The Robot Exclusion Standard, also known as the Robots Exclusion Protocol or robots.txt protocol, is a convention to prevent cooperating web spiders A Web crawler is a computer program that browses the World Wide Web in a methodical, automated manner. Other terms for Web crawlers are ants, automatic indexers, bots, and worms or Web spider, Web robot, or—especially in the FOAF community—Web scutter and other web robots Internet bots, also known as web robots, WWW robots or simply bots, are software applications that run automated tasks over the Internet. Typically, bots perform tasks that are both simple and structurally repetitive, at a much higher rate than would be possible for a human alone. The largest use of bots is in web spidering, in which an automated from accessing all or part of a website A website is a collection of related web pages, images, videos or other digital assets that are addressed relative to a common Uniform Resource Locator (URL), often consisting of only the domain name, or the IP address, and the root path ('/') in an Internet Protocol-based network. A web site is hosted on at least one web server, accessible via a which is otherwise publicly viewable. Robots are often used by search engines A web search engine is designed to search for information on the World Wide Web. The search results are generally presented in a list of results and are often called hits. The information may consist of web pages, images, information and other types of files. Some search engines also mine data available in databases or open directories. Unlike Web to categorize and archive web sites, or by webmasters to proofread source code. The standard is unrelated to, but can be used in conjunction with, Sitemaps The Sitemaps protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. A Sitemap is an XML file that lists the URLs for a site. It allows webmasters to include additional information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs, a robot inclusion standard for websites.

Contents

History

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The invention of "robots.txt" is attributed to Martijn Koster, when working for WebCrawler WebCrawler is a metasearch engine that blends the top search results from Google, Yahoo!, Bing Search , Ask.com, About.com, MIVA, LookSmart and other popular search engines. WebCrawler also provides users the option to search for images, audio, video, news, yellow pages and white pages. WebCrawler is a registered trademark of InfoSpace, Inc around 1994. "robots.txt" was then popularized with the advent of AltaVista AltaVista is a web search engine owned by Yahoo!. AltaVista was once one of the most popular search engines but its popularity waned with the rise of Google, and other popular search engines, in the following years.

About the standard

If a site owner wishes to give instructions to web robots he must place a text file called robots.txt in the root of the web site hierarchy (e.g. www.example.com/robots.txt). This text file should contain the instructions in a specific format (see examples below). Robots that choose to follow the instructions try to fetch this file and read the instructions before fetching any other file from the web site. If this file doesn't exist web robots assume that the web owner wishes to provide no specific instructions.

A robots.txt file on a website will function as a request that specified robots ignore specified files or directories in their search. This might be, for example, out of a preference for privacy from search engine results, or the belief that the content of the selected directories might be misleading or irrelevant to the categorization of the site as a whole, or out of a desire that an application only operate on certain data.

For websites with multiple subdomains, each subdomain must have its own robots.txt file. If example.com had a robots.txt file but a.example.com did not, the rules that would apply for example.com would not apply to a.example.com.

Disadvantages

The protocol is purely advisory. It relies on the cooperation of the web robot Internet bots, also known as web robots, WWW robots or simply bots, are software applications that run automated tasks over the Internet. Typically, bots perform tasks that are both simple and structurally repetitive, at a much higher rate than would be possible for a human alone. The largest use of bots is in web spidering, in which an automated, so that marking an area of a site out of bounds with robots.txt does not guarantee privacy. Some web site administrators have tried to use the robots file to make private parts of a website invisible to the rest of the world, but the file is necessarily publicly available and its content is easily checked by anyone with a web browser A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content. Hyperlinks present in resources enable users to easily navigate their browsers to.

There is no official standards body or RFC In computer network engineering, a Request for Comments is a memorandum published by the Internet Engineering Task Force (IETF) describing methods, behaviors, research, or innovations applicable to the working of the Internet and Internet-connected systems for the robots.txt protocol. It was created by consensus in June 1994 by members of the robots mailing list (robots-request@nexor.co.uk). The information specifying the parts that should not be accessed is specified in a file called robots.txt in the top-level directory of the website. The robots.txt patterns are matched by simple substring comparisons, so care should be taken to make sure that patterns matching directories have the final '/' character appended, otherwise all files with names starting with that substring will match, rather than just those in the directory intended.

Automated Content Access Protocol

Main article: Automated Content Access Protocol Automated Content Access Protocol is a proposed method of providing machine-readable permissions information for content. This will allow automated processes (such as search-engine web crawling) to be compliant with publishers' policies without the need for human interpretation of legal terms. ACAP was developed by organisations that represent

ACAP, which is a possible plug-in In computing, a plug-in is a small software computer program that extends the capabilities of a larger program. Plugins are commonly used in web browsers to enable them to play sounds and video clips, or automatically decompressing files. Add-on is often considered the general term comprising plug-ins, extensions, and themes as subcategories for the Robots Exclusion Standard, was released as v1.0 on November 30, 2006.

Examples

This example allows all robots to visit all files because the wildcard "*" specifies all robots:

User-agent: *
Disallow:

This example keeps all robots out:

User-agent: *
Disallow: /

The next is an example that tells all crawlers not to enter four directories of a website:

User-agent: *
Disallow: /cgi-bin/
Disallow: /images/
Disallow: /tmp/
Disallow: /private/

Example that tells a specific crawler not to enter one specific directory:

User-agent: BadBot # replace the 'BadBot' with the actual user-agent of the bot
Disallow: /private/

Example that tells all crawlers not to enter one specific file:

User-agent: *
Disallow: /directory/file.html

Note that all other files in the specified directory will be processed.

Example demonstrating how comments can be used:

# Comments appear after the "#" symbol at the start of a line, or after a directive
User-agent: * # match all bots
Disallow: / # keep them out

Nonstandard extensions

Crawl-delay directive

Several major crawlers support a Crawl-delay parameter, set to the number of seconds to wait between successive requests to the same server:[1][2][3]

User-agent: *
Crawl-delay: 10

Allow directive

Some major crawlers support an Allow directive which can counteract a following Disallow directive.[4] [5] This is useful when one disallows an entire directory but still wants some HTML documents in that directory crawled and indexed. While by standard implementation the first matching robots.txt pattern always wins, Google's implementation differs in that it first evaluates all Allow patterns and only then all Disallow patterns. Bing uses the Allow or Disallow directive which is the most specific.[6]

In order to be compatible to all robots, if one wants to allow single files inside an otherwise disallowed directory, it is necessary to place the Allow directive(s) first, followed by the Disallow, for example:

Allow: /folder1/myfile.html
Disallow: /folder1/

This example will Disallow anything in /folder1/ except /folder1/myfile.html, since the latter will match first. In case of Google, though, the order is not important.

Sitemap

Some crawlers support a Sitemap directive, allowing multiple Sitemaps The Sitemaps protocol allows a webmaster to inform search engines about URLs on a website that are available for crawling. A Sitemap is an XML file that lists the URLs for a site. It allows webmasters to include additional information about each URL: when it was last updated, how often it changes, and how important it is in relation to other URLs in the same robots.txt in the form:[7]

Sitemap: http://www.gstatic.com/s2/sitemaps/profiles-sitemap.xml
Sitemap: http://www.google.com/hostednews/sitemap_index.xml

Extended standard

An Extended Standard for Robot Exclusion has been proposed, which adds several new directives, such as Visit-time and Request-rate. For example:

User-agent: *
Disallow: /downloads/
Request-rate: 1/5 # maximum rate is one page every 5 seconds
Visit-time: 0600-0845 # only visit between 06:00 and 08:45 UTC (GMT)

The first version of the Robot Exclusion standard does not mention anything about the "*" character in the Disallow: statement. Some crawlers like Googlebot and Slurp recognize strings containing "*", while MSNbot and Teoma interpret it in different ways.[8]

See also

References

  1. ^ "How can I reduce the number of requests you make on my web site?". Yahoo! Slurp. http://help.yahoo.com/l/us/yahoo/search/webcrawler/slurp-03.html. Retrieved 2007-03-31.
  2. ^ "MSNBot is crawling a site too frequently". Troubleshoot issues with MSNBot and site crawling. http://search.msn.com/docs/siteowner.aspx?t=SEARCH_WEBMASTER_FAQ_MSNBotIndexing.htm&FORM=WFDD#D. Retrieved 2007-02-08.
  3. ^ "About Ask.com: Webmasters". http://about.ask.com/en/docs/about/webmasters.shtml#15.
  4. ^ "Webmaster Help Center - How do I block Googlebot?". http://www.google.com/support/webmasters/bin/answer.py?answer=40364. Retrieved 2007-11-20.
  5. ^ "How do I prevent my site or certain subdirectories from being crawled? - Yahoo Search Help". http://help.yahoo.com/l/us/yahoo/search/webcrawler/slurp-02.html. Retrieved 2007-11-20.
  6. ^ "Robots Exclusion Protocol - joining together to provide better documentation". http://www.bing.com/community/blogs/webmaster/archive/2008/06/03/robots-exclusion-protocol-joining-together-to-provide-better-documentation.aspx. Retrieved 2009-12-03.
  7. ^ "Yahoo! Search Blog - Webmasters can now auto-discover with Sitemaps". http://ysearchblog.com/2007/04/11/webmasters-can-now-auto-discover-with-sitemaps/. Retrieved 2009-03-23.
  8. ^ "Search engines and dynamic content issues". MSNbot issues with robots.txt. http://www.serbanghita.com/search-engines-dynamic-content-issues.html. Retrieved 2007-04-01.

External links

Search engine optimization Search engine optimization is the process of improving the visibility of a web site or a web page in search engines via the "natural" or un-paid ("organic" or "algorithmic") search results. Other forms of search engine marketing (SEM) target paid listings. In general, the earlier (or higher on the page), and more
Exclusion standards Robots exclusion standard • Meta tags Meta elements are HTML or XHTML elements used to provide structured metadata about a Web page. Such elements must be placed as tags in the< code>head section of an HTML or XHTML document. Meta elements can be used to specify page description, keywords and any other metadata not provided through the other head elements and attributes • nofollow nofollow is an HTML attribute value used to instruct some search engines that a hyperlink should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring
Related marketing topics Internet marketing Internet marketing, also referred to as i-marketing, web-marketing, online-marketing or e-Marketing, is the marketing of products or services over the Internet • E-mail marketing E-mail marketing is a form of direct marketing which uses electronic mail as a means of communicating commercial or fundraising messages to an audience. In its broadest sense, every e-mail sent to a potential or current customer could be considered e-mail marketing. However, the term is usually used to refer to: • Display advertising • Web analytics Web analytics is the measurement, collection, analysis and reporting of internet data for purposes of understanding and optimizing web usage
Search marketing related topics Search engine marketing Search engine marketing, or SEM, is a form of Internet marketing that seeks to promote websites by increasing their visibility in search engine result pages through the use of search engine optimization, paid placement, contextual advertising, and paid inclusion.. Usage of the term "search engine marketing" has been inconsistent. The • Social media optimization Social media optimization Social Media Optimization is the methodization of social media activity with the intent of attracting unique visitors to website content. SMO is one of two online methods of website optimization; the other method is search engine optimization or SEO • Online identity management Online identity management also known as online image management or online personal branding or personal reputation management (PRM) is a set of methods for generating a distinguished Web presence of a person on the Internet. That presence could be reflected in any kind of content that refers to the person, including news, participation in blogs • Paid inclusion Paid inclusion is a search engine marketing product where the search engine company charges fees related to inclusion of websites in their search index. Paid inclusion products are provided by most search engine companies, the most notable exception being Google • Pay per click (PPC) Pay Per Click is an Internet advertising model used on websites, in which advertisers pay their host only when their ad is clicked. With search engines, advertisers typically bid on keyword phrases relevant to their target market. Content sites commonly charge a fixed price per click rather than use a bidding system • Google bomb The terms Google bomb and Googlewashing refer to practices intended to influence the ranking of particular pages in results returned by the Google search engine, in order to increase the likelihood of people finding and clicking on selections in which the individual or other entity engaging in this practice is interested. It is done for either
Search engine spam Spamdexing Spamdexing involves a number of methods, such as repeating unrelated phrases, to manipulate the relevancy or prominence of resources indexed by a search engine, in a manner inconsistent with the purpose of the indexing system. Some consider it to be a part of search engine optimization, though there are many search engine optimization methods that • Web scraping Web scraping is a computer software technique of extracting information from websites. Usually, such software programs simulate human exploration of the Web by either implementing low-level Hypertext Transfer Protocol (HTTP), or embedding certain full-fledged Web browsers, such as the Internet Explorer (IE) and the Mozilla Web browser. Web • Scraper site A scraper site is a website that copies all of its content from other websites using web scraping. A search engine is not a scraper site:[citation needed] sites such as Yahoo and Google gather content from other websites and index it so that the index can be searched with keywords. Search engines then display snippets of the original site content • Link farm On the World Wide Web, a link farm is any group of web sites that all hyperlink to every other site in the group. Although some link farms can be created by hand, most are created through automated programs and services. A link farm is a form of spamming the index of a search engine . Other link exchange systems are designed to allow individual • Free for all linking This article pertains to methods of hyperlinking to/of different websites, often used in regard to search engine optimization
Linking Methods of website linking This article pertains to methods of hyperlinking to/of different websites, often used in regard to search engine optimization • Link exchange A link exchange is a confederation of websites that operates similarly to a web ring. Webmasters register their web sites with a central organization, that runs the exchange, and in turn receive from the exchange HTML code which they insert into their web pages. In contrast to a web ring, where the HTML code simply comprises simple circular ring • Backlink Backlinks are incoming links to a website or web page. Inbound links were originally important as a primary means of web navigation; today their significance lies in search engine optimization (SEO). The number of backlinks is one indication of the popularity or importance of that website or page (though other measures, such as PageRank, are also
Other IP delivery Geo targeting in geomarketing and internet marketing is the method of determining the geolocation of a website visitor and delivering different content to that visitor based on his or her location, such as country, region/state, city, metro code/zip code, organization, IP address, ISP or other criteria. A common usage of geo targeting is found in • Human search engine A human search engine is a search engine that uses human participation to filter the search results and assist users in clarifying their search request. The goal is to provide users with a limited number of relevant results, as opposed to traditional search engines that often return a large number of results that may or may not be relevant • Stop words Stop words is the name given to words which are filtered out prior to, or after, processing of natural language data . Hans Peter Luhn, one of the pioneers in information retrieval, is credited with coining the phrase and using the concept in his design. It is controlled by human input and not automated. This is sometimes seen as a negative • Poison words • Content farm

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Search Engine Roundtable (blog) It should look something like: Microsoft said that BingBot will continue to respect and honor the msnbot directives in the robots.txt file, ...
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RewriteEngine on RewriteCond $1 !^(index\.php|p​ublic|images|. robots\.txt. ) RewriteRule ^(.*)$ /index.php/$1 [L]. Once you have all the files in place, you can start creating your controller and view. Controller: charts.php ...

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how many robots.txt files do i need in my site?
Q. do in to put the file in every level of my site or just in the root directory? basically do i need more than 1 robots.txt files on my site?
Asked by abc - Sat Mar 28 11:48:38 2009 - - 2 Answers - 0 Comments

A. Where to put it The short answer: in the top-level directory of your web server. The longer answer: When a robot looks for the "/robots.txt" file for URL, it strips the path component from the URL (everything from the first single slash), and puts "/robots.txt" in its place. For example, for "http://www.example.com/s hop/index.html, it will remove the "/shop/index.html", and replace it with "/robots.txt", and will end up with "http://www.example.com/r obots.txt". So, as a web site owner you need to put it in the right place on your web server for that resulting URL to work. Usually that is the same place where you put your web site's main "index.html" welcome page. Where exactly that is, and how to put the file there, depends on… [cont.]
Answered by DeadlyFishy - Sat Mar 28 11:56:18 2009

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