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

NAME
       WWW::RobotRules - database of robots.txt-derived permissions
SYNOPSIS
        use WWW::RobotRules;
        my $rules = WWW::RobotRules->new('MOMspider/1.0');
        use LWP::Simple qw(get);
        {
          my $url = "http://some.place/robots.txt";
          my $robots_txt = get $url;
          $rules->parse($url, $robots_txt) if defined $robots_txt;
        }
        {
          my $url = "http://some.other.place/robots.txt";
          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;
            ...
        }
DESCRIPTION
       This module parses /robots.txt files as specified in "A Standard for
       Robot Exclusion", at <http://www.robotstxt.org/wc/norobots.html>;
       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.
       $rules->allowed($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://www.robotstxt.org/wc/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.
          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.
       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
       Unrecognized records are ignored.
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: /
       This is an example of a malformed robots.txt file.
         # robots.txt for ancientcastle.example.com
         # 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
         Disallow:
       This file is missing the required blank lines between records.
       However, the intention is clear.
SEE ALSO
       LWP::RobotUA, WWW::RobotRules::AnyDBM_File
COPYRIGHT
         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 v5.16.3                      2012-02-18                WWW::RobotRules(3)