Develop Reference

Can I get the gecko driver to launch in an existing Firefox window?

I'm trying to use Selenium in Python to fill out a form, which is why I need it to run in an existing Firefox window where I'm logged in due to the sensitive login data. But I can't seem to find a way to prevent the driver launching in a new window where I am logged out. Is there a way to do this?
I've tried using options to set preference:
`from selenium.webdriver.firefox.options import Options
options = Options()
options.set_preference("browser.tabs.loadInBackground", False)
driver = webdriver.Firefox(options=options)`
I also tried using the -no-remote command on Firefox in cmd before running the script, but it didn't work either.

From chrome driver you can achieve this.
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
options = Options()
options.add_argument("user-data-dir=C:/Users/Designer1/AppData/Local/Google/Chrome/User Data/Profile 1")
driver = webdriver.Chrome(chrome_options=options,executable_path="C:\webdrivers\chromedriver.exe")

How to maximize chrome browser in default when using selenium in python

When I run chrome driver from selenium the browser opens in minimized windows. but I want it to open by default as maximized

You can either use
driver.maximize_window() or
chrome_options.add_argument("--start-maximized") which will maximize the browser when ever it opens.

The following code was taken from this link. https://pythonbasics.org/selenium-maximize/
from selenium import webdriver
import time
driver = webdriver.Firefox()
driver.maximize_window()
time.sleep(5)
driver.get("https://www.python.org")
This is one of the methods to do so.

How to initiate a Chromium based Vivaldi browser session using Selenium and Python

I am trying to use the vivaldi browser with Selenium. It is a chromium browser that runs very similar to chrome. I have Selenium working with Firefox (geckodriver), and Google Chrome(chromedriver), but I can't seem to find a way with Vivaldi. Any help would be appreciated.

If the vivaldi binary by default is located at C:\Users\levir\AppData\Local\Vivaldi\Application\vivaldi.exe you can use the following solution:
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
options = Options()
options.add_argument("start-maximized")
options.binary_location=r'C:\Users\levir\AppData\Local\Vivaldi\Application\vivaldi.exe'
driver = webdriver.Chrome(executable_path=r'C:\path\to\chromedriver.exe', options=options)
driver.get('http://google.com/')

For future reference:
to make Vivaldi work with selenium you need to make sure of three things :
The correct version of ChromeDriver
Set selenium's driver to use Vivaldi's binary via webdriver.ChromeOptions()
Make sure you're getting the correct url (don't forget "https://")
All of the above is explained step by step with screenshots in this blog post

The key executable_path will be deprecated in the upcoming releases of Selenium.
This post has the solution. I'm posting a copy of said solution with the path to Vivaldi, where the username is fetched by the script so you don't have to hard code it.
from selenium import webdriver
from selenium.webdriver.chrome.service import Service
import os
current_user = os.getlogin()
s = Service(rf"C:\Users\{current_user}\AppData\Local\Vivaldi\Application\vivaldi.exe")
driver = webdriver.Chrome(service=s)
driver.get("http://duckduckgo.com") # or your website of choice

You can use ChromeOptions and supply binary.
from selenium.webdriver.chrome.options import Options
opt = Options()
opt.binary_location = chromium_path//path to chromium binary
driver = webdriver.Chrome(options=opt, executable_path="path_to_chromedriver")

Headless Selenium suddenly stopped working

I have been using Selenium and python to web scrape for a couple of weeks now. It has been working fairly good. Been running on a macOS and windows 7. However all the sudden the headless web driver has stopped working. I have been using chromedriver with the following settings:
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
options = Options()
options.add_argument("--headless")
options.add_argument('--no-sandbox')
options.add_argument('--disable-gpu')
chrome_options.add_argument("--window-size=1920x1080")
driver = webdriver.Chrome(chrome_options=options)
driver.get('url')
Initially I had to add the window, gpu and sandbox arguments to get it work and it did work up until now. However, when running the script now it gets stuck at driver.get('url'). It doesn't produce an error or anything just seems to run indefinitely. When I run without headless and simply run:
from selenium import webdriver
driver = webdriver.Chrome()
driver.get('url')
it works exactly as intended. This problem is also isolated to my windows machine. Where do I start?

Solved
For some reason the proxy setting was slowing it down. Therefore it got solved by adding:
options.add_argument(f'--proxy-server={None}')

I had exactly the same problem. It appeared randomly after the script has run fine for weeks. OP has led me to the right direction, but his solution doesnt worked for me. I had to add:
chrome_options.add_argument("--no-proxy-server")
chrome_options.add_argument("--proxy-server='direct://'");
chrome_options.add_argument("--proxy-bypass-list=*");
My complete code:
chrome_options = Options()
chrome_options.add_argument("--headless")
chrome_options.add_argument("--start-maximized")
chrome_options.add_argument("--start-fullscreen")
chrome_options.add_argument("--no-proxy-server")
chrome_options.add_argument("--proxy-server='direct://'");
chrome_options.add_argument("--proxy-bypass-list=*");
chrome_options.binary_location = "C:\Program Files (x86)\Google\Chrome Dev\\Application\chrome.exe"
browser = webdriver.Chrome(options=chrome_options)
browser.set_window_size(2000, 1080)
please see also:
Headless chrome driver too slow
and:
Chrome webdriver produces timeout in selenium

Opening a web browser in full screen python

I am currently trying to code a basic smartmirror for my coding II class in high school with python. One thing I'm trying to do is open new tabs in full screen (using chrome). I currently have it so I can open url's, but I am not getting them in full screen. Any ideas on code I can use to open chrome in full screen?

If you're using selenium, just code like below:
from selenium import webdriver
driver = webdriver.Chrome()
driver.get('https://google.com')
driver.maximize_window()

As suggested, selenium is a good way to accomplish your task.
In order to have it full-screen and not only maximized I would use:
chrome_options.add_argument("--start-fullscreen");
or
chrome_options.add_argument("--kiosk");
First option emulates the F11 pressure and you can exit pressing F11. The second one turns your chrome in "kiosk" mode and you can exit pressing ALT+F4.
Other interesting flags are:
chrome_options.add_experimental_option("useAutomationExtension", False)
chrome_options.add_experimental_option("excludeSwitches", ["enable-automation"])
Those will remove the top bar exposed by the chrome driver saying it is a dev chrome version.
The complete script is:
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
chrome_options = Options()
chrome_options.add_experimental_option("useAutomationExtension", False)
chrome_options.add_experimental_option("excludeSwitches", ["enable-automation"])
# chrome_options.add_argument("--start-fullscreen");
chrome_options.add_argument("--kiosk");
driver = webdriver.Chrome(executable_path=rel("path/to/chromedriver"),
chrome_options=chrome_options)
driver.get('https://www.google.com')
"path/to/chromedriver" should point to the chrome driver compatible with your chrome version downloaded from here