After several months of gathering updates for RDF.rb, we’ve released version 0.3.4 with several new features:

  • Update to BGP query model to support SPARQL semantics,
  • Expandable Litereal support, to allow further implementation of XSD datatypes outside of RDF.rb (see RDF::XSD gem),
  • More advanced content type detection to allow better selection of the appropriate reader from those available on the client. (Includes selecting among HTML types, such as Microdata and RDFa)
  • Improved CLI with the rdf executable providing access to all loaded readers and writers for cross-language serialization and deserialization.

As an example of format detection, consider the following:

require 'linkeddata'
RDF::Graph.load("http://greggkellogg.net/foaf.ttl")

should load Turtle or N3 readers if installed. This becomes more important for ambiguous file types, such as HTML, which could be either RDFa or Microdata, and application/xml, which could be TriX, RDF/XML or even RDFa.

See documentation for more specifics on this version of RDF.rb. Note that I’ve attempted to incorporate suggestions for improving the documentation.

Most of the reader/writer gems have been updated to match this release, in particular JSON::LD, RDF::Microdata, RDF::N3, [RDF::RDFa][], [RDF::RDFXML][], and RDF::Turtle. A future update to the linkeddata gem should reference the latest versions of each, but a simple gem update will work too.

There is a slight semantic change for repositories to support SPARQL: a context of false should not match a variable context. This is straight out of SPARQL semantics. Repository implementors who have provided custom implementations of #query_pattern should check behavior against rdf-spec version 0.3.4 to verify correct operation.

Next up is a release of SPARQL implemented in pure Ruby. This gem provides full support for SPARQL 1.0 queries.