Python. Selenium. How to wait for new window opens?

Question

I have a button with twitter, and after click new window opens, but before opening there is a timout in few seconds, so is there a way to wait for it? I mait in a bad way for now...

    Ui.click_el(link.W9FormNodes.TWITTER_BUTTON)
    # Wait for new window and switch to it
    time.sleep(3)
    aw = driver.window_handles
    driver.switch_to_window(aw[1])

So I need something better, that will wait only that amount of seconds that needs.

I think I solve it in this way. But maybe someone will have comments how to do it better.

    aw = Ui.click_and_wait_for_window(link.W9FormNodes.TWITTER_BUTTON)
    driver.switch_to_window(aw[1])

And here is a method that click on button and wait for new window:

    def click_and_wait_for_window(self, node):
        current_value = old_value = self.driver.window_handles
        self.click_el(node)
        while len(current_value) == len(old_value):
            time.sleep(0.05)
            current_value = self.driver.window_handles
        return current_value

Answer 1

As Surya mentioned, WebDriverWait would be the way to wait for a change. You could have a context manager like this that only implements the wait logic and then use it for any kind of operation you care about:

@contextmanager
def wait_for_new_window(driver, timeout=10):
    handles_before = driver.window_handles
    yield
    WebDriverWait(driver, timeout).until(
        lambda driver: len(handles_before) != len(driver.window_handles))

Here's a full working example:

from selenium import webdriver
from selenium.webdriver.support.ui import WebDriverWait

from contextlib import contextmanager

@contextmanager
def wait_for_new_window(driver, timeout=10):
    handles_before = driver.window_handles
    yield
    WebDriverWait(driver, timeout).until(
        lambda driver: len(handles_before) != len(driver.window_handles))

driver = webdriver.Chrome()

driver.get("http://www.google.com")

with wait_for_new_window(driver):
    driver.execute_script("""
    window.open("http://www.google.com", "_blank");
    """)

with wait_for_new_window(driver, 2):
    pass # This will obviously hit the timeout.

driver.quit()