Chrome Driver Environment Setup

For setting up Chrome driver environment, ensure that the Chrome browser version matches the driver version. This guide assumes Chrome version 120 and its compatible driver. A straightforward method is used, which is verified to work for versions up to 120.

Launching Chrome with Persistent Cache

Using a cached session allows Selenium to mimic a manual opened browser instance, preserving user data and login states.

Configuration for Cache-Preserving Launch

To launch Chrome with existing cache data, first locate the Chrome user data directory using chrome://version/. Use only the path up to the User Data folder.

chrome_data_path = r'C:\Users\Cassie\AppData\Local\Google\Chrome\User Data'
options = webdriver.ChromeOptions()
options.add_argument('--user-data-dir=' + chrome_data_path)
driver = webdriver.Chrome(executable_path=chromedriver_path, options=options)

Automatically Closing Existing Browser Instances

Before launching a new instance, ensure no existing Chrome or Chromedriver processes are running:

os.system('taskkill /im chromedriver.exe /F')
os.system('taskkill /im chrome.exe /F')

Suppressing Chrome Crash Recovery Prompt

Upon restart, Chrome may show a crash recovery prompt. This is resolved by modifying the Preferences file to indicate a normal exit:

def set_exit_normal():
    preferences_path = os.getenv("LOCALAPPDATA") + r'\Google\Chrome\User Data\Default\Preferences'
    with open(preferences_path, 'r', encoding='utf8') as pf:
        preferences = json.loads(pf.read())
    preferences['profile']['exit_type'] = 'Normal'
    with open(preferences_path, 'w', encoding='utf8') as pf:
        pf.write(json.dumps(preferences, ensure_ascii=False, separators=(',', ':')))

Final Implementation

Driver Utility Module

The following module provides two methods for launching Chrome: standard or with persistent cache:

import json
import os
from selenium import webdriver

chromedriver_path = r"C:\Program Files\Google\Chrome\Application\chromedriver.exe"
chrome_data_path = r'C:\Users\Cassie\AppData\Local\Google\Chrome\User Data'

def set_exit_normal():
    preferences_path = os.getenv("LOCALAPPDATA") + r'\Google\Chrome\User Data\Default\Preferences'
    with open(preferences_path, 'r', encoding='utf8') as pf:
        preferences = json.loads(pf.read())
    preferences['profile']['exit_type'] = 'Normal'
    with open(preferences_path, 'w', encoding='utf8') as pf:
        pf.write(json.dumps(preferences, ensure_ascii=False, separators=(',', ':')))

def kill_chrome():
    set_exit_normal()
    os.system('taskkill /im chromedriver.exe /F')
    os.system('taskkill /im chrome.exe /F')

def drivers(cache=False):
    if not cache:
        return webdriver.Chrome(chromedriver_path)
    else:
        options = webdriver.ChromeOptions()
        options.add_argument('--user-data-dir=' + chrome_data_path)
        return webdriver.Chrome(executable_path=chromedriver_path, options=options)

Usage Example

from time import sleep
from driver_ import drivers, kill_chrome

try:
    driver = drivers(True)
except:
    kill_chrome()
    driver = drivers(True)
    sleep(2)
driver.get('https://blog.csdn.net/aaaaaaaaanjjj')

Dependencies and Packaging

• Python 3.7
• Selenium
• Chrome version 120

Disabling Chrome Auto-Udpate

Two methods are available to prevent automatic updates:

1. Modify group policy settings to disable automatic updates.
2. Rename the GoogleUpdate.exe file located in the Google Update directory (e.g., C:\Users\lenovo\AppData\Local\Google\Update). Note that this may prevent critical security updates from being applied.