Why Does Headless Mode Impact Puppeteer's Functionality on Some Websites?

Why Headless Mode Can Impact Puppeteer's Functionality

Puppeteer, a powerful tool for web scraping, by default operates in headless mode, meaning it executes tasks without opening a visible browser interface. However, certain websites may implement anti-scraping measures that detect headless browsers and prevent their access. This is why some users encounter issues with Puppeteer when using headless mode.

Understanding the Headless Mode Detection

Websites employ a range of techniques to identify headless browsers, including:

• UA (User Agent) detection
• Window dimensions
• DOM (Document Object Model) structure
• Lack of user interaction

Workarounds to Bypass Headless Mode Detection

1. Using Puppeteer-Extra Plugins:

Puppeteer-extra offers a range of plugins that can enhance Puppeteer's capabilities. Two plugins that may help overcomeheadless mode detection are:

• puppeteer-extra-plugin-anonymize-ua: Obfuscates the User Agent to avoid detection.
• puppeteer-extra-plugin-stealth: Implements evasion techniques to counter headless browser detection tricks.

2. Connecting to an Existing Chromium Instance:

Instead of launching Chromium headless, you can connect Puppeteer to an already-running browser instance. This requires:

• Starting Chromium with --remote-debugging-port=9222 (or any designated port)
• Using puppeteer to connect to the running instance: const browser = await puppeteer.connect({ browserURL: ENDPOINT_URL });

Endpoint_URL is displayed in the terminal when Chromium is launched with --remote-debugging-port=9222.

This approach involves server/ops configuration and may require additional troubleshooting.

Additional Considerations:

• Other anti-scraping techniques include blocking IP addresses, captcha challenges, and fingerprinting.
• Rotating IP addresses or using a proxy server can help mitigate IP blocking.
• Using a headless browser can still be effective for scraping some websites that do not have aggressive anti-scraping measures.

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