Tuesday, August 30, 2011

Using add_cookie in Selenium 2

The documentation in the Python bindings for using the add_cookie() function Selenium 2 are unclear. The add_cookie() appears to take in a simple key/value pair:

def add_cookie(self, cookie_dict):
        """Adds a cookie to your current session.
            cookie_dict: A dictionary object, with the desired cookie name as the key, and
            the value being the desired contents.
            driver.add_cookie({'foo': 'bar',})
        self.execute(Command.ADD_COOKIE, {'cookie': cookie_dict})
If you're encountering NullPointerExceptions similar to a bug it's possible the problem is that your dictionary needs to include name, value, path, and secure keys. The tests in selenium/webdriver/common/cookies_test.py appear to back this point up:

self.COOKIE_A = {"name": "foo",
                         "value": "bar",
                         "path": "/",
                         "secure": False}

    def testAddCookie(self):
        self.driver.execute_script("return document.cookie")

Even the section posted at http://readthedocs.org/docs/selenium-python/en/latest/navigating.html#cookies suggest that adding cookie just a matter of connecting to using a key/value pair too:

Before we leave these next steps, you may be interested in understanding how to use cookies. First of all, you need to be on the domain that the cookie will be valid for:

# Go to the correct domain

# Now set the cookie. This one's valid for the entire domain
cookie = {"key": "value"})

# And now output all the available cookies for the current URL
all_cookies = driver.get_cookies()
for cookie_name, cookie_value in all_cookies.items():
    print "%s -> %s", cookie_name, cookie_value

For disabling the Django debug toolbar in Selenium 2, then the command should be:
self.selenium.add_cookie({"name" : "djdt",
                          "value" : "true",
                          "path" : "/",
                          "secure" : False})

As of Selenium v2.5.0, It appears that all name/value and secure must be specified to avoid triggering the NullPointerException error.

An issue report has been filed here:



  1. This was really useful. This saved me a headache! Thanks

  2. Likewise, thanks for this solution!