Module: Sinatra::SPARQL::Helpers

Defined in:: lib/sinatra/sparql.rb

Overview

Helper methods.

Instance Method Summary collapse

#dataset(**options) ⇒ RDF::Dataset

This either creates a merge repo, or uses the standard repository for performing the query, based on the parameters passed (default-graph-uri and named-graph-uri).
#service_description(**options) ⇒ RDF::Graph

This is useful when a GET request is performed against a SPARQL endpoint and no query is performed.

Instance Method Details

#dataset(**options) ⇒ `RDF::Dataset`

This either creates a merge repo, or uses the standard repository for performing the query, based on the parameters passed (default-graph-uri and named-graph-uri). Loads from the datasource, unless a graph named by the datasource URI already exists in the repository.

Returns:

(RDF::Dataset)

See Also:

Algebra::Operator::Dataset

# File 'lib/sinatra/sparql.rb', line 112

def dataset(**options)
  logger = options.fetch(:logger, ::Logger.new(false))
  repo = settings.repository
  if %i(default-graph-uri named-graph-uri).any? {|k| options.key?(k)}        
    default_datasets = Array(options[:"default-graph-uri"]).map {|u| RDF::URI(u)}
    named_datasets = Array(options[:"named-graph-uri"]).map {|u| RDF::URI(u)}

    (default_datasets + named_datasets).each do |uri|
      load_opts = {logger: logger, graph_name: uri, base_uri: uri}
      unless repo.has_graph?(uri)
        logger.debug(options) {"=> load #{uri}"}
        repo.load(uri.to_s, **load_opts)
      end
    end

    # Create an aggregate based on queryable having just the bits we want
    aggregate = RDF::AggregateRepo.new(repo)
    named_datasets.each {|name| aggregate.named(name) if repo.has_graph?(name)}
    aggregate.default(*default_datasets.select {|name| repo.has_graph?(name)})
    aggregate
  end || settings.repository
end

#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{Symbol => Object})

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.