Essential knowledge to master web scraping

Ability to use programming languages

Specifically, having a firm grasp of Python is important when you start to scrape as it is the most popular programming languages. It is easier and more productive to use data scraping on a Python website than any other programming language.  The code in Python is similar to how human thinks, so you won’t face many difficulties learning it.

Furthermore, knowing how to use Beautiful Soup is also necessary if you choose to use Python. Beautiful Soup is a third-party Python library from Crummy for pulling data out of HTML and XML files. It’s easy to use and has a broad variety of APIs that’ll help users to fetch the data. You can use the requests library to fetch an HTML page and then use the Beautiful Soup to parse that page.

Wintr - Web Scraping and proxy API

Know and respect robots.txt file

Almost every website has robots.txt file and understanding it is a must. This text file contains scores of regulations that web scrapers and site indexers should obey. For example, it contains which page you cannot visit with your bot or how many requests you could make per second and so forth. If you don’t obey the rules written in this text file, you will possibly not have to suffer from anything but you would be better off being ethical and respecting the regulations.

Get the basic idea of HTML, CSS

HTML stands for HyperText Markup Language. It is used to create content structure and meaning of the page by defining that content as, for example, headings, paragraphs, or images. Almost every website on the internet is written using HTML, so having an understanding of this enables you to extract specific HTML elements easily.

Meanwhile, CSS, or Cascading Style Sheets, is responsible for styling the appearance of content—using, for example, the layout, fonts or background colors.

How websites work

As is mentioned above, a website is just a bunch of HTML pages. It is simply a collection of web pages of codes which describes the layout, format and content on a page. A server is a computer connected to the internet, with software that allows it to store or host pieces of the website: the code, the images, the video clips, and other things that make up the website. The browser connects your computer to the server through an IP address. So any website that we see on the Internet is present on a computer somewhere. A web server is installed on that computer which serves HTML files when a request is made to that server.

The components of a web scraper

Web scraping is similar to the Extract-Transform-Load Process. Web Scrapers crawl the site,  fetches information from it, change it into an available structured format and loads it into a file or database for different uses.

A typical web scraper has the following components:

  • Web crawling
  • Data Parsing and Extraction
  • Data Cleaning and Transformation
  • Data Serialization and Storage

How do web scrapers work?

Step 1: A web scraper sends a request using the HTTP protocol to the targeted URL.

Step 2: It loads the entire HTML for the page that user aims to reach. Some modern scrapers will translate the entire website including CSS and JavaScript elements.

Step 3: The scraper will extract all the data on the page and specific data selected by the user before the project is carried out.

Suggestions

If you are struggling with completely new knowledge in web scraping, you can use web scraping tools to aid with your work. Octoparse, Parsehub, Scrapy, Diffbot, Cheerio, or Mozenda is so popular and facilitates web scraping without coding.

In addition, WINTR: https://www.wintr.com/ is also a powerful tool for your scraping. It is a web scraping and parsing service whose APIs allows companies and developers to turn any webpage into a custom dataset. It offers many services such as data scraping, data parsing, requests proxying and request customization. It is a comprehensive tool to help your web scraping become as easy pie.