Selenium use of Firefox profile

Question

I try to use Selenium Webdriver and Python on Windows 10 system to make some automation of browser actions. But I have this problem: Selenium-started Firefox window doesn't "see" that I am already logged in and target site sends me to login page. So I assumed that Selenium not really uses the profile, but just a copy of it.

I would like to know:

1. Is my conclusion about actual use of copy of profile true?
2. If 1. is true, is there a way to use really everything from existing profile?
3. If my conclusion is not true, please prove it and point me to the direction where I can find out what information can be used for session, why Selenium could fail to send it and how to force it to do so actually.

Edit:

from selenium import webdriver
fp = webdriver.FirefoxProfile('C:/Users/<user name>/AppData/Roaming/Mozilla/Firefox/Profiles/abc3defghij2.ProfileName')
driver = webdriver.Firefox(fp)
driver.get("https://www.example.com/membersarea")

Answer 1

Selenium indeed uses a copy of the profile, though that ought not to cause any problems. I think your issue has more to do with session cookies vs. persistent cookies.

On support.mozilla.org is a list indicating what information is actually stored in your profile. Note that cookies are among these, however session-cookies are not stored in cookies.sqlite which is the reason Selenium cannot rebuild your session since it does not appear in the profile.

Many sites, however, offer a remember-me or a stay-logged-in option on their login page which, if used, will store a persistent cookie by which the session can be restored. I used the following script to test this out with gmail,

from selenium import webdriver

url = "https://mail.google.com"
fp = webdriver.FirefoxProfile('/Users/<username>/Library/Application Support/Firefox/Profiles/71v1uczn.default')

driver = webdriver.Firefox(fp)
driver.get(url)

When I run this script after having logged into gmail with the stay-logged-in option enabled, then Selenium is able to access my inbox. If the stay-logged-in option is not enabled the session is destroyed upon closing my browser and thus Selenium cannot restore it either.

The screenshot below shows that session cookies are indeed not stored in cookies.sqlite and thus do not appear in the profile when used by Selenium.