Redland RDF Application Framework - Ruby Interface

Installing the Redland Ruby interface

This is built if --with-ruby is given to the configure line, or --with-ruby=ruby1.8 to use a particular Ruby version/program. The standard 'make' at the top level will build it.

You can also compile the Ruby interface by hand as follows:

  cd ruby
  make

  # optional (some tests require test/unit.rb - ships with ruby 1.8.0+)
  make check

To install it system wide do this as root (or maybe via sudo make install):

  root# make install

The Ruby interface was originally written by Dominic Sisneros at the rdf-redland project on RubyForge. The interface here is an update of that with some fixes.

The Ruby interface has been tested with Ruby 1.8.3, 1.8.2, 1.8.1, 1.8. The minimum version is likely 1.8 although older ones may work.

Testing the Redland Ruby interface

The example program provided parses an RDF/XML source file into a model. It should be run with two arguments - the URI of the content (as file:/path/to/content) and the syntax name (say, rdfxml):

   # If installed
   ruby example.ruby file:../data/dc.rdf rdfxml

   # In source tree
   ruby -I. -Ilib example.ruby file:../data/dc.rdf rdfxml

Using the Redland Ruby API

Read the Ruby Doc Redland Ruby Doc API for details of the classes and methods provided wrapping the C API.

The Ruby API is an object-based API reflecting the same structure of the Redland objects with simple mappings between them:

Concept	Redland Class	Ruby Class	Purpose
Resource / Literal	librdf_node	`Redland::Node` `Redland::BNode` `Redland::Literal`	RDF Model & Syntax nodes
Statement / Triple	librdf_statement	`Redland::Statement`	RDF Model & Syntax arcs (statements, triples) [isa Resource]
Model	librdf_model	`Redland::Model`	Set of Statements usually held in one Storage.
Storage	librdf_storage	`Redland::TripleStore` `Redland::FileStore` `Redland::HashStore` `Redland::MemoryStore`	Storage for Models either persistant or in-memory.
Stream	librdf_stream	`Redland::Stream`	Providing sequences of Statements from Parsers, queries.
Parser	librdf_parser	`Redland::Parser`	Syntaxes parsers delivering Stream of Statements or writing to a Model
Query	librdf_query	`Redland::Query`	Querying of an Model delivering a QueryResults
QueryResults	librdf_query_results	`Redland::QueryResults`	Results of applying an Query to a Model giving either variable bindings with Node values or Stream of Statements
Serializer	librdf_serializer	`Redland::Serializer`	Serializes a Model into a syntax such as RDF/XML
Iterator	librdf_iterator		Enumerating lists (of Node) from queries.
URI	librdf_uri	`Redland::Uri`	Provides URIs for Resources, Parsers, ...
World		`Redland::World`	RDF wrapper class handling Redland startup/shutdown
Digest	librdf_digest		Internal content digest class
Hash	librdf_hash		Internal key:value maps class