Can Selenium interact with an existing browser session?

Question

Does anybody know if Selenium (WebDriver preferably) is able to communicate with and act through a browser that is already running before launching a Selenium Client?

Answer 1

It appears that this feature is not officially supported by selenium. But, Tarun Lalwani has created working Java code to provide the feature. Refer - http://tarunlalwani.com/post/reusing-existing-browser-session-selenium-java/

Here is the working sample code, copied from the above link:

public static RemoteWebDriver createDriverFromSession(final SessionId sessionId, URL command_executor){
    CommandExecutor executor = new HttpCommandExecutor(command_executor) {

    @Override
    public Response execute(Command command) throws IOException {
        Response response = null;
        if (command.getName() == "newSession") {
            response = new Response();
            response.setSessionId(sessionId.toString());
            response.setStatus(0);
            response.setValue(Collections.emptyMap());

            try {
                Field commandCodec = null;
                commandCodec = this.getClass().getSuperclass().getDeclaredField("commandCodec");
                commandCodec.setAccessible(true);
                commandCodec.set(this, new W3CHttpCommandCodec());

                Field responseCodec = null;
                responseCodec = this.getClass().getSuperclass().getDeclaredField("responseCodec");
                responseCodec.setAccessible(true);
                responseCodec.set(this, new W3CHttpResponseCodec());
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }

        } else {
            response = super.execute(command);
        }
        return response;
    }
    };

    return new RemoteWebDriver(executor, new DesiredCapabilities());
}

public static void main(String [] args) {

    ChromeDriver driver = new ChromeDriver();
    HttpCommandExecutor executor = (HttpCommandExecutor) driver.getCommandExecutor();
    URL url = executor.getAddressOfRemoteServer();
    SessionId session_id = driver.getSessionId();


    RemoteWebDriver driver2 = createDriverFromSession(session_id, url);
    driver2.get("http://tarunlalwani.com");
}

Your test needs to have a RemoteWebDriver created from an existing browser session. To create that Driver, you only need to know the "session info", i.e. address of the server (local in our case) where the browser is running and the browser session id. To get these details, we can create one browser session with selenium, open the desired page, and then finally run the actual test script.

I don't know if there is a way to get session info for a session which was not created by selenium.

Here is an example of session info:

Address of remote server : http://localhost:24266. The port number is different for each session. Session Id : 534c7b561aacdd6dc319f60fed27d9d6.