Class: MdnQuery::TraverseDom

Inherits:
Object
  • Object
show all
Defined in:
lib/mdn_query/traverse_dom.rb

Overview

A DOM traverser that extracts relevant elements.

Constant Summary collapse

BLACKLIST =

Sections that are blacklisted and excluded from the document.

%w[Specifications Browser_compatibility].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(dom, document: nil, url: nil) ⇒ MdnQuery::TraverseDom

Creates a new DOM traverser.

The given document is used to save the extracted text. If no document is given, a new one is created with the generic title ‘root’ and the given url.

The DOM is not automatically traversed (use #traverse).

Parameters:

  • dom (Nokogiri::HTML::Document) —

    the DOM that is traversed

  • document (MdnQuery::Document) (defaults to: nil) —

    the document to be filled

  • url (String) (defaults to: nil) —

    the URL for the new document if none was provided



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# File 'lib/mdn_query/traverse_dom.rb', line 50

def initialize(dom, document: nil, url: nil)
  @dom = dom
  @document = document || MdnQuery::Document.new('root', url)
  @current_section = @document.section
end

Instance Attribute Details

#current_section ⇒ MdnQuery::Section (readonly)

Returns the current section.

Returns:



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# File 'lib/mdn_query/traverse_dom.rb', line 5

def current_section
  @current_section
end

#document ⇒ MdnQuery::Document (readonly)

Returns the document that contains the extracted text.

Returns:



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# File 'lib/mdn_query/traverse_dom.rb', line 11

def document
  @document
end

#dom ⇒ Nokogiri::HTML::Document (readonly)

Returns the DOM that is traversed.

Returns:

  • (Nokogiri::HTML::Document) —

    the DOM that is traversed



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# File 'lib/mdn_query/traverse_dom.rb', line 8

def dom
  @dom
end

Class Method Details

.create_document(dom, title, url) ⇒ MdnQuery::Document

Creates a new document with the extracted text.

Parameters:

  • dom (Nokogiri::HTML::Document) —

    the DOM that is traversed

  • title (String) —

    the title of the document

  • url (String) —

    the URL to the document on the web

Returns:



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# File 'lib/mdn_query/traverse_dom.rb', line 22

def self.create_document(dom, title, url)
  document = MdnQuery::Document.new(title, url)
  fill_document(dom, document)
end

.fill_document(dom, document) ⇒ MdnQuery::Document

Fills a document with the extracted text.

Parameters:

  • dom (Nokogiri::HTML::Document) —

    the DOM that is traversed

  • document (MdnQuery::Document) —

    the document to be filled

Returns:



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# File 'lib/mdn_query/traverse_dom.rb', line 32

def self.fill_document(dom, document)
  traverser = new(dom, document: document)
  traverser.traverse
  traverser.document
end

Instance Method Details

#blacklisted?(id) ⇒ Boolean

Returns whether the id is blacklisted.

Parameters:

  • id (String) —

    the id to be tested

Returns:

  • (Boolean) 


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# File 'lib/mdn_query/traverse_dom.rb', line 123

def blacklisted?(id)
  BLACKLIST.include?(id)
end

#create_child(desired_level, name) ⇒ MdnQuery::Section

Creates a new child section on the appropriate parent section.

Parameters:

  • desired_level (Fixnum) —

    the desired level for the child section

  • name (String) —

    the name and title of the child section

Returns:



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# File 'lib/mdn_query/traverse_dom.rb', line 61

def create_child(desired_level, name)
  until @current_section.level < desired_level ||
        @current_section.parent.nil?
    @current_section = @current_section.parent
  end
  @current_section = @current_section.create_child(name)
end

#traverse ⇒ void

This method returns an undefined value.

Traverses the DOM and extracts relevant informations into the document.



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# File 'lib/mdn_query/traverse_dom.rb', line 72

def traverse
  unless @dom.css('div.nonStandard').empty?
    @current_section.append_text("\n> ***Non-standard***\n")
  end
  blacklist_level = nil
  @dom.children.each do |child|
    if child_blacklisted?(child, blacklist_level)
      if blacklist_level.nil?
        blacklist_level = child.name.match(/\Ah(?<level>\d)\z/)[:level]
      end
      next
    end
    blacklist_level = nil
    case child.name
    when 'p'
      @current_section.append_text(child.text)
    when 'ul'
      @current_section.append_text(convert_list(child))
    when 'dl'
      @current_section.append_text(convert_description(child))
    when 'pre'
      if child[:class].nil?
        @current_section.append_code(child.text)
        next
      end
      match = child[:class].match(/brush:\s*(?<lang>\w+)/)
      if match.nil?
        @current_section.append_code(child.text)
      else
        lang = match[:lang]
        lang = 'javascript' if lang == 'js'
        @current_section.append_code(child.text, language: lang)
      end
    when /\Ah(?<level>\d)\z/
      level = $LAST_MATCH_INFO[:level].to_i
      create_child(level, child[:id].tr('_', ' '))
    when 'table'
      @current_section.append_text(convert_table(child))
    when 'div'
      next if child[:class].nil?
      if child[:class].include?('note') || child[:class].include?('warning')
        @current_section.append_text("\n> #{child.text.strip}\n")
      end
    end
  end
end