Class: Banzai::Filter::FootnoteFilter

Inherits:
HTML::Pipeline::Filter
  • Object
show all
Includes:
Concerns::PipelineTimingCheck
Defined in:
lib/banzai/filter/footnote_filter.rb

Overview

This filter adds a random number to each footnote (the same number can be used for a single render). So you get ‘id=fn-1-4335` and `id=fn-foot-4335`.

Constant Summary collapse

FOOTNOTE_ID_PREFIX = 
'fn-'
'fnref-'
FOOTNOTE_LI_REFERENCE_PATTERN = 
/\A#{FOOTNOTE_ID_PREFIX}.+\z/
/\A#{FOOTNOTE_LINK_ID_PREFIX}.+\z/
CSS_SECTION = 
"section[data-footnotes]"
XPATH_SECTION = 
Gitlab::Utils::Nokogiri.css_to_xpath(CSS_SECTION).freeze
CSS_FOOTNOTE = 
'sup > a[data-footnote-ref]'
XPATH_FOOTNOTE = 
Gitlab::Utils::Nokogiri.css_to_xpath(CSS_FOOTNOTE).freeze
FOOTNOTE_LIMIT =

Limit of how many footnotes we will process. Protects against pathological number of footnotes.

1000

Constants included from Concerns::PipelineTimingCheck

Concerns::PipelineTimingCheck::MAX_PIPELINE_SECONDS

Instance Method Summary collapse

Methods included from Concerns::PipelineTimingCheck

#exceeded_pipeline_max?

Instance Method Details

#call ⇒ Object 



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# File 'lib/banzai/filter/footnote_filter.rb', line 36

def call
  # Sanitization stripped off the section class - add it back in
  return doc if doc.xpath(XPATH_FOOTNOTE).count > 1000
  return doc unless section_node = doc.at_xpath(XPATH_SECTION)

  section_node.append_class('footnotes')

  rand_suffix = "-#{random_number}"
  modified_footnotes = {}

  doc.xpath(XPATH_FOOTNOTE).each do |link_node|
    next unless link_node[:id]

    ref_num = link_node[:id].delete_prefix(FOOTNOTE_LINK_ID_PREFIX)
    ref_num.gsub!(/[[:punct:]]/, '\\\\\&')

    css = "section[data-footnotes] li[id=#{fn_id(ref_num)}]"
    node_xpath = Gitlab::Utils::Nokogiri.css_to_xpath(css)
    footnote_node = doc.at_xpath(node_xpath)

    next unless footnote_node || modified_footnotes[ref_num]

    link_node[:href] += rand_suffix
    link_node[:id]   += rand_suffix

    # Sanitization stripped off class - add it back in
    link_node.parent.append_class('footnote-ref')

    next if modified_footnotes[ref_num]

    footnote_node[:id] += rand_suffix
    backref_node        = footnote_node.at_css("a[href=\"##{fnref_id(ref_num)}\"]")

    if backref_node
      backref_node[:href] += rand_suffix

      footnote_id = backref_node['data-footnote-backref-idx']
      backref_node[:title] = format(_("Back to reference %{footnote_id}"), footnote_id: footnote_id)
      backref_node['aria-label'] = backref_node[:title]
      backref_node.append_class('footnote-backref')
    end

    modified_footnotes[ref_num] = true
  end

  doc
end