WWW::RobotRules(3pm)

1WWW::RobotRules(3)    User Contributed Perl Documentation   WWW::RobotRules(3)
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NAME

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

9        use WWW::RobotRules;
10        my $rules = WWW::RobotRules->new('MOMspider/1.0');
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12        use LWP::Simple qw(get);
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14        {
15          my $url = "http://some.place/robots.txt";
16          my $robots_txt = get $url;
17          $rules->parse($url, $robots_txt) if defined $robots_txt;
18        }
19
20        {
21          my $url = "http://some.other.place/robots.txt";
22          my $robots_txt = get $url;
23          $rules->parse($url, $robots_txt) if defined $robots_txt;
24        }
25
26        # Now we can check if a URL is valid for those servers
27        # whose "robots.txt" files we've gotten and parsed:
28        if($rules->allowed($url)) {
29            $c = get $url;
30            ...
31        }
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DESCRIPTION

34       This module parses /robots.txt files as specified in "A Standard for
35       Robot Exclusion", at <http://www.robotstxt.org/wc/norobots.html> Web‐
36       masters can use the /robots.txt file to forbid conforming robots from
37       accessing parts of their web site.
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39       The parsed files are kept in a WWW::RobotRules object, and this object
40       provides methods to check if access to a given URL is prohibited.  The
41       same WWW::RobotRules object can be used for one or more parsed /ro‐
42       bots.txt files on any number of hosts.
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44       The following methods are provided:
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46       $rules = WWW::RobotRules->new($robot_name)
47           This is the constructor for WWW::RobotRules objects.  The first
48           argument given to new() is the name of the robot.
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50       $rules->parse($robot_txt_url, $content, $fresh_until)
51           The parse() method takes as arguments the URL that was used to
52           retrieve the /robots.txt file, and the contents of the file.
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54       $rules->allowed($uri)
55           Returns TRUE if this robot is allowed to retrieve this URL.
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57       $rules->agent([$name])
58           Get/set the agent name. NOTE: Changing the agent name will clear
59           the robots.txt rules and expire times out of the cache.
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ROBOTS.TXT

62       The format and semantics of the "/robots.txt" file are as follows (this
63       is an edited abstract of <http://www.robotstxt.org/wc/norobots.html> ):
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65       The file consists of one or more records separated by one or more blank
66       lines. Each record contains lines of the form
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68         <field-name>: <value>
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70       The field name is case insensitive.  Text after the '#' character on a
71       line is ignored during parsing.  This is used for comments.  The fol‐
72       lowing <field-names> can be used:
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74       User-Agent
75          The value of this field is the name of the robot the record is
76          describing access policy for.  If more than one User-Agent field is
77          present the record describes an identical access policy for more
78          than one robot. At least one field needs to be present per record.
79          If the value is '*', the record describes the default access policy
80          for any robot that has not not matched any of the other records.
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82          The User-Agent fields must occur before the Disallow fields.  If a
83          record contains a User-Agent field after a Disallow field, that con‐
84          stitutes a malformed record.  This parser will assume that a blank
85          line should have been placed before that User-Agent field, and will
86          break the record into two.  All the fields before the User-Agent
87          field will constitute a record, and the User-Agent field will be the
88          first field in a new record.
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90       Disallow
91          The value of this field specifies a partial URL that is not to be
92          visited. This can be a full path, or a partial path; any URL that
93          starts with this value will not be retrieved
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ROBOTS.TXT EXAMPLES

96       The following example "/robots.txt" file specifies that no robots
97       should visit any URL starting with "/cyberworld/map/" or "/tmp/":
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99         User-agent: *
100         Disallow: /cyberworld/map/ # This is an infinite virtual URL space
101         Disallow: /tmp/ # these will soon disappear
102
103       This example "/robots.txt" file specifies that no robots should visit
104       any URL starting with "/cyberworld/map/", except the robot called
105       "cybermapper":
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107         User-agent: *
108         Disallow: /cyberworld/map/ # This is an infinite virtual URL space
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110         # Cybermapper knows where to go.
111         User-agent: cybermapper
112         Disallow:
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114       This example indicates that no robots should visit this site further:
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116         # go away
117         User-agent: *
118         Disallow: /
119
120       This is an example of a malformed robots.txt file.
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122         # robots.txt for ancientcastle.example.com
123         # I've locked myself away.
124         User-agent: *
125         Disallow: /
126         # The castle is your home now, so you can go anywhere you like.
127         User-agent: Belle
128         Disallow: /west-wing/ # except the west wing!
129         # It's good to be the Prince...
130         User-agent: Beast
131         Disallow:
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133       This file is missing the required blank lines between records.  How‐
134       ever, the intention is clear.
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NAME

SYNOPSIS

DESCRIPTION

ROBOTS.TXT

ROBOTS.TXT EXAMPLES

SEE ALSO