Last Updated on April 17, 2022 by Journal Fact
If you’ve been reading on how to pull data from online resources and use it to fuel your decisions, you’ve probably crossed paths with a web crawler. Web crawlers are as old as the internet is. Understanding what a web crawler is can help you understand how it can help you and decide whether to use it.
However, information about web crawlers is hard to come by. Fortunately, you’ve found a perfect source to read through. Below you can find all about a web crawler, including what it is and what are the challenges of crawling.
A web crawler is just one name for a program able to go through a website and index and download all or specific content from it. It is also called a bot or search engine bot. Some people like to refer to it as a spider or simply a crawler. It was named after its ability to automatically access a website and obtain data that it holds.
Why would such a program exist? Well, that’s how search engines work. Each one of them has an internally developed crawler that works 24/7/365. Thanks to the crawlers, we can seamlessly search the web. The other use case is web scraping in the business world. Businesses use it to get hold of data and gain a competitive advantage or fail-proof decision-making process.
The crawlers that we have today are nothing like the first web crawlers ever. Visit this website to find out what is a web crawler. Now let’s see which crawlers were first used online.
While there are thousands of different crawlers today, back in the day, there were only 3.
RBSE spider was developed by NASA back in 1994 when there were only 1000,000 web pages online. The developers at the University of Houston, Clear Lake, worked on the Repository Base Software Engineering program and created one of the first crawlers. It was written in C, wais, and Oracle. RBSE was built to index data which will serve as a source for statistics.
For more information please visit: web scraping project
WebCrawler was created by just one man. Brian Pinkerton, who was at that moment at the University of Washington, created WebCrawler and launched it in 1994. At the time, it was the only search engine online which was based on a web crawler.
Archive.org is also known as Internet Archive and Wayback Machine. Its main project was to archive the entirety of the web. The name of the web crawler in charge was Heritrix. The crawler was written in Java. The creators ensured that it remained free and accessible to anyone who wanted to use it. Internet Archive gave all the data Heritrix pulled to Alexa, a company that also specializes in web crawling.
The value of data scraping and crawling returned is immense. Soon enough, businesses across industries have picked up on it. However, at the start, only organizations big enough to sustain dedicated teams of developers on the payroll used web crawlers and scrapers. After some time, it became increasingly hard to manage crawling projects at scale.
The next phase in the evolution of web crawlers is “Do it Yourself” or DIY. There were a couple of really good DIY crawlers, such as Scrapy and Apache Nutch. However, as the web structures became more complex and using dynamic web elements became more popular, web crawlers became less efficient.
The answer came from the companies specializing in building custom web crawling and scraping solutions. All the businesses that still saw value in data decided to partner with these companies. As a matter of fact, they still do. One might say that the current stage in the evolution of web crawling is the outsourcing model.
The evolution of web crawling is far from over . There are still some challenges that crawlers have to overcome to crawl through 100% of web pages out there. On the top of the list, we have anti-crawling and anti-scraping measures. They are designed to detect crawlers and ban them from accessing the site.
Then we have non-uniform web structures and AJAX elements which make crawling borderline impossible. Web crawling doesn’t come without risks, such as the risk of doing DDoS on the server where the target website is hosted. The problem with latency in operations at scale is also present.
As you can see, it’s not that hard to understand what a web crawler is. The crawlers have been with us since 1994. Over time it evolved into these sophisticated bots able to pass as human users while crawling through website structure and pulling the data. Some challenges such as anti-crawling measures, latency, and non-uniform web structures still remain.