Class: RDF::Microdata::RdfaReader

Inherits:
RDFa::Reader
  • Object
show all
Defined in:
lib/rdf/microdata/rdfa_reader.rb

Overview

Update DOM to turn Microdata into RDFa and parse using the RDFa Reader

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input = $stdin, **options) {|reader| ... } ⇒ reader

Initializes the RdfaReader instance.

Parameters:

  • input (IO, File, String) (defaults to: $stdin) —

    the input stream to read

  • options (Hash{Symbol => Object}) —

    any additional options (see RDF::Reader#initialize)

Yields:

  • (reader) —

    self

Yield Parameters:

  • reader (RDF::Reader)

Yield Returns:

  • (void) —

    ignored

Raises:

  • (RDF::ReaderError) —

    if validate



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# File 'lib/rdf/microdata/rdfa_reader.rb', line 31

def initialize(input = $stdin, **options, &block)
  @options = options
  log_debug('', "using RDFa transformation reader")

  input = case input
  when ::Nokogiri::XML::Document, ::Nokogiri::HTML::Document then input
  else
    # Try to detect charset from input
    options[:encoding] ||= input.charset if input.respond_to?(:charset)
    
    # Otherwise, default is utf-8
    options[:encoding] ||= 'utf-8'
    options[:encoding] = options[:encoding].to_s if options[:encoding]
    begin
      input = input.read if input.respond_to?(:read)
      ::Nokogiri::HTML5(input.force_encoding(options[:encoding]), max_parse_errors: 1000)
    rescue LoadError, NoMethodError
      ::Nokogiri::HTML.parse(input, base_uri.to_s, options[:encoding])
    end
  end

  # For all members having @itemscope
  input.css("[itemscope]").each do |item|
    # Get @itemtypes to create @type and @vocab
    item.attribute('itemscope').remove
    if item['itemtype']
      # Only absolute URLs
      types = item.attribute('itemtype').
        remove.
        to_s.
        split(/\s+/).
        select {|t| RDF::URI(t).absolute?}

      item['typeof'] = types.join(' ') unless types.empty?
      if vocab = types.first
        vocab = begin
          type_vocab = vocab.to_s.sub(/([\/\#])[^\/\#]*$/, '\1')
          Registry.new(type_vocab) if type_vocab
        end
        item['vocab'] = vocab.uri.to_s if vocab
      end
    end
    item['typeof'] ||= ''

    # Change each itemid attribute to an resource attribute with the same value
    if item['itemid']
      id = item.attribute('itemid').remove
      item['resource'] = id
    end
  end

  # Add @resource for all itemprop values of object based on a @data value
  input.css("object[itemprop][data]").each do |item|
    item['resource'] ||= item['data']
  end

  # Replace all @itemprop values with @property
  input.css("[itemprop]").each {|item| item['property'] = item.attribute('itemprop').remove}

  # Wrap all @itemref properties
  input.css("[itemref]").each do |item|
    item_vocab = item['vocab'] || item.ancestors.detect {|a| a.attribute('vocab')}
    item_vocab = item_vocab.to_s if item_vocab

    item.attribute('itemref').remove.to_s.split(/\s+/).each do |ref|
      if referenced = input.css("##{ref}")
        # Add @vocab to referenced using the closest ansestor having @vocab of item.
        # If the element with id reference has no resource attribute, add a resource attribute whose value is a NUMBER SIGN U+0023 followed by reference to the element.
        # If the element with id reference has no typeof attribute, add a typeof="rdfa:Pattern" attribute to the element.
        referenced.wrap(%(<div vocab="#{item_vocab}" resource="##{ref}" typeof="rdfa:Pattern" />))

        # Add a link child element to the element that represents the item, with a rel="rdfa:copy" attribute and an href attribute whose value is a NUMBER SIGN U+0023 followed by reference
        link = ::Nokogiri::XML::Node.new('link', input)
        link['rel'] = 'rdfa:copy'
        link['href'] = "##{ref}"
        item << link
      end
    end
  end

  @rdfa = input
  log_debug('', "Transformed document: #{input.to_html}")

  options = options.merge(
    library: :nokogiri,
    reference_folding: true,
    host_language: :html5,
    version: :"rdfa1.1")

  # Rely on RDFa reader
  super(input, **options, &block)
end

Instance Attribute Details

#rdfa ⇒ RDF::HTML::Document (readonly)

The transformed DOM using RDFa

Returns:

  • (RDF::HTML::Document) 


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# File 'lib/rdf/microdata/rdfa_reader.rb', line 9

def rdfa
  @rdfa
end

Class Method Details

.format(klass = nil) ⇒ Object 



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# File 'lib/rdf/microdata/rdfa_reader.rb', line 11

def self.format(klass = nil)
  if klass.nil?
    RDF::Microdata::Format
  else
    super
  end
end