IqRdf - RDF Renderering for Ruby and Rails

IqRdf is a RDF renderer for Ruby and Rails. You can use it in any Ruby environment to render Trurtle-, N-Triple- (not implemented yet) or XML-RDF.

IqRdf underlays a Builder-like approach to specify the RDF-Data by using a internal Ruby DSL. The basic Idea for specifing a triple (subject, predicate, object) is that the predicate is a method call on the subject with the object as parameters:

IqRdf::some_subject.some_predicate(IqRdf::some_object)

The IqRdf namespaces are needed not to mess up the rest of your project due to the heavy use of method_missing in the IqRdf-Library. See the IqRdf::use method for Ruby 1.9 to omit the IqRdf:: prefix.

Ruby example

You can use IqRdf in pure Ruby to produce Strings in a certain RDF Syntax like Turtle or XML:

require 'IqRdf'
document = IqRdf::Document.new('http://www.test.de/')

document.namespaces :skos => 'http://www.w3.org/2008/05/skos#',
  :foaf => 'http://xmlns.com/foaf/0.1/', # A :rdf namespace is added automatically
  :sdmxdimension => {'sdmx-dimension' => 'http://purl.org/linked-data/sdmx/2009/measure#'} # alternative to define namespaces (e.g. if you want to use '-' inside prefix)

document << IqRdf::john_doe.myCustomNote("This is an example", :lang => :en)
# Turtle: :john_doe :myCustomNote "This is an example"@en.

document << IqRdf::john_doe(IqRdf::Foaf::build_uri("Person")).Foaf::name("John Doe")
# Turtle: :john_doe a foaf:Person; foaf:name "John Doe".

document << IqRdf::john_doe.Foaf::knows(IqRdf::jane_doe)
# Turtle: :john_doe foaf:knows :jane_doe.

document.to_turtle
# => "@prefix : <http://www.test.de/>. ..."

Rails example

Include IqRdf to your Ruby on Rails project by adding the following line to your Gemfile (or with Rails 2.x in your config/environment.rb):

gem "iq_rdf"

Add the mime types you want to support to your config/initializers/mime_types.rb file:

Mime::Type.register "application/rdf+xml", :rdf
Mime::Type.register "text/turtle", :ttl
Mime::Type.register "application/n-triples", :nt

Now you can define views in you application. Use the extension .iqrdf for the view files. You can use the extensions .ttl or .rdf in the URL of your request, to force the output to be in Turtle or XML/RDF.

Views

In your views IqRdf gives you a document object you can add your triples to. But first you will have to define your namespaces and the global language if you want to label all String literals in a certain language (as long as there is no other language or :none given).

document.namespaces :default => 'http://data.example.com/', :foaf => 'http://xmlns.com/foaf/0.1/'
document.lang = :en

document << IqRdf::test_subject.test_predicate("test")
# Turtle: :test_subject :test_predicate "test"@en.

document << IqRdf::test_subject.test_predicate("test", :lang => :de)
# Turtle: :test_subject :test_predicate "test"@de.

document << IqRdf::test_subject.test_predicate("test", :lang => :none)
# Turtle: :test_subject :test_predicate "test".

# ...

Use the namespace token :default to mark the default namespace. This has the same effect as specifing the default namespace in IqRdf::Document.new.

Complex RDF definitions

TODO

Copyright (c) 2011 innoQ Deutschland GmbH, released under the Apache License 2.0