I am writing some code to automate calculating certain page performance metrics. The results I am getting for page size are different by different methods:
What I want to achieve is to read these values shown in this screenshot:
Methods I am using:
Method giving different page load time and different transferred sizes: Totalbytes and NetData return very different numbers, both very far from what the screenshot would show
public void testing() throws HarReaderException {
JavascriptExecutor js1=((JavascriptExecutor)driver);
try {
Thread.sleep(5000);
}catch(Exception e) {e.printStackTrace();}
String url=driver.getCurrentUrl();
System.out.println("Current URL :"+url);
long pageLoadTime= (Long)js1.executeScript("return (window.performance.timing.loadEventEnd-window.performance.timing.responseStart)");
long TTFB= (Long)js1.executeScript("return (window.performance.timing.responseStart-window.performance.timing.navigationStart)");
long endtoendRespTime= (Long)js1.executeScript("return (window.performance.timing.loadEventEnd-window.performance.timing.navigationStart)");
Date date = new Date();
//Timestamp ts=new Timestamp(date.getTime());
System.out.println("PageLoadTime Time :"+pageLoadTime);
System.out.println("TTFB :"+TTFB);
System.out.println("Customer perceived Time :"+endtoendRespTime);
System.out.println("timeStamp");
String scriptToExecute = "var performance = window.performance || window.mozPerformance || window.msPerformance || window.webkitPerformance || {}; var network = performance.getEntries() || {}; return network;";
String netData = ((JavascriptExecutor)driver).executeScript(scriptToExecute).toString();
System.out.println("Net data: " + netData);
String anotherScript = "return performance\n" +
" .getEntriesByType(\"resource\")\n" +
" .map((x) => x.transferSize)\n" +
" .reduce((a, b) => (a + b), 0);"; //I have tried encodedSize here as well, still gives different results
System.out.println("THIS IS HOPEFULLY THE TOTAL TRANSFER SIZE " + js1.executeScript((anotherScript)).toString());
int totalBytes = 0;
for (LogEntry entry : driver.manage().logs().get(LogType.PERFORMANCE)) {
if (entry.getMessage().contains("Network.dataReceived")) {
Matcher dataLengthMatcher = Pattern.compile("dataLength\":(.*?),").matcher(entry.getMessage()); //I tried encodedLength and other methods but always get different results from the actual page
dataLengthMatcher.find();
totalBytes = totalBytes + Integer.parseInt(dataLengthMatcher.group(1));
//Do whatever you want with the data here.
}
}
System.out.println(totalBytes);
}
Setting up selenium Chrome driver, enabling performance logging and mobbrowser proxy:
@BeforeTest
public void setUp() {
// start the proxy
proxy = new BrowserMobProxyServer();
proxy.start(0);
//get the Selenium proxy object - org.openqa.selenium.Proxy;
Proxy seleniumProxy = ClientUtil.createSeleniumProxy(proxy);
// configure it as a desired capability
DesiredCapabilities capabilities = new DesiredCapabilities().chrome();
LoggingPreferences logPrefs = new LoggingPreferences();
logPrefs.enable(LogType.PERFORMANCE, Level.ALL);
capabilities.setCapability(CapabilityType.LOGGING_PREFS, logPrefs);
capabilities.setCapability(CapabilityType.PROXY, seleniumProxy);
ChromeOptions options = new ChromeOptions();
options.addArguments("--incognito");
capabilities.setCapability(ChromeOptions.CAPABILITY, options);
//set chromedriver system property
System.setProperty("webdriver.chrome.driver", driverPath);
driver = new ChromeDriver(capabilities);
// enable more detailed HAR capture, if desired (see CaptureType for the complete list)
proxy.enableHarCaptureTypes(CaptureType.REQUEST_CONTENT, CaptureType.RESPONSE_CONTENT);
}
Methods I am using to analyze the page: This method was supposed to show the Load Time in chrome inspector, but it is always showing a lesser number (I think it is showing the time of the last response received instead of DOMContentLoaded or Load Time)
public double calculatePageLoadTime(String filename) throws HarReaderException {
HarReader harReader = new HarReader();
de.sstoehr.harreader.model.Har har = harReader.readFromFile(new File(filename));
HarLog log = har.getLog();
// Access all pages elements as an object
long startTime = log.getPages().get(0).getStartedDateTime().getTime();
// Access all entries elements as an object
List<HarEntry> hentry = log.getEntries();
long loadTime = 0;
int entryIndex = 0;
//Output "response" code of entries.
for (HarEntry entry : hentry)
{
long entryLoadTime = entry.getStartedDateTime().getTime() + entry.getTime();
if(entryLoadTime > loadTime){
loadTime = entryLoadTime;
}
entryIndex++;
}
long loadTimeSpan = loadTime - startTime;
Double webLoadTime = ((double)loadTimeSpan) / 1000;
double webLoadTimeInSeconds = Math.round(webLoadTime * 100.0) / 100.0;
return webLoadTimeInSeconds;
}
I am getting the total number of requests by reading the HAR file from the page, but for some reason it is always 10% less then the actual:
public int getNumberRequests(String filename) throws HarReaderException {
HarReader harReader = new HarReader();
de.sstoehr.harreader.model.Har har = harReader.readFromFile(new File(filename));
HarLog log = har.getLog();
return log.getEntries().size();
}
Testing this on google gives very different results by each method, which are usually 10-200% off from correct numbers.
Why does this happen? Is there a simple way to get those metrics properly from Chrome or any library that makes this easier? My task is automate doing performance analysis on thousands of pages.
