A pure Dart package for working with RDF (resource description framework).
- Create triple instances (with data types)
- Create a graph to store triples without duplicates
- Find triples based on criteria
- Export graph to turtle
ttl
format (default) - Bind long namespace with customized shortened name for readability
- Include reserved vocabulary of OWL 2
- Parse turtle format string effectively and store triples in the graph in memory
Refer to the code example below, or go to /example
to find out more!
# create a dart project for testing
dart create test_rdflib
cd test_rdflib
# install rdflib as the dependency with dart pub add
dart pub add rdflib
# copy the following code examples to ~/bin/test_rdflib.dart
# run the file with dart
dart run
Head over to our GitHub repo to check out more examples!
The following code snippet shows how to:
- Create a
Graph
instance; - Create and store
triple
s with different data types; - Find entities based on customized criteria;
- Bind shorted string to long
namespace
;
import 'package:rdflib/rdflib.dart';
main() {
// the following example is modified from <https://rdflib.readthedocs.io/en/stable/gettingstarted.html#a-more-extensive-example>
// Initialize a Graph
Graph g = Graph();
// Create a new URIRef instance for a person
final donna = URIRef('http://example.org/donna');
// Add triples to the Graph using [Graph.addTriplesToGroups] method
g.addTripleToGroups(donna, RDF.type, FOAF.Person);
g.addTripleToGroups(donna, FOAF.nick, Literal('donna', lang: 'en'));
g.addTripleToGroups(donna, FOAF.name, Literal('Donna Fales'));
g.addTripleToGroups(donna, FOAF.mbox, URIRef('mailto:donna@example.org'));
// Adding a duplicate triple should be ignored
g.addTripleToGroups(donna, FOAF.mbox, URIRef('mailto:donna@example.org'));
// Create another URIRef instance
final ed = URIRef('http://example.org/edward');
// Add triples to the Graph
g.addTripleToGroups(ed, RDF.type, FOAF.Person);
g.addTripleToGroups(ed, FOAF.nick, Literal('ed', datatype: XSD.string));
g.addTripleToGroups(ed, FOAF.name, Literal('Edward Scissorhands'));
g.addTripleToGroups(
ed, FOAF.mbox, Literal('mailto:ed@example.org', datatype: XSD.anyURI));
// Bind the long namespace to shorter string for better readability
g.bind('example', Namespace(ns: 'http://example.org/'));
// Serialize the Graph to the standard turtle format, and the result is stored
// in [Graph.serializedString]
g.serialize(format: 'ttl', abbr: 'short');
print('-------\nSerialized content:\n${g.serializedString}');
// Print out every added triple in the graph by iterating through the set
print('-------\nTriples updated in the graph:');
for (Triple t in g.triples) {
print(t);
}
// Print out each person's mailbox value
print('-------\nMailboxes:');
for (var sub in g.subjects(a, FOAF.Person)) {
for (var mbox in g.objects(sub, FOAF.mbox)) {
print('${sub}\'s mailbox: ${mbox.value}');
}
}
}
import 'package:rdflib/rdflib.dart';
main() {
// Initialize a Graph
Graph g = Graph();
// Define namespaces for later use
Namespace shData = Namespace(ns: 'http://silo.net.au/data/SOLID-Health#');
Namespace shOnto =
Namespace(ns: 'http://sii.cecs.anu.edu.au/onto/SOLID-Health#');
// Create a subject
URIRef newAssessTab = shData.withAttr('AssessmentTab-p43623-20220727T120913');
// Add the entity to the Graph, equivalent to
// g.addTripleToGroups(newAssessTab, rdf.typ, owl:NamedIndividual)
g.addNamedIndividualToGroups(newAssessTab);
// Add using a Triple type
Triple t1 = Triple(
sub: newAssessTab, pre: RDF.type, obj: shOnto.withAttr('AssessmentTab'));
g.addTripleToGroups(t1.sub, t1.pre, t1.obj);
// Add directly using sub, pre, and obj
g.addTripleToGroups(
newAssessTab, shData.withAttr('asthmaControl'), 'Poor Control');
g.addTripleToGroups(
newAssessTab, shOnto.withAttr('diastolicBloodPressure'), '75');
g.addTripleToGroups(
newAssessTab, shOnto.withAttr('systolicBloodPressure'), Literal('125.0'));
URIRef newSeeAndDoTab = shData.withAttr('SeeAndDoTab-p43623-20220727T120913');
URIRef newSeeAndDoOption =
shData.withAttr('SeeAndDoOption-p43623-20220727T120913-fitnessDrive');
g.addNamedIndividualToGroups(newSeeAndDoTab);
g.addNamedIndividualToGroups(newSeeAndDoOption);
// Link two triple individuals by a relation
g.addObjectProperty(
newSeeAndDoTab, shOnto.withAttr('hasSeeAndDoOption'), newSeeAndDoOption);
// Bind to shorter abbreviations for readability
g.bind('sh-data', shData);
g.bind('sh-onto', shOnto);
// Serialize the graph for output
g.serialize(format: 'ttl', abbr: 'short');
print(g.serializedString);
}
import 'dart:io';
import 'package:rdflib/rdflib.dart';
main() async {
String filePath = 'example/sample_ttl_1.ttl';
// Read file content to a local String
String fileContents = await File(filePath).readAsStringSync();
print('-------Original file-------\n$fileContents');
// create a graph to read turtle file and store info
Graph g = Graph();
// Parse with the new method [Graph.parseTurtle] instead of [Graph.parse] (deprecated)
g.parseTurtle(fileContents);
// Serialize the Graph for output
g.serialize(format: 'ttl', abbr: 'short');
print('-------Serialized String--------\n${g.serializedString}');
// Print out full format of triples (will use shorthand in serialization/export)
print('--------All triples in the graph-------');
for (Triple t in g.triples) {
print(t);
}
}
import 'dart:io';
import 'package:http/http.dart' as http;
import 'package:rdflib/rdflib.dart';
main() async {
// https://github.com/anusii/rdflib/blob/main/example/sample_acl_1.acl
// https://raw.githubusercontent.com/anusii/rdflib/main/example/sample_acl_1.acl
var url = Uri.https('raw.githubusercontent.com',
'anusii/rdflib/main/example/sample_acl_1.acl');
// Get the contents of the acl file
var res = await http.get(url);
String aclContents = res.body;
print('-------Original ACL Contents-------\n${res.body}\n');
// Initialize a Graph to store all the info
Graph g = Graph();
// Parse the contents and update the triples
g.parseTurtle(aclContents);
g.serialize(format: 'ttl', abbr: 'short');
print('-------Serialized ACL Contents------\n${g.serializedString}\n');
// Add 'zack' to the ACL file
g.addTripleToGroups('<#zack>', a, 'acl:Authorization');
// Specify which document/fold
g.addTripleToGroups('<#zack>', 'acl:accessTo', '<./README>');
// Specify the target by its webID card
g.addTripleToGroups('<#zack>', 'acl:agent',
'<https://solid.dev.yarrabah.net/zack-collins/profile/card#me>');
// Grant him access to Read only
g.addTripleToGroups('<#zack>', 'acl:mode', 'acl:Read');
// Need to serialize before exporting
g.serialize(format: 'ttl', abbr: 'short');
print('-------Serialized ACL Contents (New)------\n${g.serializedString}\n');
}
Make a pull request on our GitHub repo!
- This
rdflib
dart package is modelled on the RDFLib. - The parser is written with package dart-petitparser