WebDriver to take a screenshot of webpages. It runs great. However, from the time I hit run in eclipse to the time the screenshot shows up in my local drive is 7-10 seconds. Most of the latency seems to be launching Firefox.

Code:

WebDriver driver = new FirefoxDriver();
driver.get("http://www.cnn.com");
File scrFile = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
FileUtils.copyFile(scrFile, new File("c:\\test\\screenshot.png"));

How can I speed up this process? Is there a way that I can use an already opened Firefox browser to save on opening a new one? Is this code somehow heavy?

Details: Tried on CentOS box and Win7 box both using eclipse. myspeedtest.net shows 22Mbps down and 1 Mbps up.

回答1:

What you are asking for (allowing WebDriver to attach to a running browser) has been an issue now for almost 3 years. To date, this feature has still not been added. As far as I am aware, there is no way to make Firefox load any faster. You can try a few other tricks though.

fp.setPreference("webdriver.load.strategy", "unstable")

Quoting the caveat from this page:

There is beta feature to make firefox not wait for the full page to load after calling .get or .click. This may cause immediate find's to break, so please be sure to use an implicit or explicit wait too. This is only available for Firefox and not other browsers.

You can also try loading with a profile and see if that helps at all.

回答2:

From the things I learned elsewhere -

1. Turn off automatic updates for your browser/plugins
2. Set your IIS (or equivalent) app timeouts to zero
3. Create a base Selenium Fixture for use in your tests
4. Update to the latest version of Selenium
5. Warm up your apps prior to testing
6. Short tests
7. Pre-populate cookies.

References:

https://sqa.stackexchange.com/questions/1988/selenium-reuse-existing-browser-session-instead-of-opening-new-windows

http://www.codeweavers.net/6-ways-to-speed-up-selenium-tests/

http://sauceio.com/index.php/2011/02/speed-up-your-selenium-tests/

Hope this helps!

回答3:

This thread shows a possible explanation.

To summarize, Selenium loops through all network cards and calls a method (getHostName) that takes a long time for virtual network cards. Disabling them solved the problem of the OP in the thread.

(In my own case, I am unable to disable any of them and have to wait at the start of each test case...)

回答4:

I realize that this question has already been answered, but I hope this helps anyone with the same problem.

If all you need to do is take screenshots. I recommend using Awesomium.NET. http://awesomium.com/

Doing this in C# rather than Java shouldn't be a major difficulty since they have similar syntax. It also supports C++ if you want to run your application on Linux. I presume it will be significantly faster than the WebDriver.

Use this if you choose C++: http://labs.awesomium.com/capturing-web-pages-with-c/

For C#.NET: http://awesomium.com/docs/1_7_rc3/sharp_api/

回答5:

For me it worked with 64bit version of IEDriverServer, I added the property requireWindowFocus with Value:"true".

DesiredCapabilities capabilities = DesiredCapabilities.internetExplorer();
capabilities.setCapability(InternetExplorerDriver.INTRODUCE_FLAKINESS_BY_IGNORING_SECURITY_DOMAINS, true);

capabilities.setCapability("requireWindowFocus", true);
WebDriver driver = new InternetExplorerDriver(capabilities);