plucker.rb

require 'open-uri'
require 'nokogiri'

def pluck_article(url)
    
  # get the raw HTML
  doc = Nokogiri::HTML(open(url))  
  
  # get the paragraphs
  paragraphs = doc.search('p')
  
  # assign points to the parent nodes for each paragraph
  parents = {}
  paragraphs.each do |paragraph|
    points = calculate_points(paragraph)
    if parents.has_key?(paragraph.parent)
      parents[paragraph.parent] += points
    else
      parents[paragraph.parent] = points
    end
  end
  
  # get the parent node with the highest point total
  winner = parents.sort{ |a,b| a[1] <=> b[1] }.last[0]
  
  # return the plucked HTML content
  "<h1>" + doc.search('title').inner_html + "</h1>" + winner.inner_html
end


def calculate_points(paragraph, starting_points = 0)

  # reward for being a new paragraph
  points = starting_points + 20

  # look at the id and class of paragraph and parent
  classes_and_ids = (paragraph.get_attribute('class') || '') + ' ' + 
                    (paragraph.get_attribute('id') || '')  + ' ' + 
                    (paragraph.parent.get_attribute('class') || '')  + ' ' +
                    (paragraph.parent.get_attribute('id') || '') 

  # deduct severely and return if clearly not content
  if classes_and_ids =~ /comment|meta|footer|footnote/
    points -= 3000
    return points
  end
  
  # reward if probably content
  if classes_and_ids =~ /post|hentry|entry|article/
    points += 50
  end  
  
  # look at the actual text of the paragraph
  content = paragraph.content
  
  # deduct if very short
  if content.length < 20
    points -= 50
  end
  
  # reward if long
  if content.length > 100
    points += 50
  end
    
  # deduct if no periods, question marks, or exclamation points
  unless (content.include?('.') or content.include?('?') or content.include?('!'))
    points -= 100
  end
  
  # reward for periods and commas
  points += content.count('.') * 10
  points += content.count(',') * 20  
  
  points

end