What is screen scraping and how it works

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Screen scraping is a technique used to extract data directly from the display interface, which can include texts, .doc files, UI elements, screenshots, media content, and recordings of user sessions. This method is primarily used in marketing to gather data for monitoring and analyzing reviews, market prices, advertising verification, and competitor analysis in e-commerce.

This technology can be executed manually or automated. Typically, the term "scraping" refers to the automated gathering of information, enabling the rapid processing of large volumes of data through specialized bots.

The primary benefits of scraping include:

  • Automating repetitive, routine tasks that would otherwise take much longer if performed manually.
  • Saving time through automation.
  • Ensuring data accuracy, as it eliminates errors that can occur with manual data collection and entry.
  • Aggregating data by gathering information from various sources and combining it.

Screen scraping emerged as a solution for transferring information from legacy systems, especially when updating software solutions was not feasible. By using screen scraping, data can be extracted from old systems and transferred to new ones.

Use cases for screen scraping

Screen scraping is employed when data cannot be harvested using conventional web scraping techniques due to the specific characteristics of a website or application. Scenarios where screen scraping is particularly effective include:

  1. On pages featuring dynamic content loaded through JavaScript or AJAX requests.
  2. On websites with anti-scraping protections, such as CAPTCHA, IP address blocking, or other technical barriers that prevent standard scraping.
  3. On web pages where data is displayed as images or other graphical elements that are not amenable to typical web scraping methods.
  4. On sites or web applications lack an API for data access, rendering web scraping ineffective.

However, it is crucial to acknowledge that screen scraping is not a one-size-fits-all solution for data collection and differs significantly from standard web scraping. Therefore, integrating both methods can often be more effective than using them individually.

Comparing screen scraping and web scraping

First, the technologies differ in the type of data they can extract. Web scraping tools are designed to scrape websites and can capture URLs, text, videos, and images, often using just a simple online web scraper. In contrast, screen scraping tools are only capable of capturing data that appears on screen as it is displayed in websites, documents, and applications, including text, charts, graphs, and images.

Below is a comparison table outlining the main differences between screen scraping and web scraping:

Feature Web scraping Screen scraping
Type of data collected Structured data from websites such as text, links, images, and product prices Both structured and unstructured data are available only through a visual interface
Data source Websites Applications, web pages, PDF documents
Data collection methods Downloading the HTML code of the webpage and parsing it with tools like BeautifulSoup or Scrapy in Python Analyzing displayed information on the screen, often using tools to automate browser interactions or capture screenshots
Use cases Data collection for analytics, price monitoring, product comparison, and information extraction for database creation Automation of interactions with applications and physical data sources on web pages not designed for data extraction
Speed of execution High speed, especially when making parallel requests to servers Generally slower due to the need for initiating actions such as page loading, data entry

Using proxies in screen scraping

Data extraction often involves automated processes, and websites may restrict such activity on their pages. Using a proxy during screen scraping can provide several benefits:

  • Bypassing blocking and rate limiting: common challenges in web scraping include rate limiting of requests from a single IP address and outright IP blocking due to high traffic. Proxies can help distribute requests across multiple IP addresses, significantly reducing the likelihood of being blocked.
  • Masking the real IP address: high-frequency requests can alert site administrators, leading to potential blocks. Using a proxy helps conceal your actual IP address, protecting your activities from detection.
  • Geo distribution: some websites restrict content access based on the user's geographic location. Proxies enable access to content from various regions by using IP addresses from those locations, allowing you to bypass regional restrictions.
  • Improved speed and performance: selecting proxies with good connection speeds, such as ISP or residential proxies, can enhance the efficiency and speed of your web scraping operations.
  • Improved security: many proxies offer additional security features, including traffic encryption and filtering of malicious requests, which bolster your data security during the scraping process.

There are several types of proxies available for use: server-based, mobile, and residential. Server-based proxies are faster but often face more frequent access restrictions on websites. Mobile and residential proxies typically offer better protection from blocking, making them more reliable for certain applications.

In today's technology landscape, data collection is a crucial process that can drive business growth. Screen scraping, when paired with proxy servers, becomes a potent tool that enhances security and effectiveness.

It's important to distinguish between screen scraping and web scraping, as they collect different types of information. Nonetheless, businesses can leverage both technologies concurrently to maximize the benefits of data extraction and boost the efficiency of their operations.