What is Scraping?
Scraping, also known as web scraping, refers to the technique or practice of extracting and gathering specific information from the content of websites. The term "scraping" originates from the English word "scrape," meaning "to scrape off" or "to remove." In the context of websites, scraping involves extracting information from the site.
Web scraping can target visible elements on a site as well as hidden data stored within the website. This includes text, images, videos, HTML code, CSS code, and more. The extraction is typically conducted by a computer program or bot, which interacts with websites as though it were a human user. The scraped data is then processed and used for various purposes.
Scraping vs. Crawling
Scraping is often confused with crawling, another technique involving websites. Crawling refers to systematically browsing through a website's HTML source for comprehensive data collection, often emphasizing "traversing" the site. In contrast, scraping focuses on extracting specific, essential information. For example, Google's search engine uses crawlers to index web pages, which is a prime example of crawling.
Web Scraping Use Cases
Common use cases for web scraping include:
- Collecting Contact Information: Extracting telephone numbers and email addresses stored in membership databases from e-commerce or subscription websites for use in marketing lists.
- Monitoring Search Rankings: Checking where a specific page of a company website ranks in search engines like Google and comparing it to competitors’ rankings.
- Collecting Product Prices and Reviews: Extracting product names, prices, and reviews from e-commerce websites for competitive analysis.
- Gathering Dynamic Data: Collecting real-time information such as hotel availability, auction price fluctuations, and stock prices to create new content or services.
Threats Arising from Web Scraping
While web scraping has legitimate use cases, it can also be exploited maliciously, posing risks for website operators such as personal information misuse and security breaches. Common threats include:
- Copyright Infringement through Unauthorized Data Upload: Scraping original images or content from websites and uploading them to other sites without permission can violate copyright, personal data protection, and intellectual property rights.
- Excessive Monitoring and Business Disruption: Excessively scraping competitor websites can degrade system performance or disrupt normal browsing and transactions. In some cases, malicious scraping aims to increase system operational costs.
- Phishing Scams: Scraped website data can be used to create fake phishing sites that mimic the original website, tricking users into entering sensitive information like credit card details.
Preventing Threats from Web Scraping
Web operators must proactively implement countermeasures against scraping threats. Key methods include:
- Implementing Bot Management Systems: Deploy systems that detect and block automated bots attempting to scrape data from websites or web applications. Some systems specifically prevent bots from extracting data, making it impossible for scrapers to use bots for data collection.
- Rate Limiting and Data Limiting:
- Rate Limiting: Restricts the number of actions a user can perform within a specific timeframe. For instance, unusually fast content requests can be flagged and limited as bot activity.
- Data Limiting: Caps the amount of data users can extract from a site, preventing excessive data collection while allowing normal access.
