Web scraping, also known as Screen Scraping, Web Data Extraction, or Web Harvesting, is a technique for extracting a large amount of data from websites saved to a local file in your computer or to a database in the form of a table. Web scraping is not as simple as it seems so. It can be done manually, but automated data scraping tools are mostly preferred because of their efficiency and low cost.
You can scrape websites on all levels using free scraper tools or proxy scraping techniques. Web Scraper tool is used to scrape webpages from different sites with several levels of navigation. It can smoothly run in the browser without any complicated installation requirements. Web Scraping is not only used to extract information from dynamic websites but can also scrape web items.
The data displayed on most of the websites are viewed through a web browser. They do not have any option to save a copy of this data for personal use. The only option left is to copy and paste the information manually, which can take many hours or even days and is a very tiresome job. Web Scraping is an automatic process in which “Web Scraping software” will perform the task of extracting the complete data within minutes instead of manually copying the data from websites.
Use of web scraping
Web scraping of the web pages involves web crawling, which means to fetch pages for later processing. Web scrapers extract something out of a page and make use of it for another purpose anywhere else. One example is contact scraping, in which names, addresses, email, phone numbers, or companies and their URLs are found and copied in the form of a list.
Web scraping is also used for web indexing, data and web mining, online price comparison with an amazon price scraper and price change monitoring, product review scraping, weather data monitoring, gathering real estate listings, research, website change detection, tracking online presence and reputation, web mashup, and web data integration. Other forms of web scraping include listening to data feeds from web servers.
However, some websites prevent web scraping by using some detecting techniques and prohibiting the user from fetching their web pages. In response to this, there is a Proxy scraping system that depends upon DOM parsing, natural language processing, and computer vision methods to simulate human browsing and enabling web page content gathering for offline parsing.
Methods of Web Scraping
The latest web scraping methods range from manual to completely automated systems that can convert the entire websites into organized information with limitations.
Copy and Paste
The most basic form of web scraping is to manually copy and paste the data from a web page into a text file or spreadsheet. It is seen that sometimes even the top web scraping tools cannot substitute human’s effort, and sometimes it is the only feasible solution when the websites are restricted against machine automation.
Text pattern matching
Another simple yet powerful method for mining information from websites is using UNIX-grep command or regular expression matching command of programming languages.
A developer can develop custom data extraction programs according to your specific requirement. The developer will make use of web scraping APIs to develop the software quickly. For instance, apify.com can help you to get APIs for scraping data from any website.
Numerous software tools are readily available to customize web-scraping solutions. This tool automatically identifies the data structure or provides a recorded interface that will eliminate manually writing web scraping code to extract, transform, and store the scraped data in local databases. There are some web scraping software that can be used to extract data directly from an API.
There are two main categories of Web Scraping software, one can be installed on your computer, and the other is a cloud data extraction platform. OutWit Hub, WebHarvy, Visual Web Ripper are some web scraping software that can be installed on your computer, whereas import.io, Mozenda are examples of the cloud-browser based.
There is a long list of things that can be done through web scraping. In the end, it is all about what you can do with the data that you have collected and made it valuable.