rdflib.js RDF API Example

rdf_example.js

/**
 * rdflib.js with node.js -- basic RDF API example.
 * @author ckristo
 */

var fs = require('fs');
var $rdf = require('rdflib');

FOAF = $rdf.Namespace('http://xmlns.com/foaf/0.1/');
XSD  = $rdf.Namespace('http://www.w3.org/2001/XMLSchema#');

// - create an empty store
var kb = new $rdf.IndexedFormula();

// - load RDF file
fs.readFile('foaf.rdf', function (err, data) {
    if (err) { /* error handling */ }

    // NOTE: to get rdflib.js' RDF/XML parser to work with node.js,
    // see https://github.com/linkeddata/rdflib.js/issues/47

    // - parse RDF/XML file
    $rdf.parse(data.toString(), kb, 'foaf.rdf', 'application/rdf+xml', function(err, kb) {
        if (err) { /* error handling */ }

        var me = kb.sym('http://kindl.io/christoph/foaf.rdf#me');

        // - add new properties
        kb.add(me, FOAF('mbox'), kb.sym('mailto:e0828633@student.tuwien.ac.at'));
        kb.add(me, FOAF('nick'), 'ckristo');

        // - alter existing statement
        kb.removeMany(me, FOAF('age'));
        kb.add(me, FOAF('age'), kb.literal(25, null, XSD('integer')));

        // - find some existing statements and iterate over them
        var statements = kb.statementsMatching(me, FOAF('mbox'));
        statements.forEach(function(statement) {
            console.log(statement.object.uri);
        });

        // - delete some statements
        kb.removeMany(me, FOAF('mbox'));

        // - print modified RDF document
        $rdf.serialize(undefined, kb, undefined, 'application/rdf+xml', function(err, str) {
            console.log(str);
        });
    });
});