Various Open Source Tools Used for Web Crawling Services

A web crawler is also known as a web spider or web robot. It is a program or automated script which is used to browse the World Wide Web in a methodical and automated manner. The process is known as web crawling. Web crawling services are generally hired to create a copy of all the visited pages for future processing by a search engine that will create a file of the downloaded pages to provide fast searches. Crawlers’ automatically maintain tasks on a website such as testing links or validating HTML code. Crawlers are generally used to collect specific kind of information from the web pages such as harvesting e-mail addresses (usually for spam).

There are several uses for web crawlers, but basically, a web crawler is used to collect or mine data from the web. We use various open source web crawlers for delivering the result-based web crawling services.

Heritrix - It is the Internet Archive's open-source, web-scale, extensible, archival quality web crawler project.  As our crawler hunt for collecting and preserving the digital data for the benefit of upcoming researchers and generations, this source seemed appropriate.

Scrapy - An open source and shared framework for mining the data required from websites in a fast, simple, yet extensible way. We build and run web spiders and deploy them to a scrapy cloud.

DataPark Search – This open source has features like

• Supporting HTTP, HTTPs, NNTP, FTP, and new URL schemes
• HTDB virtual based URL scheme for indexing SQL databases
• Indexes text/XML, text/plain, text/HTML, audio/MPEG, and image/GIF mime types natively

HTTrack - It allows downloading a website from the Internet to a local directory, getting HTML, images, building recursively all directories, and other files from the server to the computer. HTTrack gathers the original site's relative link-structure by simply opening a page of the "mirrored" website in the browser, and then you can browse the website from link to link as if it was viewing online.

PHPCrawl – It is a framework for crawling websites that are written in the PHP programming language. Thus it can be called as web crawler engine for PHP.