WWW::RobotRules(3)					User Contributed Perl Documentation					WWW::RobotRules(3)

NAME

       WWW::RobotsRules - Parse robots.txt files

SYNOPSIS

	require WWW::RobotRules;
	my $robotsrules = new WWW::RobotRules 'MOMspider/1.0';

	use LWP::Simple qw(get);

	$url = "http://some.place/robots.txt";
	my $robots_txt = get $url;
	$robotsrules->parse($url, $robots_txt);

	$url = "http://some.other.place/robots.txt";
	my $robots_txt = get $url;
	$robotsrules->parse($url, $robots_txt);

	# Now we are able to check if a URL is valid for those servers that
	# we have obtained and parsed "robots.txt" files for.
	if($robotsrules->allowed($url)) {
	    $c = get $url;
	    ...
	}

DESCRIPTION

       This module parses a /robots.txt file as specified in "A Standard for Robot Exclusion", described in
       <http://info.webcrawler.com/mak/projects/robots/norobots.html> Webmasters can use the /robots.txt file to disallow conforming robots access
       to parts of their web site.

       The parsed file is kept in the WWW::RobotRules object, and this object provides methods to check if access to a given URL is prohibited.
       The same WWW::RobotRules object can parse multiple /robots.txt files.

       The following methods are provided:

       $rules = WWW::RobotRules->new($robot_name)
	   This is the constructor for WWW::RobotRules objects.  The first argument given to new() is the name of the robot.

       $rules->parse($robot_txt_url, $content, $fresh_until)
	   The parse() method takes as arguments the URL that was used to retrieve the /robots.txt file, and the contents of the file.

       $rules->allowed($uri)
	   Returns TRUE if this robot is allowed to retrieve this URL.

       $rules->agent([$name])
	   Get/set the agent name. NOTE: Changing the agent name will clear the robots.txt rules and expire times out of the cache.

ROBOTS.TXT
       The format and semantics of the "/robots.txt" file are as follows (this is an edited abstract of
       <http://info.webcrawler.com/mak/projects/robots/norobots.html>):

       The file consists of one or more records separated by one or more blank lines. Each record contains lines of the form

	 <field-name>: <value>

       The field name is case insensitive.  Text after the '#' character on a line is ignored during parsing.  This is used for comments.  The
       following <field-names> can be used:

       User-Agent
	  The value of this field is the name of the robot the record is describing access policy for.	If more than one User-Agent field is
	  present the record describes an identical access policy for more than one robot. At least one field needs to be present per record.  If
	  the value is '*', the record describes the default access policy for any robot that has not not matched any of the other records.

       Disallow
	  The value of this field specifies a partial URL that is not to be visited. This can be a full path, or a partial path; any URL that
	  starts with this value will not be retrieved

ROBOTS.TXT EXAMPLES
       The following example "/robots.txt" file specifies that no robots should visit any URL starting with "/cyberworld/map/" or "/tmp/":

	 User-agent: *
	 Disallow: /cyberworld/map/ # This is an infinite virtual URL space
	 Disallow: /tmp/ # these will soon disappear

       This example "/robots.txt" file specifies that no robots should visit any URL starting with "/cyberworld/map/", except the robot called
       "cybermapper":

	 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: /

SEE ALSO

       LWP::RobotUA, WWW::RobotRules::AnyDBM_File

libwww-perl-5.65						    2001-04-20							WWW::RobotRules(3)