discourse/lib/excerpt_parser.rb

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class ExcerptParser < Nokogiri::XML::SAX::Document
attr_reader :excerpt
SPAN_REGEX = /<\s*span[^>]*class\s*=\s*['|"]excerpt['|"][^>]*>/
def initialize(length, options=nil)
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@length = length
@excerpt = ""
@current_length = 0
options || {}
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@strip_links = options[:strip_links] == true
@text_entities = options[:text_entities] == true
@markdown_images = options[:markdown_images] == true
@keep_newlines = options[:keep_newlines] == true
@keep_emojis = options[:keep_emojis] == true
@start_excerpt = false
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end
def self.get_excerpt(html, length, options)
html ||= ''
length = html.length if html.include?('excerpt') && SPAN_REGEX === html
me = self.new(length, options)
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parser = Nokogiri::HTML::SAX::Parser.new(me)
catch(:done) do
parser.parse(html)
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end
excerpt = me.excerpt.strip
excerpt = CGI.unescapeHTML(excerpt) if options[:text_entities] == true
excerpt
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end
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def escape_attribute(v)
return "" unless v
v = v.dup
v.gsub!("&", "&amp;")
v.gsub!("\"", "&#34;")
v.gsub!("<", "&lt;")
v.gsub!(">", "&gt;")
v
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end
def include_tag(name, attributes)
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characters("<#{name} #{attributes.map{|k,v| "#{k}=\"#{escape_attribute(v)}\""}.join(' ')}>", false, false, false)
end
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def start_element(name, attributes=[])
case name
when "img"
attributes = Hash[*attributes.flatten]
if @keep_emojis && attributes["class"] == 'emoji'
return include_tag(name, attributes)
end
# If include_images is set, include the image in markdown
characters("!") if @markdown_images
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if attributes["alt"]
characters("[#{attributes["alt"]}]")
elsif attributes["title"]
characters("[#{attributes["title"]}]")
else
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characters("[#{I18n.t 'excerpt_image'}]")
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end
characters("(#{attributes['src']})") if @markdown_images
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when "a"
unless @strip_links
include_tag(name, attributes)
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@in_a = true
end
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when "aside"
@in_quote = true
when "div", "span"
if attributes.include?(["class", "excerpt"])
@excerpt = ""
@current_length = 0
@start_excerpt = true
end
# Preserve spoilers
if attributes.include?(["class", "spoiler"])
include_tag("span", attributes)
@in_spoiler = true
end
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end
end
def end_element(name)
case name
when "a"
unless @strip_links
characters("</a>",false, false, false)
@in_a = false
end
when "p", "br"
if @keep_newlines
characters("<br>", false, false, false)
else
characters(" ")
end
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when "aside"
@in_quote = false
when "div", "span"
throw :done if @start_excerpt
characters("</span>", false, false, false) if @in_spoiler
@in_spoiler = false
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end
end
def characters(string, truncate = true, count_it = true, encode = true)
return if @in_quote
encode = encode ? lambda{|s| ERB::Util.html_escape(s)} : lambda {|s| s}
if count_it && @current_length + string.length > @length
length = [0, @length - @current_length - 1].max
@excerpt << encode.call(string[0..length]) if truncate
@excerpt << (@text_entities ? "..." : "&hellip;")
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@excerpt << "</a>" if @in_a
throw :done
end
@excerpt << encode.call(string)
@current_length += string.length if count_it
end
end