It is almost close to three decades since the advent of web crawlers which was incepted in the early nineties. It has been quite a long time since web crawlers have been assisting in cutting out the chaos only to streamline data like extracting music out of noise. While, in its early days, the role of web crawlers was restricted to fetching and storing webpage statistics, with time, even these virtual bots have evolved. Today, these web crawlers are capable of not only fetching any kind of data even out of the most complex web pages and applications, but also to text the vulnerability of these web pages and applications.
Today, one can choose a web crawler from a variety of available ones. Choose? Yes. Web crawlers are available in various degrees of utility and value addition capabilities – you can always choose the one that suits you and fits your needs best.
Web crawling is simply the process of letting an algorithm-driven program bot to explore and parse through the trillion-ton ocean of data to fetch all relevant data-points and store it in a ready to consume format. The typical objective of a web crawler is to discover web pages of an online application. In most cases, this is done by recreating the combinations of user behavior to interact with the interface. With the rapid development and swelling of data floating over the world wide web, people today are even more dependent on search engines to seek information. Interestingly, launching a bot each time a search is triggered by a user is a highly inefficient and time-consuming process. So, what to the biggest search engines do? What does google do?
First, try imagining a world without google’s search engine. Okay, any search engine (ask and bing if that catches your fancy). The very though makes our mind go numb, right? If it weren’t for search engines, how would we even be able to find the relevant content that we are looking for? Web crawlers play a crucial role in search engines. Though many assume search engines and web crawlers to be the same thing, it definitely is not.
So, let’s break this down and understand what actually happens behind that plain white webpage with nothing but a fancy doodle and a search bar right in the middle of the page.
Whenever you try to fetch information pertaining to a particular data point, google does not launch a web crawler to search for it. Then how does it fetch all the relevant data, then? Simple, it has already crawled, sorted, and stored all of the internet even before you entered your search. Think of google as the baker who does not make you wait till it bakes the bread you want, instead it has already prepared and marked all possible kinds of bread that you may want.
So, as we already know that the world wide web is flooded with so much data, then how does google even manage to crawl millions of webpages with almost over a trillion zillion gigabytes of data to find you exactly the information you were hunting for?
Simple, google starts of small with a small list of known URLs and begins crawling them. Subsequently, one page leads to another and more URLs are discovered and explored. Hence, google uses a highly sophisticated extrapolative technology to deliver information to you just as you need it.