What Is a Data Crawler?
A data crawler,mostly called a web crawler, as well as a spider, is an Internet bot that systematically browses the World Wide Web, typically for creating a search engine indices. Companies like Google or Facebook use web crawling to collect the data all the time.
How Does a Data Crawler work?
A crawler starts with a list of URLs to visit, and it will follow every hyperlink it can find on each page and add them to the list of URLs to visit. Web Data Crawlers are mainly used to create a copy of all the visited pages for later processing by a search engine, which will then index the downloaded pages so as to provide fast searches.
The web crawling procedure comprises of three steps. Firstly, the spider starts by crawling certain pages of a website. Next, it keeps indexing the words and content of the website, and lastly, it visits all the hyperlinks that are found in the site.
Date Crawler or Data Scraper?
We can say a crawler collects data thoroughly as everything on the web will eventually be found and spidered if it keeps visiting pages; however, it is also really time-consuming as it needs to go through all the links and it will drive you crazy when you have to recrawl every page to get new information
When it comes to crawling, what springs to mind is getting all kinds of data from the web. It collects all the URLs, even those that contain data you do not need. But true crawling actually refers to a very specific method of getting URLs, especially useful for indexing or SEO.
That is why we need another tool, data scraper (web scraper), which is highly targeted and super fast. You can build a web scraper to a specific website and then extract certain kind of data on that page. It is like a crawler guided by certain logic to extract data (not just URLs but any kind of data such as title) from the pages you want, making the whole extraction process much more efficient.
Why Data Crawler With Octoparse
Octoparse is a precise tool for the web scraping purpose. Not only does it save the amount of time for downloading the exact set of data that you want, but it also intelligently exports data into a structured format such as a spreadsheet or database.