|How To Prevent Webcrawlers From Indexing Your Website|
Exclusion Standard is the approved method used by website
administrators to control what web crawling robots will index on your
website. Below is a summary of that standard.
A Standard for Robot ExclusionTable of contents:
the Robots pages at WebCrawler for details], between the majority of robot authors and other people with an interest in robots. It has also been open for discussion on the Technical World Wide Web mailing list (email@example.com). This document is based on a previous working draft under the same title.
It is not an official standard backed by a standards body, or owned by any commercial organisation. It is not enforced by anybody, and there no guarantee that all current and future robots will use it. Consider it a common facility the majority of robot authors offer the WWW community to protect WWW server against unwanted accesses by their robots.
The latest version of this document can be found on http://www.robotstxt.org/wc/robots.html.
the robots page.
In 1993 and 1994 there have been occasions where robots have visited WWW servers where they weren't welcome for various reasons. Sometimes these reasons were robot specific, e.g. certain robots swamped servers with rapid-fire requests, or retrieved the same files repeatedly. In other situations robots traversed parts of WWW servers that weren't suitable, e.g. very deep virtual trees, duplicated information, temporary information, or cgi-scripts with side-effects (such as voting).
These incidents indicated the need for established mechanisms for WWW servers to indicate to robots which parts of their server should not be accessed. This standard addresses this need with an operational solution.
This approach was chosen because it can be easily implemented on any existing WWW server, and a robot can find the access policy with only a single document retrieval.
A possible drawback of this single-file approach is that only a server administrator can maintain such a list, not the individual document maintainers on the server. This can be resolved by a local process to construct the single file from a number of others, but if, or how, this is done is outside of the scope of this document.
The choice of the URL was motivated by several criteria:
The file consists of one or more records separated by one or more blank
lines (terminated by CR,CR/NL, or NL). Each record contains lines of the
Comments can be included in file using UNIX bourne shell conventions:
The record starts with one or more
# robots.txt for http://www.example.com/ User-agent: * Disallow: /cyberworld/map/ # This is an infinite virtual URL space Disallow: /tmp/ # these will soon disappear Disallow: /foo.html
This example "
# robots.txt for http://www.example.com/ User-agent: * Disallow: /cyberworld/map/ # This is an infinite virtual URL space # Cybermapper knows where to go. User-agent: cybermapper Disallow:
This example indicates that no robots should visit this site further:
# go away User-agent: * Disallow: /
Note: This code is no longer available. Instead I recommend using the robots exclusion code in the Perl libwww-perl5 library, available from CPAN in the LWP directory.
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|Last revision: December 30, 2006 05:59 PM|
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