Class: RobotRules

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

Overview

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

Instance Method Summary collapse

Constructor Details

#initialize(user_agent) ⇒ RobotRules

Returns a new instance of RobotRules.



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# File 'lib/spider/robot_rules.rb', line 14

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

Returns:

  • (Boolean) 


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# File 'lib/spider/robot_rules.rb', line 72

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 



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# File 'lib/spider/robot_rules.rb', line 20

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