Class: RDF::Microdata::Reader

Inherits:
Reader
  • Object
show all
Includes:
Expansion, Util::Logger
Defined in:
lib/rdf/microdata/reader.rb,
lib/rdf/microdata/reader/nokogiri.rb

Overview

An Microdata parser in Ruby

Based on processing rules, amended with the following:

See Also:

Author:

Defined Under Namespace

Modules: Nokogiri

Constant Summary collapse

URL_PROPERTY_ELEMENTS = 
%w(a area audio embed iframe img link object source track video)

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Expansion

#expand, #rule

Constructor Details

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

Initializes the Microdata reader instance.

Parameters:

  • input (Nokogiri::HTML::Document, Nokogiri::XML::Document, IO, File, String) (defaults to: $stdin) —

    the input stream to read

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

    any additional options

Options Hash (**options):

  • :encoding (Encoding) — default: Encoding::UTF_8 —

    the encoding of the input stream (Ruby 1.9+)

  • :validate (Boolean) — default: false —

    whether to validate the parsed statements and values

  • :canonicalize (Boolean) — default: false —

    whether to canonicalize parsed literals

  • :intern (Boolean) — default: true —

    whether to intern all parsed URIs

  • :base_uri (#to_s) — default: nil —

    the base URI to use when resolving relative URIs

  • :registry (#to_s)

Yields:

  • (reader) —

    self

Yield Parameters:

  • reader (RDF::Reader)

Yield Returns:

  • (void) —

    ignored

Raises:

  • (Error) —

    Raises RDF::ReaderError when validating



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# File 'lib/rdf/microdata/reader.rb', line 97

def initialize(input = $stdin, **options, &block)
  super do
    @library = :nokogiri

    require "rdf/microdata/reader/#{@library}"
    @implementation = Nokogiri
    self.extend(@implementation)

    input.rewind if input.respond_to?(:rewind)
    initialize_html(input, **options) rescue log_fatal($!.message, exception: RDF::ReaderError)

    log_error("Empty document") if root.nil?
    log_error(doc_errors.map(&:message).uniq.join("\n")) if !doc_errors.empty?

    log_debug('', "library = #{@library}")

    # Load registry
    begin
      registry_uri = options[:registry] || RDF::Microdata::DEFAULT_REGISTRY
      log_debug('', "registry = #{registry_uri.inspect}")
      Registry.load_registry(registry_uri)
    rescue JSON::ParserError => e
      log_fatal("Failed to parse registry: #{e.message}", exception: RDF::ReaderError) if (root.nil? && validate?)
    end
    
    if block_given?
      case block.arity
        when 0 then instance_eval(&block)
        else block.call(self)
      end
    end
  end
end

Instance Attribute Details

#implementation ⇒ Module (readonly)

Returns the HTML implementation module for this reader instance.

Returns:

  • (Module) —

    Returns the HTML implementation module for this reader instance.



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# File 'lib/rdf/microdata/reader.rb', line 23

def implementation
  @implementation
end

#memory ⇒ Hash{Object => RDF::Resource} (readonly)

Returns maps RDF elements (items) to resources.

Returns:

  • (Hash{Object => RDF::Resource}) —

    maps RDF elements (items) to resources



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# File 'lib/rdf/microdata/reader.rb', line 26

def memory
  @memory
end

Class Method Details

.options ⇒ Object

Reader options

See Also:



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# File 'lib/rdf/microdata/reader.rb', line 43

def self.options
  super + [
    RDF::CLI::Option.new(
      symbol: :rdfa,
      datatype: TrueClass,
      on: ["--rdfa"],
      description: "Transform and parse as RDFa.") {true},
  ]
end

Instance Method Details

#base_uri ⇒ Hash{Symbol => RDF::URI}

Returns the base URI determined by this reader.

Examples:

reader.prefixes[:dc]  #=> RDF::URI('http://purl.org/dc/terms/')

Returns:

  • (Hash{Symbol => RDF::URI})

Since:

  • 0.3.0



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# File 'lib/rdf/microdata/reader.rb', line 36

def base_uri
  @options[:base_uri]
end

#each_statement {|statement| ... }

This method returns an undefined value.

Iterates the given block for each RDF statement in the input.

Reads to graph and performs expansion if required.

Yields:

  • (statement)

Yield Parameters:

  • statement (RDF::Statement) 


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# File 'lib/rdf/microdata/reader.rb', line 139

def each_statement(&block)
  if block_given?
    @callback = block

    # parse
    parse_whole_document(@doc, base_uri)

    if validate? && log_statistics[:error]
      raise RDF::ReaderError, "Errors found during processing"
    end
  end
  enum_for(:each_statement)
end

#each_triple {|subject, predicate, object| ... }

This method returns an undefined value.

Iterates the given block for each RDF triple in the input.

Yields:

  • (subject, predicate, object)

Yield Parameters:

  • subject (RDF::Resource)
  • predicate (RDF::URI)
  • object (RDF::Value) 


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# File 'lib/rdf/microdata/reader.rb', line 161

def each_triple(&block)
  if block_given?
    each_statement do |statement|
      block.call(*statement.to_triple)
    end
  end
  enum_for(:each_triple)
end