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rdf-virtuoso: Ruby Virtuoso adapter for RDF.rb

The intent of this class is to act as an abstraction for clients wishing to connect and manipulate linked data stored in a Virtuoso Quad store.

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How?

RDF::Virtuoso::Repository subclasses RDF::Repository built on RDF.rb and is the main connection class built on top of APISmith to establish the read and write methods to a Virtuoso store SPARQL endpoint. RDF::Virtuoso::Query subclasses RDF::Query and adds SPARQL 1.1. update methods (insert, delete, aggregates, etc.).

For examples on use, please read: ./spec/repository_spec.rb and ./spec/query_spec.rb

A simple example

This example assumes you have a local installation of Virtoso running at standard port 8890

Setup Repository connection connection with auth

uri        = "http://localhost:8890/sparql"
update_uri = "http://localhost:8890/sparql-auth"
repo       = RDF::Virtuoso::Repository.new(uri, 
                update_uri: update_uri, 
                username: 'admin', 
                password: 'secret', 
                auth_method: 'digest')

:auth_method can be 'digest' or 'basic'. a repository connection without auth requires only uri

INSERT WHERE query example

QUERY = RDF::Virtuoso::Query
graph = RDF::URI.new("http://test.com")
subject = RDF::URI.new("http://subject")

query = QUERY.insert([subject, :p, "object"]).graph(graph).where([subject, :p, :o])
result = repo.insert(query)

A count query example

New prefixes can either extend the RDF::Vocabulary class (best if you want to model yourself:

module RDF
  class FOO < RDF::Vocabulary("http://purl.org/ontology/foo/");end
  class BAR < RDF::Vocabulary("http://bar.net#");end
end

it can then be easily accessed by RDF superclass, eg.

RDF::FOO.Document
=> #<RDF::URI:0x4d273ec(http://purl.org/ontology/foo/Document)> 
RDF::BAR.telescope
=> #<RDF::URI:0x4d294ee(http://bar.net#telescope)>

or you can dynamically add RDF::Vocabulary objects

foo = RDF::Vocabulary.new("http://purl.org/ontology/foo/")

QUERY  = RDF::Virtuoso::Query
graph  = RDF::URI.new("http://test.com")

query  = QUERY.select.where([:s, foo.bar, :o]).count(:s).graph(graph)
result = repo.select(query)

Results will be an array of RDF::Query::Solution that can be accessed by bindings or iterated

count = result.first[:count].to_i

Contributing

This repository uses Git Flow to mange development and release activity. All submissions must be on a feature branch based on the develop branch to ease staging and integration.

  • Do your best to adhere to the existing coding conventions and idioms.
  • Don't use hard tabs, and don't leave trailing whitespace on any line. Before committing, run git diff --check to make sure of this.
  • Do document every method you add using YARD annotations. Read the tutorial or just look at the existing code for examples.
  • Don't touch the .gemspec or VERSION files. If you need to change them, do so on your private branch only.
  • Do note that in order for us to merge any non-trivial changes (as a rule of thumb, additions larger than about 15 lines of code), we need an explicit public domain dedication on record from you, which you will be asked to agree to on the first commit to a repo within the organization. Note that the agreement applies to all repos in the Ruby RDF organization.

License

This is free and unencumbered public domain software. For more information, see https://unlicense.org/ or the accompanying {file:LICENSE} file.