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Web Crawler
(Posted on 2007/09/05, 18:38:26)

A web crawler (also known as a Web spider or Web robot) is a program or automated script which browses the World Wide Web in a methodical, automated manner. Other less frequently used names for Web crawlers are ants, automatic indexers, bots, and worms (Kobayashi and Takeda, 2000).

This process is called Web crawling or spidering. Many sites, in particular search engines, use spidering as a means of providing up-to-date data. Web crawlers are mainly used to create a copy of all the visited pages for later processing by a search engine that will index the downloaded pages to provide fast searches. Crawlers can also be used for automating maintenance tasks on a Web site, such as checking links or validating HTML code. Also, crawlers can be used to gather specific types of information from Web pages, such as harvesting e-mail addresses (usually for spam).

A Web crawler is one type of bot, or software agent. In general, it starts with a list of URLs to visit, called the seeds. As the crawler visits these URLs, it identifies all the hyperlinks in the page and adds them to the list of URLs to visit, called the crawl frontier. URLs from the frontier are recursively visited according to a set of policies.



web spider, web, web crawler


Posted on 2011/06/01, 17:11:01
" dost daram 0zv sham "
Posted on 2008/05/13, 09:43:28
" arachnode.net is a site crawler written in C# using SQL 2005. "
Posted on 2007/12/31, 14:07:27
" salam Mr Syavash man Nazanin Ahmady hastam Software khandam dar jost o jooye interneteeyam baraye hale moshkeli kari be ite shoma bar khord kadam fekr kardam shayad betavanam az shoma komak begeeram ma moshkelam ra minevisam agar javabbedaheed mamnoon meehavam source crawler i ba C# be dastam reseede ke mikhaham dar an tagheeratee bedaham avvaln meekhaham ke har 10 seconds yek bar kkar konad saneeyan etelaateee ra ke meegeerad dar database e ke man be oo moarefi mikonam berizad salesan cpu usage an ra ke kheily balast paeen beeyavaram. mamnoon Nazanin "
Posted on 2007/10/25, 06:59:59
" salam vaght be khir man ye soal dashtam dar mored chegongei tarahi ya barnameh nevisi web spider , crawler khoshal misham rahnmaiam konid mamnon "