A spider trap (or crawler trap) is a set of web pages that may intentionally or unintentionally be used to cause a web crawler or search bot to make an infinite number of requests or cause a poorly constructed crawler to crash. Web crawlers are also called web spiders, from which the name is derived. Spider traps may be created to "catch" spambots or other crawlers that waste a website's bandwidth. They may also be created unintentionally by calendars that use dynamic pages with links that continually point to the next day or year.
Common techniques used are:
http://example.com/bar/foo/bar/foo/bar/foo/bar/...
There is no algorithm to detect all spider traps. Some classes of traps can be detected automatically, but new, unrecognized traps arise quickly.
A spider trap causes a web crawler to enter something like an infinite loop, [3] which wastes the spider's resources, [4] lowers its productivity, and, in the case of a poorly written crawler, can crash the program. Polite spiders alternate requests between different hosts, and do not request documents from the same server more than once every several seconds, [5] meaning that a "polite" web crawler is affected to a much lesser degree than an "impolite" crawler.[ citation needed ]
In addition, sites with spider traps usually have a robots.txt telling bots not to go to the trap, so a legitimate "polite" bot would not fall into the trap, whereas an "impolite" bot which disregards the robots.txt settings would be affected by the trap. [6]
In general computing, a search engine is an information retrieval system designed to help find information stored on a computer system. It is an information retrieval software program that discovers, crawls, transforms, and stores information for retrieval and presentation in response to user queries. The search results are usually presented in a list and are commonly called hits. A search engine normally consists of four components, as follows: a search interface, a crawler, an indexer, and a database. The crawler traverses a document collection, deconstructs document text, and assigns surrogates for storage in the search engine index. Online search engines store images, link data and metadata for the document as well.
A 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.
robots.txt is the filename used for implementing the Robots Exclusion Protocol, a standard used by websites to indicate to visiting web crawlers and other web robots which portions of the website they are allowed to visit.
Search engine optimization (SEO) is the process of improving the quality and quantity of website traffic to a website or a web page from search engines. SEO targets unpaid traffic rather than direct traffic or paid traffic. Unpaid traffic may originate from different kinds of searches, including image search, video search, academic search, news search, and industry-specific vertical search engines.
Googlebot is the web crawler software used by Google that collects documents from the web to build a searchable index for the Google Search engine. Googlebot was created to function concurrently on thousands of machines in order to enhance its performance and adapt to the expanding size of the internet. This name is actually used to refer to two different types of web crawlers: a desktop crawler and a mobile crawler.
The deep web, invisible web, or hidden web are parts of the World Wide Web whose contents are not indexed by standard web search-engine programs. This is in contrast to the "surface web", which is accessible to anyone using the Internet. Computer scientist Michael K. Bergman is credited with inventing the term in 2001 as a search-indexing term.
In computing, the User-Agent header is an HTTP header intended to identify the user agent responsible for making a given HTTP request. Whereas the character sequence User-Agent
comprises the name of the header itself, the header value that a given user agent uses to identify itself is colloquially known as its user agent string. The user agent for the operator of a computer used to access the Web has encoded within the rules that govern its behavior the knowledge of how to negotiate its half of a request-response transaction; the user agent thus plays the role of the client in a client–server system. Often considered useful in networks is the ability to identify and distinguish the software facilitating a network session. For this reason, the User-Agent HTTP header exists to identify the client software to the responding server.
A spambot is a computer program designed to assist in the sending of spam. Spambots usually create accounts and send spam messages with them. Web hosts and website operators have responded by banning spammers, leading to an ongoing struggle between them and spammers in which spammers find new ways to evade the bans and anti-spam programs, and hosts counteract these methods.
An Internet bot, web robot, robot or simply bot, is a software application that runs automated tasks (scripts) on the Internet, usually with the intent to imitate human activity, such as messaging, on a large scale. An Internet bot plays the client role in a client–server model whereas the server role is usually played by web servers. Internet bots are able to perform simple and repetitive tasks much faster than a person could ever do. The most extensive use of bots is for web crawling, in which an automated script fetches, analyzes and files information from web servers. More than half of all web traffic is generated by bots.
Email harvesting or scraping is the process of obtaining lists of email addresses using various methods. Typically these are then used for bulk email or spam.
Web scraping, web harvesting, or web data extraction is data scraping used for extracting data from websites. Web scraping software may directly access the World Wide Web using the Hypertext Transfer Protocol or a web browser. While web scraping can be done manually by a software user, the term typically refers to automated processes implemented using a bot or web crawler. It is a form of copying in which specific data is gathered and copied from the web, typically into a central local database or spreadsheet, for later retrieval or analysis.
A search engine is a software system that finds web pages that match a web search. They search the World Wide Web in a systematic way for particular information specified in a textual web search query. The search results are generally presented in a line of results, often referred to as search engine results pages (SERPs). The information may be a mix of hyperlinks to web pages, images, videos, infographics, articles, and other types of files. Some search engines also mine data available in databases or open directories. Unlike web directories and social bookmarking sites, which are maintained by human editors, search engines also maintain real-time information by running an algorithm on a web crawler. Any internet-based content that cannot be indexed and searched by a web search engine falls under the category of deep web. Modern search engines are based on techniques and methods developed in the field of Information retrieval.
URI normalization is the process by which URIs are modified and standardized in a consistent manner. The goal of the normalization process is to transform a URI into a normalized URI so it is possible to determine if two syntactically different URIs may be equivalent.
Web archiving is the process of collecting portions of the World Wide Web to ensure the information is preserved in an archive for future researchers, historians, and the public. Web archivists typically employ web crawlers for automated capture due to the massive size and amount of information on the Web. The largest web archiving organization based on a bulk crawling approach is the Wayback Machine, which strives to maintain an archive of the entire Web.
Honeypots are security devices whose value lie in being probed and compromised. Traditional honeypots are servers that wait passively to be attacked. Client Honeypots are active security devices in search of malicious servers that attack clients. The client honeypot poses as a client and interacts with the server to examine whether an attack has occurred. Often the focus of client honeypots is on web browsers, but any client that interacts with servers can be part of a client honeypot.
A focused crawler is a web crawler that collects Web pages that satisfy some specific property, by carefully prioritizing the crawl frontier and managing the hyperlink exploration process. Some predicates may be based on simple, deterministic and surface properties. For example, a crawler's mission may be to crawl pages from only the .jp domain. Other predicates may be softer or comparative, e.g., "crawl pages about baseball", or "crawl pages with large PageRank". An important page property pertains to topics, leading to 'topical crawlers'. For example, a topical crawler may be deployed to collect pages about solar power, swine flu, or even more abstract concepts like controversy while minimizing resources spent fetching pages on other topics. Crawl frontier management may not be the only device used by focused crawlers; they may use a Web directory, a Web text index, backlinks, or any other Web artifact.
BotSeer was a Web-based information system and search tool used for research on Web robots and trends in Robot Exclusion Protocol deployment and adherence. It was created and designed by Yang Sun, Isaac G. Councill, Ziming Zhuang and C. Lee Giles. BotSeer was in operation from 2007 to 2010, approximately.
The Wayback Machine is a digital archive of the World Wide Web founded by the Internet Archive, a nonprofit based in San Francisco, California. Created in 1996 and launched to the public in 2001, it allows the user to go "back in time" to see how websites looked in the past. Its founders, Brewster Kahle and Bruce Gilliat, developed the Wayback Machine to provide "universal access to all knowledge" by preserving archived copies of defunct web pages.
Bingbot is a web-crawling robot, deployed by Microsoft October 2010 to supply Bing. It collects documents from the web to build a searchable index for the Bing. It performs the same as Google's Googlebot.
Yandex Search is a search engine. It is owned by Yandex, based in Russia. In January 2015, Yandex Search generated 51.2% of all of the search traffic in Russia according to LiveInternet.