Can I use extensions with Headless Chromium?

Yes, you can use extensions with Headless Chromium, but it's not as straightforward as using extensions within a regular (non-headless) browser. Chrome extensions typically rely on a graphical user interface, which is not present in headless mode. However, there are some workarounds you can use to load extensions in headless mode, primarily for the purpose of running automated tests or performing tasks that don't require a UI.

Here's an example of how you can use extensions with Headless Chromium using Selenium and Python:

1. First, you need to have Selenium installed. If you haven't installed it yet, you can do so using pip:

pip install selenium

1. Then, you need to download the ChromeDriver executable that matches the version of the Chrome browser you're using. Make sure to place it in a directory that is in your system's PATH, or provide the path to it directly in your code.

2. Now, you can write a Python script to launch Headless Chromium with an extension:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
from selenium.webdriver.chrome.service import Service

# Path to your extension's folder (unpacked extension).
extension_path = '/path/to/your/extension/'

# Set up Chrome options.
chrome_options = Options()
chrome_options.add_argument('--headless')
chrome_options.add_argument('--disable-gpu')
chrome_options.add_argument(f'--load-extension={extension_path}')

# Set the path to the chromedriver you downloaded
service = Service('/path/to/chromedriver')

# Initialize the driver with the specified options.
driver = webdriver.Chrome(service=service, options=chrome_options)

# Your headless Chromium is now running with the extension.
# Perform your automation tasks here.

# Quit the driver when done.
driver.quit()

In the above script, replace '/path/to/your/extension/' with the actual path to your unpacked extension directory, and replace '/path/to/chromedriver' with the path to your ChromeDriver executable. The extension should be in an unpacked state, meaning it's a directory containing the extension's files, including the manifest file.

Running extensions in headless mode has limitations, especially if the extension requires user interaction or depends on the browser UI to function properly. Some extensions may not work as expected, or at all, in a headless environment. If you need to test or use such extensions, you may need to run Chromium in headful mode (with a GUI) instead.

For JavaScript or other languages, the process would be similar: set up a browser automation tool like Puppeteer (for JavaScript) with the appropriate flags to load the extension when launching the browser instance. Here's an example of how you might do this in JavaScript with Puppeteer:

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch({
    headless: false, // Currently, Puppeteer only supports loading extensions in headful mode
    args: [
      `--disable-extensions-except=/path/to/your/extension/`,
      `--load-extension=/path/to/your/extension/`
    ]
  });

  // Perform your automation tasks here.

  await browser.close();
})();

In this JavaScript example, Puppeteer is used to launch Chrome with the specified extension. Note that Puppeteer only supports loading extensions in headful mode as of my last update in 2023. If this has changed, please refer to the latest Puppeteer documentation for updates.