How to Deal With the Most Common Challenges in Web Scraping
For those who practice data extraction as an essential business tactic, we’ve revealed the most common web scraping challenges.
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In the world of business, big data is key to competitors, customer preferences, and market trends. Therefore, web scraping is getting more and more popular. By using web scraping solutions, businesses get competitive advantages in the market. The reasons are many, but the most obvious are customer behavior research, price and product optimization, lead generation, and competitor monitoring. For those who practice data extraction as an essential business tactic, we’ve revealed the most common web scraping challenges.
From time to time, some websites are subject to structural changes or modifications to provide a better user experience. This may be a real challenge for scrapers, who may have been initially set up for certain designs. Hence, some changes will not allow them to work properly. Even in the case of a minor change, web scrapers need to be set up along with the web page changes. Such issues are resolved by constant monitoring and timely adjustments and set-ups.
When you deal with very large websites comprising 1000 and more pages like e-Commerce, be ready to face the challenge of different pages having different HTML coding. It’s a common threat if the development process lasted for a long time and the coding team was changed by perforce. Here, the parsers should be set accordingly for all pages and, of course, changed in case of necessity. The solution is to scan the entire website to find the differences in the coding, then act as required.
Big data web scraping may affect website performance or even take it down. To avoid overloading, you need to keep scraping time balanced. The only way to make proper estimations for defining the time limits is testing what is necessary to do by checking the site’s endurance before starting data extraction.
Legal issues in web scraping pose a very delicate challenge․ Though it is legal, commercial usage of extracted data is restricted. It depends on the situation and type of information you are extracting and how you are going to use it. To learn about all pain points related to web scraping legality, read the A Comprehensive Overview of Web Scraping Legality: Frequent Issues, Major Laws, Notable Cases blog post.
With the growing demand for web scraping services, anti-scraping technologies have been developed accordingly. Prevention from scraping attempts ensures the proper function of sites and protects them from going down. This restriction comes up in the form of bot detection, captcha usage, IP blocking, etc. You are lucky if you find a web crawler provider that can accept this challenge. Let’s go through the most common dilemmas.
Professional Protection Through Imperva and Akamai
There are two giants that offer professional protection services: Imperva and Akamai. As anti-scraping techniques, they provide bot detection services and solutions for auto-substitution of content.
By using bot detection, it becomes possible to distinguish web crawlers from human visitors, thus protecting web pages from parsing information. But professional web scrapers can simulate human behavior perfectly today. Using real, registered accounts or mobile devices also helps to outwit anti-scraping traps.
In case of auto-substitution of content, the scraped data may be displayed in mirror image or the text may be generated in hieroglyphics font. This challenge is resolved with special tools and timely checking.
Captcha Resolving Challenge
You’ve probably noticed captcha requests on many web pages that are used to separate humans from crawling tools with the help of logical tasks or a request for the user to type the displayed characters. Now, the challenge to resolve captcha becomes easier through special open-source tools, and there are even crawling services that have developed their own tools to pass this check. For example, to pass the captcha on some Chinese sites is sometimes a hard task even for humans, and at DataOx there are specialists who pass them manually.
IP Blocking Challenge
IP blocking is another common method to fight against scrapers. It works when a website detects lots of crawling attempts from the same IP address or when the requests are coming from IP addresses already registered in the blacklists. There is also IP blocking through geolocation when a site is protected from attempts from certain locations. To bypass these restrictions, crawling services use special solutions with proxy rotation possibilities.
Large-Scale and Real-Time Scraping
Extracting of a huge number of data in real time is another challenge. As parsers are constantly monitoring web pages, any instability might lead to breakdowns. This is a hard challenge to resolve, and web scraping gurus are constantly enhancing their technologies to overcome it and provide seamless data parsing in real time.
Data Quality Challenge
Data accuracy is also extremely important in web parsing. For example, extracted data may not match a pre-defined template, or the texting fields may not be filled properly. To ensure data quality, you need to run a quality assurance test and validate every field and phrase before saving. Some of these tests are done automatically, but there are cases when the inspection should be done manually.
Published at DZone with permission of Andrew Demchenko. See the original article here.
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