Class: HTML::Pipeline::TableOfContentsFilter

Inherits:
Filter
  • Object
show all
Defined in:
lib/html/pipeline/toc_filter.rb

Overview

HTML filter that adds a ‘name’ attribute to all headers in a document, so they can be accessed from a table of contents

Context options:

:toc_minimal_length (required) - Only add the table of contents to text with this number of characters
:toc_header (required) - Introduce the table of contents with this header

Instance Attribute Summary

Attributes inherited from Filter

#context, #result

Instance Method Summary collapse

Methods inherited from Filter

#base_url, call, #current_user, #doc, #has_ancestor?, #html, #initialize, #needs, #parse_html, #repository, to_document, to_html

Constructor Details

This class inherits a constructor from HTML::Pipeline::Filter

Instance Method Details

#call ⇒ Object 



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# File 'lib/html/pipeline/toc_filter.rb', line 13

def call
  headers = Hash.new 0
  was = 1
  toc = ""
  doc.css('h2, h3, h4, h5, h6').each do |node|
    level = node.name.scan(/\d/).first.to_i
    name = node.text.downcase
    name.gsub!(/[^\p{Word}\- ]/u, '') # remove punctuation
    name.gsub!(' ', '-') # replace spaces with dash

    uniq = (headers[name] > 0) ? "-#{headers[name]}" : ''
    headers[name] += 1
    node['id'] = "#{name}#{uniq}"

    if was < level
      while was < level
        toc << "<ul>\n<li>"
        was += 1
      end
    else
      toc << "</li>\n"
      while was > level
        toc << "</ul></li>\n"
        was -= 1
      end
      toc << "<li>"
    end
    toc << "<a href=\"##{name}#{uniq}\">#{node.inner_html}</a>"
  end

  length = 0
  doc.traverse {|node| length += node.text.length if node.text? }
  return doc unless length >= context[:toc_minimal_length]

  while was > 1
    toc << "</li>\n</ul>\n"
    was -= 1
  end
  toc.sub!('<ul>', '<ul class="toc">')

  unless headers.empty?
    first_child = doc.child
    first_child.add_previous_sibling context[:toc_header]
    first_child.add_previous_sibling toc
  end
  doc
end

#validate ⇒ Object 



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# File 'lib/html/pipeline/toc_filter.rb', line 61

def validate
  needs :toc_minimal_length, :toc_header
end