Module: Sinatra::SPARQL::Helpers

Defined in:
vendor/bundler/ruby/2.6.0/bundler/gems/sparql-2d2905435bf8/lib/sinatra/sparql.rb

Overview

Helper methods.

Instance Method Summary collapse

Instance Method Details

#service_description(options = {}) ⇒ RDF::Graph

This is useful when a GET request is performed against a SPARQL endpoint and no query is performed. Provide a set of datasets, including a default dataset along with optional triple count, dump location, and description of the dataset.

The results are serialized using content negotiation. For text/html, authors should generate RDFa for the serivce description directly.

Parameters:

Options Hash (options):

  • :repository (RDF::Enumerable) —

    An enumerable, typically a type of RDF::Repository containing the dataset used for queries against the service.

  • :endpoint (RDF::URI, #to_s) —

    URI of the service endpoint, defaults to "/sparql" in the current realm.

Returns:

See Also:



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# File 'vendor/bundler/ruby/2.6.0/bundler/gems/sparql-2d2905435bf8/lib/sinatra/sparql.rb', line 30

def service_description(options = {})
  repository = options[:repository]

  g = RDF::Graph.new
  sd = RDF::URI("http://www.w3.org/ns/sparql-service-description#")
  void = RDF::URI("http://rdfs.org/ns/void#")

  node = RDF::Node.new
  g << [node, RDF.type, sd.join("#Service")]
  g << [node, sd.join("#endpoint"), options[:endpoint] || url("/sparql")]
  g << [node, sd.join("#supportedLanguage"), sd.join("#SPARQL11Query")]

  # Result formats, both RDF and SPARQL Results.
  # FIXME: We should get this from the avaliable serializers
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/RDF_XML")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/Turtle")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/RDFa")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/N-Triples")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/SPARQL_Results_XML")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/SPARQL_Results_JSON")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/SPARQL_Results_CSV")]
  g << [node, sd.join("#resultFormat"), RDF::URI("http://www.w3.org/ns/formats/SPARQL_Results_TSV")]

  # Features
  g << [node, sd.join("#feature"), sd.join("#DereferencesURIs")]

  # Datasets
  ds = RDF::Node.new
  g << [node, sd.join("#defaultDataset"), ds]
  g << [ds, RDF.type, sd.join("#Dataset")]

  # Contexts
  if repository.is_a?(RDF::Enumerable)
    graph_names = {}
    repository.each do |statement|
      graph_names[statement.graph_name] ||= 0
      graph_names[statement.graph_name] += 1
    end
    
    graph_names.each do |name, count|
      bn = RDF::Node.new
      if name
        # Add named graphs as namedGraphs
        g << [ds, sd.join("#namedGraph"), bn]
        g << [bn, RDF.type, sd.join("#NamedGraph")]
        g << [bn, sd.join("#name"), name]
        graph = RDF::Node.new
        g << [bn, sd.join("#graph"), graph]
        bn = graph
      else
        # Default graph
        g << [ds, sd.join("#defaultGraph"), bn]
        g << [bn, RDF.type, sd.join("#Graph")]
      end
      g << [bn, void.join("#triples"), count]
    end
  end
  g
end