I’m building a web scraping application that needs to handle multiple concurrent requests. I’ve been looking for a headless browser solution that can work properly with threading.
So far I’ve tested several options but each has limitations:
- HtmlUnit doesn’t handle complex JavaScript well
- QWebPage from QtWebKit has thread safety issues
- PhantomJS requires spawning separate processes which isn’t ideal
- Awesomium also has threading problems
I need something that can execute JavaScript reliably while being safe to use across multiple threads. The browser instances should be creatable from different threads without conflicts.
Any programming language is fine as long as it meets these requirements. Has anyone found a solution that works well for multi-threaded web crawling scenarios?
Selenium WebDriver with Chrome in headless mode works great for this. WebDriver handles the process isolation automatically - each thread gets its own instance without any interference, and the Chrome processes stay completely separate. JavaScript execution is solid since you’re using a full browser engine. I use ThreadLocal variables so each thread keeps its own driver instance and there’s no cross-thread issues. Setup’s pretty straightforward - I’ve used it in both Java and Python for high-concurrency scraping and it works well.
Playwright’s perfect for this. I’ve been using it for the exact same thing. It was built for concurrency from day one - each browser context runs completely isolated, so you can spin up multiple instances across threads without any state conflicts. The JavaScript handling is solid since it uses actual browser engines. I’m running it in production right now with dozens of concurrent threads hitting JS-heavy sites, and none of the threading nightmares I had with QtWebKit. Plus you get Python, Node.js, and C# support, so you’re not locked into one language.
i’ve had good luck with headless chrome and puppeteer. it handles js nicely and i can run multiple instances without any headaches. just keep an eye on memory use when scaling up, though! works like a charm!