Headless Browser for Web Scraping: Usage Features

In this post, we share our fascination with Headless Browsers and recommend a suitable development library for your project. It might come in handy if you work in data science, website development and testing, SEO, and UX/UI design.

The cornerstone of any websites security measures is the ability to tell a human and a bot apart. Once a bot has been identified, its IP address is flagged and blocked. One way to recognize bots is to compare bot and human behavioral patterns. Even with advanced randomizers, bots cannot fully imitate humans natural imperfection and chaotic timing.

One common way of filtering bots out is a honeypot link. It is a security mechanism that creates a virtual trap to lure attackers. It is usually an invisible link requesting an activity people cant see it and, hence, dont click it, while bots programmed to act on any human activity, do. Once bots click such link, they are flagged and banned. One other is CAPTCHA: modern AI can tick checkboxes and recognize text, but the precise execution and repetition expose them as inhuman.

What is a Headless Browser?

Headless browsers get past the human or bot challenge by emulating human actions. They are used for automated website and web app browsing and interaction.

Headless browsers render web pages or app code into an interactive page a human normally sees. Headless browsers scroll websites, click buttons, download files, and solve JavaScript elements, so we no longer need to do it manually. They can type data into fields, complete forms, search, or go through a shopping workflow from beginning to end.

How are headless browsers different from regular browsers? Technologically, headless browsers are not much different from our normal Chrome or Firefox, except they do not have a human-facing User Interface (tabs, URL, etc.) and have added AI and automation features instead. You control headless browsers by writing scripts with instructions.

What Can a Headless Browser Be Used for?

Any task that involves long hours of scrolling and clicking through websites can benefit from automation. If it involves modern, dynamic websites, a headless browser might be necessary.

For Website Scraping
You do not need a headless browser if the websites you are scrolling are plain HTML/CSS pages, which are still very common. In that case, an HTML Web Scraper will be a simpler yet sufficient solution.

You need headless browser capability when dealing with dynamic pages, stateful code elements, and JavaScript controls. These website features make user experience more personalized, but, as a side effect, they interfere with the bots ability to do their job.

Headless browsers help to bypass Browser Fingerprinting, one of the anti-bot measures. Instead of relying just on IP address, Browser Fingerprinting looks at the entire combination of the timezone, device, screen resolution, JavaScript configuration, etc.

For Testing
UI testing is one of the first headless browser use cases. Performing multiple user interaction scenarios repeatedly and under different conditions can be daunting. Human imprecision can also contaminate some technical experiments and require many resources to load pressure-test. Headless browsers have to expose bugs and errors.

For User Journey Mapping
Using headless browsers, analysts can accumulate samples to compare different UI versions faster. Gathering data from human users can take weeks. Analysts can then compare and correct inefficient or unproductive workflows.

For Capturing Website Screenshots
Sometimes we need to capture website screenshots en masse for design analysis or aggregator previews. Most headless browser tools are well-capable of taking page screenshots and saving them as PDFs.

How to Choose the Best Headless Browser Library?

Headless browser functionality is now available for most major languages and browsers.

The most popular headless browser libraries are:

• Selenium is the umbrella name for the open-source browser automation tools, libraries, and extensions for both web and mobile. In addition to the typical headless browsing functionality, it offers a distribution server and implementation infrastructure. Selenium can handle JavaScript elements, Iframes, and certificate requirements. Its primary purpose is testing automation, but it serves web scraping well. Supported browsers: Chrome, Firefox, Opera, Edge, and Safari. Supported programming languages: Java, Python, CSharp, Ruby, JavaScript, Kotlin.
• Puppeteer by Google is a Node.js library providing an API for headless browser control via DevTools Protocol. Originally, it was an automated testing library, but it has been successfully used for web scraping. Supported browsers: Chrome / Chromium, limited Firefox. Supported programming languages: Node.js; has an unofficial Python library, Pyppeteer.
• Playwright.js by Microsoft is a recent alternative to Puppeteer. It positions itself as end-to-end testing for modern web apps. Its primary purpose is testing, and it has an excellent toolset, including the error tracer capable of capturing and investigating the test failure. The same rendering engine works for mobile browsers, desktop, and the cloud. Supported browsers: Chromium, Firefox, and WebKit. Supported programming languages: Playwright API can be used with TypeScript, JavaScript, Python, .NET, and Java.
• Kimurai is a Web Scraping framework for Ruby with headless browser functionality. Supported browsers: Chromium and Firefox. Supported programming languages: Ruby.

Important note: for testing and scraping headless, Proxy might be essential. Even advanced bots will be detected from time to time. You need to protect your own IP address from getting blocked. Similarly, you need a geo-enabled Proxy service to test geo-sensitive workflows or scrape geo-blocked information.

Headless browsers automate browsing whenever it might be required. Same as any automation, it is a smart effort and time-saving tool. No head no headache!

Choose a headless browser application or library that uses your programming language and the type of browser you need. Open-source Selenium, Puppeteer by Google, and Playwright by Microsoft are the most advanced headless browser libraries.

_This post was originally published on SOAX blog.
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