523 lines
18 KiB
Ruby
523 lines
18 KiB
Ruby
# encoding: utf-8
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require 'rubygems'
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require 'nokogiri'
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require 'guess_html_encoding'
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module Readability
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class Document
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DEFAULT_OPTIONS = {
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:retry_length => 250,
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:min_text_length => 25,
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:remove_unlikely_candidates => true,
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:weight_classes => true,
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:clean_conditionally => true,
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:remove_empty_nodes => true,
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:min_image_width => 130,
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:min_image_height => 80,
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:ignore_image_format => [],
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:blacklist => nil,
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:whitelist => nil
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}.freeze
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REGEXES = {
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:unlikelyCandidatesRe => /combx|comment|community|disqus|extra|foot|header|menu|remark|rss|shoutbox|sidebar|sponsor|ad-break|agegate|pagination|pager|popup/i,
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:okMaybeItsACandidateRe => /and|article|body|column|main|shadow/i,
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:positiveRe => /article|body|content|entry|hentry|main|page|pagination|post|text|blog|story/i,
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:negativeRe => /combx|comment|com-|contact|foot|footer|footnote|masthead|media|meta|outbrain|promo|related|scroll|shoutbox|sidebar|sponsor|shopping|tags|tool|widget/i,
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:divToPElementsRe => /<(a|blockquote|dl|div|img|ol|p|pre|table|ul)/i,
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:replaceBrsRe => /(<br[^>]*>[ \n\r\t]*){2,}/i,
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:replaceFontsRe => /<(\/?)font[^>]*>/i,
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:trimRe => /^\s+|\s+$/,
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:normalizeRe => /\s{2,}/,
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:killBreaksRe => /(<br\s*\/?>(\s| ?)*){1,}/,
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:videoRe => /http:\/\/(www\.)?(youtube|vimeo)\.com/i
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}
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attr_accessor :options, :html, :best_candidate, :candidates, :best_candidate_has_image
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def initialize(input, options = {})
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@options = DEFAULT_OPTIONS.merge(options)
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@input = input
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if RUBY_VERSION =~ /^(1\.9|2)/ && !@options[:encoding]
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@input = GuessHtmlEncoding.encode(@input, @options[:html_headers]) unless @options[:do_not_guess_encoding]
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@options[:encoding] = @input.encoding.to_s
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end
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@input = @input.gsub(REGEXES[:replaceBrsRe], '</p><p>').gsub(REGEXES[:replaceFontsRe], '<\1span>')
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@remove_unlikely_candidates = @options[:remove_unlikely_candidates]
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@weight_classes = @options[:weight_classes]
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@clean_conditionally = @options[:clean_conditionally]
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@best_candidate_has_image = true
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make_html
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handle_exclusions!(@options[:whitelist], @options[:blacklist])
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end
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def images(content=nil, reload=false)
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begin
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require 'fastimage'
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rescue LoadError
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raise "Please install fastimage in order to use the #images feature."
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end
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@best_candidate_has_image = false if reload
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prepare_candidates
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list_images = []
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tested_images = []
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content = @best_candidate[:elem] unless reload
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return list_images if content.nil?
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elements = content.css("img").map(&:attributes)
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elements.each do |element|
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next unless element["src"]
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url = element["src"].value
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height = element["height"].nil? ? 0 : element["height"].value.to_i
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width = element["width"].nil? ? 0 : element["width"].value.to_i
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if url =~ /\Ahttps?:\/\//i && (height.zero? || width.zero?)
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image = get_image_size(url)
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next unless image
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else
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image = {:width => width, :height => height}
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end
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image[:format] = File.extname(url).gsub(".", "")
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if tested_images.include?(url)
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debug("Image was tested: #{url}")
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next
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end
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tested_images.push(url)
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if image_meets_criteria?(image)
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list_images << url
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else
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debug("Image discarded: #{url} - height: #{image[:height]} - width: #{image[:width]} - format: #{image[:format]}")
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end
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end
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(list_images.empty? and content != @html) ? images(@html, true) : list_images
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end
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def images_with_fqdn_uris!(source_uri)
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images_with_fqdn_uris(@html, source_uri)
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end
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def images_with_fqdn_uris(document = @html.dup, source_uri)
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uri = URI.parse(source_uri)
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host = uri.host
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scheme = uri.scheme
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port = uri.port # defaults to 80
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base = "#{scheme}://#{host}:#{port}/"
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images = []
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document.css("img").each do |elem|
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begin
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elem['src'] = URI.join(base,elem['src']).to_s if URI.parse(elem['src']).host == nil
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images << elem['src'].to_s
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rescue URI::InvalidURIError => exc
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elem.remove
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end
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end
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images(document,true)
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end
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def get_image_size(url)
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w, h = FastImage.size(url)
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raise "Couldn't get size." if w.nil? || h.nil?
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{:width => w, :height => h}
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rescue => e
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debug("Image error: #{e}")
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nil
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end
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def image_meets_criteria?(image)
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return false if options[:ignore_image_format].include?(image[:format].downcase)
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image[:width] >= (options[:min_image_width] || 0) && image[:height] >= (options[:min_image_height] || 0)
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end
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def title
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title = @html.css("title").first
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title ? title.text : nil
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end
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# Look through the @html document looking for the author
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# Precedence Information here on the wiki: (TODO attach wiki URL if it is accepted)
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# Returns nil if no author is detected
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def author
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# Let's grab this author:
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# <meta name="dc.creator" content="Finch - http://www.getfinch.com" />
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author_elements = @html.xpath('//meta[@name = "dc.creator"]')
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unless author_elements.empty?
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author_elements.each do |element|
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return element['content'].strip if element['content']
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end
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end
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# Now let's try to grab this
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# <span class="byline author vcard"><span>By</span><cite class="fn">Austin Fonacier</cite></span>
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# <div class="author">By</div><div class="author vcard"><a class="url fn" href="http://austinlivesinyoapp.com/">Austin Fonacier</a></div>
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author_elements = @html.xpath('//*[contains(@class, "vcard")]//*[contains(@class, "fn")]')
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unless author_elements.empty?
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author_elements.each do |element|
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return element.text.strip if element.text
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end
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end
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# Now let's try to grab this
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# <a rel="author" href="http://dbanksdesign.com">Danny Banks (rel)</a>
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# TODO: strip out the (rel)?
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author_elements = @html.xpath('//a[@rel = "author"]')
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unless author_elements.empty?
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author_elements.each do |element|
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return element.text.strip if element.text
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end
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end
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author_elements = @html.xpath('//*[@id = "author"]')
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unless author_elements.empty?
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author_elements.each do |element|
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return element.text.strip if element.text
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end
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end
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end
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def content(remove_unlikely_candidates = :default)
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@remove_unlikely_candidates = false if remove_unlikely_candidates == false
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prepare_candidates
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article = get_article(@candidates, @best_candidate)
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cleaned_article = sanitize(article, @candidates, options)
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if article.text.strip.length < options[:retry_length]
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if @remove_unlikely_candidates
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@remove_unlikely_candidates = false
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elsif @weight_classes
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@weight_classes = false
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elsif @clean_conditionally
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@clean_conditionally = false
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else
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# nothing we can do
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return cleaned_article
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end
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make_html
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content
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else
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cleaned_article
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end
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end
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def get_article(candidates, best_candidate)
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# Now that we have the top candidate, look through its siblings for content that might also be related.
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# Things like preambles, content split by ads that we removed, etc.
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sibling_score_threshold = [10, best_candidate[:content_score] * 0.2].max
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output = Nokogiri::XML::Node.new('div', @html)
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best_candidate[:elem].parent.children.each do |sibling|
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append = false
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append = true if sibling == best_candidate[:elem]
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append = true if candidates[sibling] && candidates[sibling][:content_score] >= sibling_score_threshold
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if sibling.name.downcase == "p"
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link_density = get_link_density(sibling)
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node_content = sibling.text
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node_length = node_content.length
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append = if node_length > 80 && link_density < 0.25
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true
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elsif node_length < 80 && link_density == 0 && node_content =~ /\.( |$)/
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true
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end
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end
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if append
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sibling_dup = sibling.dup # otherwise the state of the document in processing will change, thus creating side effects
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sibling_dup.name = "div" unless %w[div p].include?(sibling.name.downcase)
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output << sibling_dup
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end
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end
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output
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end
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def select_best_candidate(candidates)
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sorted_candidates = candidates.values.sort { |a, b| b[:content_score] <=> a[:content_score] }
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debug("Top 5 candidates:")
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sorted_candidates[0...5].each do |candidate|
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debug("Candidate #{candidate[:elem].name}##{candidate[:elem][:id]}.#{candidate[:elem][:class]} with score #{candidate[:content_score]}")
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end
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best_candidate = sorted_candidates.first || { :elem => @html.css("body").first, :content_score => 0 }
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debug("Best candidate #{best_candidate[:elem].name}##{best_candidate[:elem][:id]}.#{best_candidate[:elem][:class]} with score #{best_candidate[:content_score]}")
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best_candidate
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end
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def get_link_density(elem)
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link_length = elem.css("a").map(&:text).join("").length
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text_length = elem.text.length
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link_length / text_length.to_f
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end
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def class_weight(e)
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weight = 0
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return weight unless @weight_classes
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if e[:class] && e[:class] != ""
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weight -= 25 if e[:class] =~ REGEXES[:negativeRe]
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weight += 25 if e[:class] =~ REGEXES[:positiveRe]
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end
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if e[:id] && e[:id] != ""
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weight -= 25 if e[:id] =~ REGEXES[:negativeRe]
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weight += 25 if e[:id] =~ REGEXES[:positiveRe]
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end
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weight
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end
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ELEMENT_SCORES = {
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'div' => 5,
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'blockquote' => 3,
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'form' => -3,
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'th' => -5
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}.freeze
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def score_node(elem)
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content_score = class_weight(elem)
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content_score += ELEMENT_SCORES.fetch(elem.name.downcase, 0)
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{ :content_score => content_score, :elem => elem }
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end
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def debug(str)
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puts str if options[:debug]
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end
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def sanitize(node, candidates, options = {})
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node.css("h1, h2, h3, h4, h5, h6").each do |header|
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header.remove if class_weight(header) < 0 || get_link_density(header) > 0.33
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end
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node.css("form, object, iframe, embed").each do |elem|
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elem.remove
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end
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if @options[:remove_empty_nodes]
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# remove <p> tags that have no text content - this will also remove p tags that contain only images.
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node.css("p").each do |elem|
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elem.remove if elem.content.strip.empty?
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end
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end
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# Conditionally clean <table>s, <ul>s, and <div>s
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clean_conditionally(node, candidates, "table, ul, div")
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# We'll sanitize all elements using a whitelist
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base_whitelist = @options[:tags] || %w[div p]
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# We'll add whitespace instead of block elements,
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# so a<br>b will have a nice space between them
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base_replace_with_whitespace = %w[br hr h1 h2 h3 h4 h5 h6 dl dd ol li ul address blockquote center]
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# Use a hash for speed (don't want to make a million calls to include?)
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whitelist = Hash.new
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base_whitelist.each {|tag| whitelist[tag] = true }
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replace_with_whitespace = Hash.new
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base_replace_with_whitespace.each { |tag| replace_with_whitespace[tag] = true }
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([node] + node.css("*")).each do |el|
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# If element is in whitelist, delete all its attributes
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if whitelist[el.node_name]
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el.attributes.each { |a, x| el.delete(a) unless @options[:attributes] && @options[:attributes].include?(a.to_s) }
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# Otherwise, replace the element with its contents
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else
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# If element is root, replace the node as a text node
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if el.parent.nil?
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node = Nokogiri::XML::Text.new(el.text, el.document)
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break
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else
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if replace_with_whitespace[el.node_name]
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el.swap(Nokogiri::XML::Text.new(' ' << el.text << ' ', el.document))
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else
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el.swap(Nokogiri::XML::Text.new(el.text, el.document))
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end
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end
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end
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end
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s = Nokogiri::XML::Node::SaveOptions
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save_opts = s::NO_DECLARATION | s::NO_EMPTY_TAGS | s::AS_XHTML
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html = node.serialize(:save_with => save_opts)
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# Get rid of duplicate whitespace
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return html.gsub(/[\r\n\f]+/, "\n" )
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end
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def clean_conditionally(node, candidates, selector)
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return unless @clean_conditionally
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node.css(selector).each do |el|
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weight = class_weight(el)
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content_score = candidates[el] ? candidates[el][:content_score] : 0
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name = el.name.downcase
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if weight + content_score < 0
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el.remove
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debug("Conditionally cleaned #{name}##{el[:id]}.#{el[:class]} with weight #{weight} and content score #{content_score} because score + content score was less than zero.")
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elsif el.text.count(",") < 10
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counts = %w[p img li a embed input].inject({}) { |m, kind| m[kind] = el.css(kind).length; m }
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counts["li"] -= 100
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# For every img under a noscript tag discount one from the count to avoid double counting
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counts["img"] -= el.css("noscript").css("img").length
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content_length = el.text.strip.length # Count the text length excluding any surrounding whitespace
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link_density = get_link_density(el)
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reason = clean_conditionally_reason?(name, counts, content_length, options, weight, link_density)
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if reason
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debug("Conditionally cleaned #{name}##{el[:id]}.#{el[:class]} with weight #{weight} and content score #{content_score} because it has #{reason}.")
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el.remove
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end
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end
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end
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end
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def clean_conditionally_reason?(name, counts, content_length, options, weight, link_density)
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if (counts["img"] > counts["p"]) && (counts["img"] > 1)
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"too many images"
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elsif counts["li"] > counts["p"] && name != "ul" && name != "ol"
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"more <li>s than <p>s"
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elsif counts["input"] > (counts["p"] / 3).to_i
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"less than 3x <p>s than <input>s"
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elsif (content_length < options[:min_text_length]) && (counts["img"] != 1)
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"too short a content length without a single image"
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elsif weight < 25 && link_density > 0.2
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"too many links for its weight (#{weight})"
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elsif weight >= 25 && link_density > 0.5
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"too many links for its weight (#{weight})"
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elsif (counts["embed"] == 1 && content_length < 75) || counts["embed"] > 1
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"<embed>s with too short a content length, or too many <embed>s"
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else
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nil
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end
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end
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private
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# 제거항목 추가항목을 지정한다.
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def handle_exclusions!(whitelist, blacklist)
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return unless whitelist || blacklist
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if blacklist
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elems = @html.css(blacklist)
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if elems
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elems.each do |e|
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e.remove
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end
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end
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end
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if whitelist
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elems = @html.css(whitelist).to_s
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if body = @html.at_css('body')
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body.inner_html = elems
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end
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end
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@input = @html.to_s
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end
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# 코멘트가 제거된 기본 html 노드 반환
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def make_html(whitelist=nil, blacklist=nil)
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@html = Nokogiri::HTML(@input, nil, @options[:encoding])
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# In case document has no body, such as from empty string or redirect
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@html = Nokogiri::HTML('<body />', nil, @options[:encoding]) if @html.css('body').length == 0
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# Remove html comment tags
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@html.xpath('//comment()').each { |i| i.remove }
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end
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def prepare_candidates
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@html.css("script, style").each { |i| i.remove }
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remove_unlikely_candidates! if @remove_unlikely_candidates
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transform_misused_divs_into_paragraphs!
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@candidates = score_paragraphs(options[:min_text_length])
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@best_candidate = select_best_candidate(@candidates)
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end
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# 가망없는 후보자를 제거한다. (명확한 후보자는 제외하고 제거한다.)
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def remove_unlikely_candidates!
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@html.css("*").each do |elem|
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str = "#{elem[:class]}#{elem[:id]}"
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if str =~ REGEXES[:unlikelyCandidatesRe] && str !~ REGEXES[:okMaybeItsACandidateRe] && (elem.name.downcase != 'html') && (elem.name.downcase != 'body')
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debug("Removing unlikely candidate - #{str}")
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elem.remove
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end
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end
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end
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# 잘못 사용되고 있는 DIV를 p로 변환한다.
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def transform_misused_divs_into_paragraphs!
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@html.css("*").each do |elem|
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if elem.name.downcase == "div"
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# transform <div>s that do not contain other block elements into <p>s
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if elem.inner_html !~ REGEXES[:divToPElementsRe]
|
|
debug("Altering div(##{elem[:id]}.#{elem[:class]}) to p");
|
|
elem.name = "p"
|
|
end
|
|
else
|
|
# wrap text nodes in p tags
|
|
# elem.children.each do |child|
|
|
# if child.text?
|
|
# debug("wrapping text node with a p")
|
|
# child.swap("<p>#{child.text}</p>")
|
|
# end
|
|
# end
|
|
end
|
|
end
|
|
end
|
|
|
|
# 가능노드에 점수를 매긴다.
|
|
def score_paragraphs(min_text_length)
|
|
candidates = {}
|
|
@html.css("p,td").each do |elem|
|
|
parent_node = elem.parent
|
|
grand_parent_node = parent_node.respond_to?(:parent) ? parent_node.parent : nil
|
|
inner_text = elem.text
|
|
|
|
# If this paragraph is less than 25 characters, don't even count it.
|
|
next if inner_text.length < min_text_length
|
|
|
|
candidates[parent_node] ||= score_node(parent_node)
|
|
candidates[grand_parent_node] ||= score_node(grand_parent_node) if grand_parent_node
|
|
|
|
content_score = 1
|
|
content_score += inner_text.split(',').length
|
|
content_score += [(inner_text.length / 100).to_i, 3].min
|
|
|
|
candidates[parent_node][:content_score] += content_score
|
|
candidates[grand_parent_node][:content_score] += content_score / 2.0 if grand_parent_node
|
|
end
|
|
|
|
# Scale the final candidates score based on link density. Good content should have a
|
|
# relatively small link density (5% or less) and be mostly unaffected by this operation.
|
|
candidates.each do |elem, candidate|
|
|
candidate[:content_score] = candidate[:content_score] * (1 - get_link_density(elem))
|
|
end
|
|
|
|
candidates
|
|
end
|
|
end
|
|
end
|