Selenium - Interact with exsting browser session using selenium-webdriver library in NodeJS

Question

http://tarunlalwani.com/post/reusing-existing-browser-session-selenium/

This post provides the insight for using existing session for selenium, but this is in Python/Java. Wanted to implement the same logic in NodeJS using selenium-webdriver library.

I am able to access the session id using:

    driver.getSession().then( function(session) {
         console.log('Session:'+session.getId());
    });

But how to get the executor value?

CHecked and found webdriver.WebDriver.attachToSession method will attach to the existing session, but need the value for executor and session for the same.

Answer 1

It is possible to attach to existing webdriver session with Node

You just need to create WebDriver object manually, without builder.

const _http = require('selenium-webdriver/http');

//todo: replace with your session ID and selenium url
let sessionId = 'cddab287623789c665c1dbc5c64bf702';
let url = 'http://localhost:4444/wd/hub';

let driver = new WebDriver(
    sessionId,
    new _http.Executor(Promise.resolve(url)
        .then(
            url => new _http.HttpClient(url, null, null))
    )
);

More complex example: test will try to use existing session, and if it does not work - will create a new one.

const {Builder, By, Key, until, WebDriver} = require('selenium-webdriver');
const _http = require('selenium-webdriver/http');

(async function example() {
    //todo: replace this value with session ID after test is executed first time
    let sessionId = 'cddab287623789c665c1dbc5c64bf702';
    let url = 'http://localhost:4444/wd/hub';
    let browser = 'chrome';
    let startUrl = 'http://www.google.com/ncr';

    //Connect to existing session
    let driver = await new WebDriver(
        sessionId,
        new _http.Executor(Promise.resolve(url)
            .then(
                url => new _http.HttpClient(url, null, null))
        )
    );

    //Trying to open URL. If does not work - we need to re-create a session
    await driver.get(startUrl).catch(async r => {
        console.log('Session "' + sessionId + '" not found. Creating new session.');
        driver = await new Builder()
            .usingServer(url)
            .forBrowser(browser)
            .build();
        driver.getSession().then(function(e){
            console.log('Session: ' + JSON.stringify(e, null, 2));
        });
        driver.get(startUrl);
    });

    console.log('Starting test execution');

    try {
        await driver.findElement(By.name('q')).sendKeys('webdriver', Key.RETURN);
        await driver.wait(until.titleIs('webdriver - Google Search'), 1000);
    } finally {
        //todo: We intentionally do not close the session in order to use it next time
        // await driver.quit();
    }
})();

Answer 2

In order to make it easier to start and reuse a WebDriver session I have created a script and packaged it in an NPM package so that you can start or reuse a WebDriver session in one command

npx webdriver-reuse-session

See the github readme for more information.

Then you can change the script from Maksym from

//todo: replace with your session ID and selenium URL
let sessionId = 'cddab287623789c665c1dbc5c64bf702';

TO

let sessionId = fs.readFileSync('.seleniumSessionId.txt')

And then this will be automatically updated, every time you start your test.

Hope this helps your or others out there.