Web scraping is a unique technique for retrieving information from websites, frequently using automated programs or web bots. These scraping tools often leave basic or detailed digital footprints from the characteristics and interactions of the visitors with the website. Anti-scraping services utilized by sites examine such activities to differentiate the type of user and, as a result, either allow or deny access to the website. With these measures in place, the scraping process doesn’t always deliver the desired results, which might negatively affect the business’s overall progress and success.
In this post, we have covered how websites prevent data retrieval, as well as some valuable ways to achieve a maximum success rate when scraping.
How Sites Detect Web Scrapers
In the age of content, websites have become more intelligent and are coming up with many different methods to address data scraping attacks. Here is how sites are detecting bots and preventing web scraping:
Server-side Bot Detection
Bot detection occurs at the web server end using applications or a web service provider since all the traffic is routed through either one of these, and only legitimate users are permitted to access the original web server. Websites achieve such detection in the following ways:
HTTP Fingerprinting
It’s done by scanning basic information sent by a web browser, including user agent, browser encoding, request headers, etc.
TCP/IP Fingerprinting
Data is sent to a server as packets over TCP/IP, which contains initial packet size, TTL, segment size, window scaling value, etc. These details come together to form a unique identity of a machine, helping in finding a bot as a result.
Web Activity Tracking and Pattern Detection
As a next step, bot detectors can monitor user activities on a site using the same detecting services. If there is any oddity, a user is identified as a bot and is asked to solve a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) test. In case of failure, a user can be flagged/blocked.
Client-side Bot Detection
Because of its ease of use, client-side bot detection is more widely used. For example, it can easily detect a bot if the coming request can’t render a block of JavaScript. The detection occurs by creating a fingerprint with multiple attributes of a real browser, like user agent, supported HTML5 features and CSS rules, operating system, number of CPU cores and touchpoints, etc.
5 Best Ways To Increase Web Scraping Success
Akin to websites that have become smarter in bot detection, web scrapers have also learned the tactics of mimicking human-like behavior. Since it’s a continuous fight between websites and scraping bots, both are on the run to develop new ways to counter each other. Here are the top five ways following which you can bypass all the checkpoints set by a site:
Make Use of Headless Browsers
Servers find no difficulty telling whether a request is from a genuine browser using web fonts, browser cookies, extensions, and JavaScript execution. To improve your scraping capabilities, you should deploy headless browsers. With tools like Selenium or Puppeteer, you can code and manage these browsers that imitate real-user behavior. Some examples of headless browsers include Chromium, Playwright, Firefox, and more.
Rotate between Common User Agents
The website will likely block requests if there is no user agent (a string of data like type of application, OS, or software version) set or multiple requests are made via the same user agent time and again. Such a situation is avoidable if a pool of user agents is created, which are then rotated. With this, it appears to the website that various users are visiting from different geographic locations and browsers. You should rotate the whole set of headers and the user agents for even better results.
Hide and Control Digital Fingerprint
At times, the system fails to detect web scraping anomalies using IP addresses. So, fingerprinting is instead used to obtain information about browser attributes for user identification. Many tools, like Kameleo, GoLogin, and VMlogin, can help conceal and manage browser fingerprints which can interfere with the web scraping process.
For example, GoLogin is an anti-detection software that mimics the browser setting that a site can see. One of its core features is the integration of proxies with this application for the best browsing experience. Though it doesn’t offer proxy servers by itself, you can integrate residential or shared datacenter proxies to modify your browser fingerprinting whenever you want with GoLogin. You can find more in a blog post about proxy integration with GoLogin.
Utilize CAPTCHA-Solving Services
As mentioned earlier, websites often use CAPTCHA services to prevent web scraping. In order to scrape data successfully, advanced procedures need CAPTCHA-solving services. These are quite reasonable and can pass the tests with great ease. However, implement them first to solve tests served by your target sites or pages to measure their effectiveness.
Turn to Caching to Reduce Needless Requests
Determining which site or pages a scraper has already visited can decrease the time it takes to end the scraping process. This is where scrapers use caching of HTTP requests. You can avoid unwanted requests by caching pages.
The loose scraping bot logic during paginations also leads to unnecessary requests. So, search for combinations providing your desired maximum coverage instead of forcing any combinations. With the optimization of scraper logic, the likelihood of generating unneeded requests reduces, thereby saving you from bot detection.
Final Thoughts
The process of web scraping provides access to loads of information useful in making data-driven decisions. This helps put businesses on the road to success. While different websites use different tactics, you can follow the approaches mentioned earlier to make the most of all the advantages scraping bots provide.