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