Class: RobotRules

Inherits:
Object
  • Object
show all
Defined in:
lib/robot_rules.rb

Overview

Based on Perl’s WWW::RobotRules module, by Gisle Aas.

Instance Method Summary collapse

Constructor Details

#initialize(user_agent) ⇒ RobotRules 



12
13
14
15
16
 
# File 'lib/robot_rules.rb', line 12

def initialize( user_agent )
  @user_agent = user_agent.scan(/\S+/).first.sub(%r{/.*},  
"").downcase
  @rules      = Hash.new { |rules, rule| rules[rule] = Array.new }
end

Instance Method Details

#allowed?(text_uri) ⇒ Boolean 



67
68
69
70
71
72
73
74
75
 
# File 'lib/robot_rules.rb', line 67

def allowed?( text_uri )
  uri      = URI.parse(text_uri)
  location = "#{uri.host}:#{uri.port}"
  path     = uri.path

  return true unless %w{http https}.include?(uri.scheme)

  not @rules[location].any? { |rule| path.index(rule) == 0 }
end

#parse(text_uri, robots_data) ⇒ Object 



18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
 
# File 'lib/robot_rules.rb', line 18

def parse( text_uri, robots_data )
  uri      = URI.parse(text_uri)
  location = "#{uri.host}:#{uri.port}"
  @rules.delete(location)

  rules      = robots_data.split(/[\015\012]+/).map { |rule| rule.sub(/\s*#.*$/, "") }
  anon_rules = Array.new
  my_rules   = Array.new
  current    = anon_rules
  rules.each do |rule|
    case rule
    when /^\s*User-Agent\s*:\s*(.+?)\s*$/i
      break unless my_rules.empty?

      current = if $1 == "*"
        anon_rules
      elsif $1.downcase.index(@user_agent)
        my_rules
      else
        nil
      end
    when /^\s*Disallow\s*:\s*(.*?)\s*$/i
      next if current.nil?

      if $1.empty?
        current << nil
      else
        disallow = URI.parse($1)

        next unless disallow.scheme.nil? or disallow.scheme == uri.scheme
        next unless disallow.port.nil?   or disallow.port == uri.port
        next unless disallow.host.nil?   or disallow.host.downcase == uri.host.downcase

        disallow = disallow.path
        disallow = "/" if disallow.empty?
        disallow = "/#{disallow}" unless disallow[0] == ?/

        current << disallow
      end
    end
  end

  @rules[location] = if my_rules.empty?
    anon_rules.compact
  else
    my_rules.compact
  end
end