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Web Crawler
Web crawler, sometimes called a spider or spiderbot and often shortened to crawler, is an Internet bot that systematically browses the World Wide Web and that is typically operated by search engines for the purpose of Web indexing (''web spidering''). Web search engines and some other websites use Web crawling or spidering software to update their web content or indices of other sites' web content. Web crawlers copy pages for processing by a search engine, which Index (search engine), indexes the downloaded pages so that users can search more efficiently. Crawlers consume resources on visited systems and often visit sites unprompted. Issues of schedule, load, and "politeness" come into play when large collections of pages are accessed. Mechanisms exist for public sites not wishing to be crawled to make this known to the crawling agent. For example, including a robots.txt file can request Software agent, bots to index only parts of a website, or nothing at all. The number of In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Uniform Resource Locator
A uniform resource locator (URL), colloquially known as an address on the World Wide Web, Web, is a reference to a web resource, resource that specifies its location on a computer network and a mechanism for retrieving it. A URL is a specific type of Uniform Resource Identifier (URI), although many people use the two terms interchangeably. URLs occur most commonly to reference web pages (Hypertext Transfer Protocol, HTTP/HTTPS) but are also used for file transfer (File Transfer Protocol, FTP), email (mailto), database access (Java Database Connectivity, JDBC), and many other applications. Most web browsers display the URL of a web page above the page in an address bar. A typical URL could have the form http://www.example.com/index.html, which indicates a protocol (http), a hostname (www.example.com), and a file name (index.html). History Uniform Resource Locators were defined in in 1994 by Tim Berners-Lee, the inventor of the World Wide Web, and the URI working group of the In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
