Raptor RDF Extension for RDF.rb

This is an RDF.rb extension that adds support for parsing/serializing NTriples, RDF/XML, Turtle, RDFa, and Graphviz data using the Raptor RDF Parser library.

Features

• Uses the fast Raptor C library.
• Parses and serializes RDF data from/into the NTriples, RDF/XML, and Turtle formats.
• Extracts RDF statements from XHTML+RDFa documents.
• Serializes RDF statements into Graphviz format.
• Provides serialization format auto-detection for RDF/XML, Turtle and RDFa.
• Compatible with any operating system supported by Raptor and Ruby.
• Compatible with MRI >= 2.6, JRuby and Rubinius.

Examples

require 'rdf/raptor'

Ensuring Raptor is installed and obtaining the version number

RDF::Raptor.available?         #=> true
RDF::Raptor.version            #=> "3.2.0"

Parsing RDF statements from an NTriples file

RDF::Reader.open("http://datagraph.org/jhacker/foaf.nt") do |reader|
  reader.each_statement do |statement|
    puts statement.inspect
  end
end

Parsing RDF statements from an RDF/XML file

RDF::Reader.open("http://datagraph.org/jhacker/foaf.rdf") do |reader|
  reader.each_statement do |statement|
    puts statement.inspect
  end
end

Parsing RDF statements from a Turtle file

RDF::Reader.open("http://datagraph.org/jhacker/foaf.ttl") do |reader|
  reader.each_statement do |statement|
    puts statement.inspect
  end
end

Extracting RDF statements from an HTML+RDFa document

RDF::Reader.open(url = "http://bblfish.net/", format: :rdfa, base_uri: url) do |reader|
  reader.each_statement do |statement|
    puts statement.inspect
  end
end

Serializing RDF statements into an RDF/XML file

data = RDF::Repository.load("http://datagraph.org/jhacker/foaf.nt")

RDF::Writer.open("output.rdf") do |writer|
  data.each_statement do |statement|
    writer << statement
  end
end

Serializing RDF statements into a Turtle file

data = RDF::Repository.load("http://datagraph.org/jhacker/foaf.nt")

RDF::Writer.open("output.ttl") do |writer|
  data.each_statement do |statement|
    writer << statement
  end
end

Obtaining the NTriples format specification class

RDF::Format.for(:ntriples)      #=> RDF::Raptor::NTriples::Format
RDF::Format.for("input.nt")
RDF::Format.for(file_name:      "input.nt")
RDF::Format.for(file_extension: "nt")
RDF::Format.for(content_type:   "application/n-triples")

Obtaining the RDF/XML format specification class

RDF::Format.for(:rdfxml)       #=> RDF::Raptor::RDFXML::Format
RDF::Format.for("input.rdf")
RDF::Format.for(file_name:      "input.rdf")
RDF::Format.for(file_extension: "rdf")
RDF::Format.for(content_type:   "application/rdf+xml")

Obtaining the Turtle format specification class

RDF::Format.for(:turtle)       #=> RDF::Raptor::Turtle::Format
RDF::Format.for("input.ttl")
RDF::Format.for(file_name:      "input.ttl")
RDF::Format.for(file_extension: "ttl")
RDF::Format.for(content_type:   "text/turtle")

Obtaining the RDFa format specification class

RDF::Format.for(:rdfa)         #=> RDF::Raptor::RDFa::Format
RDF::Format.for("input.html")
RDF::Format.for(file_name:      "input.html")
RDF::Format.for(file_extension: "html")
RDF::Format.for(content_type:   "application/xhtml+xml")

Obtaining the Graphviz format specification class

RDF::Format.for(:graphviz)     #=> RDF::Raptor::Graphviz::Format
RDF::Format.for("output.dot")
RDF::Format.for(file_name:      "output.dot")
RDF::Format.for(file_extension: "")
RDF::Format.for(content_type:   "text/vnd.graphviz")

Documentation

https://ruby-rdf.github.io/rdf-raptor/

• {RDF::Raptor}
  • {RDF::Raptor::NTriples}
  • {RDF::Raptor::Turtle}
  • {RDF::Raptor::RDFXML}
  • {RDF::Raptor::RDFa}
  • {RDF::Raptor::Graphviz}

Dependencies

• RDF.rb (~> 3.2)
• FFI (~> 1.15)
• Raptor (>= 2.0), the libraptor library or the rapper binary

Installation

The recommended installation method is via RubyGems. To install the latest official release of the RDF::Raptor gem, do:

% [sudo] gem install rdf-raptor

To install the required Raptor command-line tools themselves, look for a raptor or raptor-utils package in your platform's package management system. For your convenience, here follow installation instructions for the Mac and the most common Linux and BSD distributions:

% [sudo] port install raptor             # Mac OS X with MacPorts
% [sudo] fink install raptor-bin         # Mac OS X with Fink
% brew install raptor                    # Mac OS X with Homebrew
% [sudo] aptitude install raptor-utils   # Ubuntu / Debian with aptitude
% [sudo] apt-get install libraptor2-0    # Ubuntu / Debian with apt-get
% [sudo] yum install raptor2             # Fedora / CentOS / RHEL
% [sudo] zypper install raptor           # openSUSE
% [sudo] emerge raptor                   # Gentoo Linux
% [sudo] pacman -S raptor                # Arch Linux
% [sudo] pkg_add -r raptor               # FreeBSD
% [sudo] pkg_add raptor                  # OpenBSD / NetBSD

If the libraptor2 library is in the standard library search path, and the rapper command is in the standard command search path, all should be well and work fine out of the box. However, if either is in a non-standard location, be sure to set the RDF_RAPTOR_LIBPATH and/or RDF_RAPTOR_BINPATH environment variables appropriately before requiring rdf/raptor.

Download

To get a local working copy of the development repository, do:

% git clone git@github.com:ruby-rdf/rdf-raptor.git

Alternatively, download the latest development version as a tarball as follows:

% wget https://github.com/ruby-rdf/rdf-raptor/tarball/master

Mailing List

• https://lists.w3.org/Archives/Public/public-rdf-ruby/

Authors

• Arto Bendiken - https://ar.to/
• John Fieber - https://github.com/jfieber

Contributors

• Ben Lavender - https://bhuga.net/
• David Butler - https://github.com/dwbutler
• Gregg Kellogg - https://greggkellogg.net/

License

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