使用 JavaScript - Java - Selenium 以编程方式获取 HTML 元素的目标 URL

Question

有一个页面有很多指向任何地方的链接，但我无法获取目标 URL，因为在代码中似乎没有网址：

<li>
    <a href="javascript:void(0)">
        <span title="Text">Text</span>
    </a>
</li>

有大量的混淆代码。我最好的猜测是它可能会从微服务动态加载 URL。

有没有办法以编程方式获取元素的目标 URL，最好不用导航到链接？我正在尝试将 JavaScript / Selenium 与 Java 结合使用。

我在想，通过触发onclick 事件并在重定向之前的某个时间点获取 URL 可能是可能的。

Answer 1

我解决的问题如下：

1. 使用 JavaScript 代码 sn-p 重新定义浏览器的 window 对象的 open() 方法以获取目标 URL，将其存储在全局上下文中并防止重定向。 This question might help。
2. 触发点击 HTML 链接元素以运行底层 XMLHttpRequest 调用。
3. 使用 JavaScript 的 clearInterval() 和 Java 的 executeAsyncScript() 方法，观察一个全局变量，直到它的值被设置（值由点击元素后的 window.open() 方法设置）。

因为我用的是ChromeDriver，所以下面的例子是在谷歌浏览器上运行的

import java.io.IOException;
import org.openqa.selenium.By;
import org.openqa.selenium.ElementNotInteractableException;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.support.ui.WebDriverWait;

public class DeadLinkTest {

    private static WebDriver driver;
    private static WebDriverWait wait;
    private static JavascriptExecutor js;
    
    private static String driverAbsolutePath = "/chromedriver.exe";
    private static String profileDirectory = "/myprofile";
    //Look for a webpage that actually has elements like <a href='javascript:void(0);'> that causes redirection
    private static String starterUrl = "https://www.google.com/";

    //XPath for an element like <a href='javascript:void(0);'> 
    private static final String DEAD_LINKS_XPATH = "//a[starts-with(translate(normalize-space(@href),' ',''),'javascript:void')]";
    private static final String CLICK_ELEMENT_JS_CODE = "arguments[0].click();";
    private static final String DOCUMENT_READY_JS_CODE = "return document.readyState;";
    private static final String LINK_RESOURCE_URL_VAR_NAME = "window.redirectionUrl"; //global variable name
    private static final String PREPARE_BROWSER_FOR_URL_EXTRACTION_JS_CODE =
            "window.windowOpen = window.open;" + //backup original function
            "window.isRedirectionEnabled = false;" + //turn on/off redirection via global variable
            LINK_RESOURCE_URL_VAR_NAME + " = null;" + 
            "window.open = function() {" + //redifine open() method
            "    " + LINK_RESOURCE_URL_VAR_NAME + " = arguments[0];" + //put link's url into global variable
            "    if(window.isRedirectionEnabled) {" + 
            "        windowOpen.apply(this, arguments);" + 
            "    }" + 
            "};";
    private static final String GET_LINK_RESOURCE_URL_JS_CODE =
            "(function(seleniumCallback){" + //IIFE that recieves selenium's callback function from executeAsyncScript() method
            "    let intervalId = setInterval(function(){" + 
            "        if(" + LINK_RESOURCE_URL_VAR_NAME + ") {" + //check if global variable is still null
            "            clearInterval(intervalId);" + 
            "            let urlString = " + LINK_RESOURCE_URL_VAR_NAME + ";" + 
            "            " + LINK_RESOURCE_URL_VAR_NAME + " = null;" + //set global variable to default state
            "            seleniumCallback(urlString);" + //Send back the url to Java
            "        }" + 
            "    },0);" + 
            "}(arguments[0]));";

    public static ChromeDriver createChromeDriver() {
        ChromeOptions options = new ChromeOptions();
        options.addArguments("--user-data-dir=" + profileDirectory + "/AppData/Local/Google/Chrome/User Data/Profile 2");
        //options.addArguments("--profile-directory=Profile 2");
        options.addArguments("--start-maximized");
        //options.addArguments("--disable-extensions");
        //options.addArguments("--no-sandbox");
        System.setProperty("webdriver.chrome.driver", driverAbsolutePath);
        return new ChromeDriver(options);
    }

    public static void main(String[] args) throws IOException {

        driver = createChromeDriver();
        wait = new WebDriverWait(driver, 30);
        js = (JavascriptExecutor) driver;
        try {
            driver.manage().window().maximize();
            driver.get(starterUrl);
            wait.until(webDriver -> js.executeScript(DOCUMENT_READY_JS_CODE).toString().equals("complete")); //Checks that page is loaded
            
            js.executeScript(PREPARE_BROWSER_FOR_URL_EXTRACTION_JS_CODE); //Avoids redirection and prepares global variable
            WebElement deadLink = driver.findElement(By.xpath(DEAD_LINKS_XPATH));
            try {
                deadLink.click(); //Puts the link url into browser's global variable. See PREPARE_BROWSER_FOR_URL_EXTRACTION_JS_CODE
            } catch (ElementNotInteractableException e) {
                js.executeScript(CLICK_ELEMENT_JS_CODE, deadLink); //In case element is not clickable
            }
            String linkUrl = (String) js.executeAsyncScript(GET_LINK_RESOURCE_URL_JS_CODE);
            System.out.println(String.format("TARGET URL: %s", linkUrl));
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //driver.quit();
        }
    }
}