Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
WWW::RobotRules(3)    User Contributed Perl Documentation   WWW::RobotRules(3)

       WWW::RobotRules - database of robots.txt-derived	permissions

	use WWW::RobotRules;
	my $rules = WWW::RobotRules->new('MOMspider/1.0');

	use LWP::Simple	qw(get);

	  my $url = "";
	  my $robots_txt = get $url;
	  $rules->parse($url, $robots_txt) if defined $robots_txt;

	  my $url = "";
	  my $robots_txt = get $url;
	  $rules->parse($url, $robots_txt) if defined $robots_txt;

	# Now we can check if a	URL is valid for those servers
	# whose	"robots.txt" files we've gotten	and parsed:
	if($rules->allowed($url)) {
	    $c = get $url;

       This module parses /robots.txt files as specified in "A Standard	for
       Robot Exclusion", at <>
       Webmasters can use the /robots.txt file to forbid conforming robots
       from accessing parts of their web site.

       The parsed files	are kept in a WWW::RobotRules object, and this object
       provides	methods	to check if access to a	given URL is prohibited.  The
       same WWW::RobotRules object can be used for one or more parsed
       /robots.txt files on any	number of hosts.

       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.

	   Returns TRUE	if this	robot is allowed to retrieve this URL.

	   Get/set the agent name. NOTE: Changing the agent name will clear
	   the robots.txt rules	and expire times out of	the cache.

       The format and semantics	of the "/robots.txt" file are as follows (this
       is an edited abstract of	<>):

       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:

	  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.

	  The User-Agent fields	must occur before the Disallow fields.	If a
	  record contains a User-Agent field after a Disallow field, that
	  constitutes a	malformed record.  This	parser will assume that	a
	  blank	line should have been placed before that User-Agent field, and
	  will break the record	into two.  All the fields before the User-
	  Agent	field will constitute a	record,	and the	User-Agent field will
	  be the first field in	a new record.

	  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

       Unrecognized records are	ignored.

       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

	 User-agent: *
	 Disallow: /cyberworld/map/ # This is an infinite virtual URL space

	 # Cybermapper knows where to go.
	 User-agent: cybermapper

       This example indicates that no robots should visit this site further:

	 # go away
	 User-agent: *
	 Disallow: /

       This is an example of a malformed robots.txt file.

	 # robots.txt for
	 # I've	locked myself away.
	 User-agent: *
	 Disallow: /
	 # The castle is your home now,	so you can go anywhere you like.
	 User-agent: Belle
	 Disallow: /west-wing/ # except	the west wing!
	 # It's	good to	be the Prince...
	 User-agent: Beast

       This file is missing the	required blank lines between records.
       However,	the intention is clear.

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

	 Copyright 1995-2009, Gisle Aas
	 Copyright 1995, Martijn Koster

       This library is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

perl v5.32.1			  2012-02-18		    WWW::RobotRules(3)


Want to link to this manual page? Use this URL:

home | help