Have you ever wondered how a search engine is able to find the right links for you when you are searching of some information? A web spider forms the basic foundation of a search engine. It is a program which crawls the net in a particular manner for some specific purpose. Find out how…
The job of a web spider can be to gather information or to report about the structure and validity of various websites. Web spiders, also referred to as crawlers, extract data from the internet and pass it to other applications associated with each search engine, which indexes the contents of websites and displays the search results.
Let’s have a look at the workings of a search engine web spider. It is the web spider you should thank when you get the desired result after you type some keywords in the search box. A search engine makes use of many web spiders to crawl numerous pages available on the internet, to find the content related to your search and indexes the relevant links.
The rank of a website depends largely upon the site’s content and the number of pages which link to it.
However, even with the help of web crawlers, searching the internet is a challenge. If you want to know how big a challenge it is to find the appropriate content for the user, the fact that Google indexes more than 8 billion pages should suffice. Web spiders also follow a ‘politeness policy’, which gives the right to the web server to control which content can be crawled and which not.
Apart from search engine web spiders; there also exist corporate web crawlers.
The corporate web spiders list links and content which are not available openly to general public. These spiders do not work in a large scale environment and are restricted to a local network. Since the search of these web spiders is constrained, hence they deliver with better efficiency.
Google has taken an initiative to bring such spiders closer to the public by offering a search engine which can index the content of a work station or a personal computer.
Some non conventional uses of spiders are making content archives and generating statistics. An archiving web spider is used to extract all useful content from a website and store it locally for long-term. This can thus serve as an overview of the content and at the same time act as back-up.
Web spiders can generate interesting statistics like the number of web servers running at a given time, the number of web pages available, and the number of broken links.
Another specialised form of web spider is the web site checker. It crawls through the site for missing content, broken links, and validity of HTML in your design.
Web spiders thus serve a lot of purposes on the net and come to your aid when you are in search of some information. Web spiders have truly revolutionised the searching process on the internet.