Web Scraping: How the Technology Works

You have likely heard about web scraping and its importance for business owners in obtaining information available on the Internet. Web scraping is an excellent way to collect data, but the information and its quality that you get will depend on the web scraping technology you choose.

In this article, we will look at web scraping, tools for scraping, how parsers work, types of web scrapers, and technologies used for scraping.

What is Web Scraping?

Web scraping is an automated process of obtaining huge amounts of data from websites. Data in HTML is mostly unstructured before it is transformed into a spreadsheet or database for further use in various applications. Web scraping can be carried out in various ways, and each has its advantages and disadvantages.

For example, you can use web services or APIs, or write your own web scraping programs from scratch. Using APIs, you can access structured data from many of the world's most popular sites, such as Google, StackOverflow, and Twitter.

This is the best choice. However, many other sites do not allow users to access significant amounts of structured data or are less advanced than this. In that case, web scraping is the best method to obtain data from a site.

Web scraping requires a crawler and a parser. To find the needed information, the crawler navigates links on the web and scans the relevant content.

The parser is designed to extract data from the web. The parser architecture can vary greatly depending on the complexity and scale of the project, so that data can be extracted quickly and accurately.

Basics of Web Scraping

This is a two-step process consisting of a web crawler and a parser. While the parser follows the crawler like a guide, the parser extracts the data it needs.

Crawler

When it comes to web crawlers, we call them "spiders". These are artificially created intelligent machines that use links and reconnaissance to find and index materials on the web. Often, to find URLs for your parser, you first need to "crawl" the entire web or a single page.

Parser

With a web parser, you can quickly and accurately collect data from a website. To find the data you want to parse from the HTML file, you need to use data locators such as CSS selectors, XPath, regex, or any combination of them.

Different Types of Web Scrapers

Web scrapers can be divided into custom and ready-made, browser extensions or software, cloud-based and local.

Custom Web Scraper

A custom parser allows you to quickly extract data from thousands of URLs using a single command line interface. With this method, you can extract data from any sources, even those not displayed in the browser. You can customize and build your own parser or seek help from data solution developers who will provide you with a parser that meets your requirements.

Web Scrapers as Browser Extensions

Web scrapers as browser extensions allow you to collect data from the Internet. They are easy to use because they are built into your browser, but this also limits their capabilities. Such web scrapers do not support any features beyond