Class: RDF::Vocabulary

Inherits:
Object
  • Object
show all
Defined in:
lib/rdf/vocab/extensions.rb

Defined Under Namespace

Modules: VocabFormatExtensions

Class Method Summary collapse

Class Method Details

._orig_each {|klass| ... } ⇒ Enumerator

Enumerates known RDF vocabulary classes.

Yields:

  • (klass)

Yield Parameters:

  • klass (Class)

Returns:

  • (Enumerator) 


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# File 'lib/rdf/vocab/extensions.rb', line 17

alias_method :_orig_each, :each

.each(&block) ⇒ Object 



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# File 'lib/rdf/vocab/extensions.rb', line 18

def each(&block)
  if self.equal?(Vocabulary)
    # This is needed since all vocabulary classes are defined using
    # Ruby's autoloading facility, meaning that `@@subclasses` will be
    # empty until each subclass has been touched or require'd.
    RDF::Vocab::VOCABS.each do |n, params|
      clsname = params.fetch(:class_name, n.to_s.upcase).to_sym
      RDF::Vocab.const_get(clsname) # Forces class to load
    end unless @classes_loaded
    @classes_loaded = true
  end
  _orig_each(&block)
end

.to_html(graph: nil, prefixes: nil, jsonld: nil, template: nil) ⇒ String

Generate HTML+RDFa representation, specific to vocabularies. This uses generated JSON-LD and a Haml template.

Parameters:

  • :graph (RDF::Queryable) —

    Optional graph, otherwise uses statements from vocabulary.

  • Prefixes (Hash{#to_sym => String}) —

    to add to output

  • jsonld (String, Hash) (defaults to: nil) —

    If not provided, the ‘to_jsonld` method is used to generate it.

  • template (String) (defaults to: nil) —

    The path to a Haml or ERB template used to generate the output using the JSON-LD serialization

Returns:

  • (String) 


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# File 'lib/rdf/vocab/extensions.rb', line 275

def to_html(graph: nil, prefixes: nil, jsonld: nil, template: nil)
  # Find namespaces used in the vocabulary
  graph = RDF::Graph.new {|g| each_statement {|s| g << s}} if graph.nil? || graph.empty?

  # Get JSON as an object
  json = case jsonld
  when String then ::JSON.parse(File.read jsonld)
  when Hash   then jsonld
  else
    ::JSON.parse(to_jsonld(graph: graph, prefixes: prefixes))
  end
  raise "Expected JSON-LD data within the '@graph' key" unless json.has_key?('@graph')

  template ||= File.expand_path("../../../../etc/template.erb", __FILE__)

  prefixes = vocab_prefixes(graph).merge(prefixes || {})
  prefixes[:owl] = RDF::OWL.to_uri.to_s

  # Make sure ontology is typed
  json['@graph']['@type'] ||= ['owl:Ontology']

  jld_context = ::JSON::LD::Context.new.parse([json['@context'], json['@graph']['@context']])

  # Expand the JSON-LD to normalize accesses
  expanded = ::JSON::LD::API.expand(json).first
  expanded.delete('@reverse')

  # Re-compact keys
  expanded = expanded.inject({}) do |memo, (k, v)|
    term = RDF::Vocabulary.find_term(k)
    k = term.pname if term
    memo.merge(k => v)
  end

  # Normalize label accessors
  expanded['rdfs:label'] ||= %w(dc:title dc11:title skos:prefLabel).inject(nil) do |memo, key|
    memo || expanded[key]
  end || [{'@value' => json['@graph']['@id']}]
  %w(rdfs_classes rdfs_properties rdfs_datatypes rdfs_instances).each do |section|
    next unless json['@graph'][section]
    json['@graph'][section].each do |node|
      node['rdfs:label'] ||= %w(dc:title dc11:title skos:prefLabel).inject do |memo, key|
        memo || node[key]
      end || [{'@value' => node['@id']}]
    end
  end

  # Expand each part separately, as well.
  %w(rdfs_classes rdfs_properties rdfs_datatypes rdfs_instances).each do |section|
    next unless json['@graph'][section]
    expanded_section = ::JSON::LD::API.expand(json['@graph'][section], expandContext: jld_context)
    # Re-compact keys
    expanded[section] = expanded_section.map do |node|
      node.inject({}) do |memo, (k, v)|
        term = RDF::Vocabulary.find_term(k)
        k = term.pname if term
        memo.merge(k => v)
      end
    end
  end

  # Template invoked with expanded JSON-LD with outer object including `rdfs_classes`, `rdfs_properties`, and `rdf_instances` sections.
  case template
  when /.haml$/
    require 'haml'
    haml = Haml::Engine.new(File.read(template))
    haml.render(self, ont: expanded, context: json['@context'], prefixes: prefixes)
  when /.erb$/
    require 'erubis'
    eruby = Erubis::FastEruby.new(File.read(template))
    result = eruby.evaluate(binding: self, ont: expanded, context: json['@context'], prefixes: prefixes)
  else
    raise "Unknown template type #{template}. Should have '.erb' or '.haml' extension"
  end
end

.value_to_html(property, value, tag) ⇒ Object

Create HTML for values (Helper method, needs to be public)



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# File 'lib/rdf/vocab/extensions.rb', line 353

def value_to_html(property, value, tag)
  value.map do |v|
    %(<#{tag} property="#{property}") +
    if v['@value']
      (v['@language'] ? %( lang="#{v['@language']}") : "") +
      (v['@type'] ? %( datatype="#{RDF::URI(v['@type']).pname}") : "") +
      %(>#{v['@value']})
    elsif v['@id']
      %( resource="#{RDF::URI(v['@id']).pname}">#{RDF::URI(v['@id']).pname})
    else
      raise "Unknown value type: #{v.inspect}, #{property}"
    end +
    %(</#{tag}>)
  end.join("\n")
end