What is Web Scraping and How to Use it
Table of Contents
What is Web Scraping?
In a nutshell, web scraping is the technique of extracting small to large amount of data from various websites. However, the data is extracted and saved to a local file in your computer or to a database in the spreadsheet format.
Data on most of the existing websites are able to view using a web browser on your computer; they do not offer the usability to save a copy of this data for our personal use. The only option then available is to manually copy and paste the data – a very tedious and heavy job which can take hours and hours and sometimes days to complete.
Web Scraping is a technique of automating this long process of copy pasting, so that instead of manually copying the data from various websites, the Web Scraping software will perform the same task within a fraction of the total time for you.
Web pages are built using text-based mark-up languages (HTML and XHTML). As those contains a huge source of useful data in the text form. However, most of the web pages are designed for human end-users and not for ease of automated usage. Because of this, tools and software’s that creates scrape web content.
Scraper on web is an Application Programming Interface (API) to extract data from a web site. Companies like Google, Amazon AWS and many more provide web scraping services, tools and public data available free of cost to end users.
WHAT DO I USE FOR WEB SCRAPING?
- Separate services that work through an API, several authorized service provider or have a web interface (DiffBot Embedly, etc).
- Various open source projects involved and implemented in different programming languages such as Python: Goose, Scrapy; PHP: Goutte; Ruby: Readability, Morph, etc).
Challenges in Web Scraping
- Most of the websites are simply having different layout-wise.
- Pros or Amateurs, not all web developers follow style guides. As a result, their code often contains various mistakes making it absolutely unreadable and difficult to understand for scrapers.
- The HTML5 built websites contains many unique elements.
A web scraping software will automatically extract and load data from multiple pages of lots of websites based on your needs and requirement. It is either custom built for a specific website or the one which can configure according to work done with any website. With a click of a button you can easily save the data available in the website to a file in your computer.
The problem with most web scraping software is that they are very difficult to setup and use. There is a steep learning curve involves in setting up software and using it. Sometimes even the best web-scraping technology and unable to replace a human’s manual thinking process. when the websites for scraping definite set up various barriers to prevent machine automation. The copy-and-paste is sometimes the only workable solution.
Web Scraping!! How it’s DONE
Firstly, you need to create a mechanism to receive HTML code with a GET request. Next step is to inspect the DOM structure of the website to identify the nodes containing the required target data. After that, create a node processor to give output of the data in a specific format. The choice of format is usually based on either client’s requirements or your data processing preferences that you follow.
For example, we use JSON. And that’s how you can make and create your own Scraping system.
Now, let’s break it down into steps. The system receives an URL at the input and outputs stabilize the data at the output. Upon receiving the URL, the system decides which reader should process it. The priority goes to the most high-quality reader with proper customization’s which he can control. In case, if there is no intermediate the URL will forward to the default reader. Usually, it’s some third-party service
Uses of Web Scraping
Web scraping can use in a variety of digital businesses that rely fully on data harvesting. Authorized and Legitimate cases include:
- Search engine bots crawling site to site, analyzing its content and then ranking it accordingly.
- Price comparing sites putting bots to auto-fetch prices and product descriptions for allied seller websites.
- Market research companies using scrapers to pull out data from different forums and social media sites for sentiment analysis
There are also illegal purpose uses of web scraping. Including the undercutting of prices and the theft of online published copyright content. If a free scraper targets online sites and forum, this can suffer huge financial losses. Especially, if it’s a business strongly dependent upon competitive pricing models or deals in content distribution.
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