SPARQL.js – A SPARQL 1.1 parser for JavaScript
The SPARQL 1.1 Query Language allows to query datasources of RDF triples.
SPARQL.js translates SPARQL into JSON and back,
so you can parse and build SPARQL queries in your JavaScript applications.
It also contains support for the SPARQL* extension
under the sparqlStar
option.
It fully supports the SPARQL 1.1 specification, including property paths, federation, and updates.
Usage
Library
var SparqlParser = require('sparqljs').Parser;
var parser = new SparqlParser();
var parsedQuery = parser.parse(
'PREFIX foaf: <http://xmlns.com/foaf/0.1/> ' +
'SELECT * { ?mickey foaf:name "Mickey Mouse"@en; foaf:knows ?other. }');
var SparqlGenerator = require('sparqljs').Generator;
var generator = new SparqlGenerator({ });
parsedQuery.variables = ['?mickey'];
var generatedQuery = generator.stringify(parsedQuery);
Set sparqlStar
to true
to allow SPARQL* syntax.
Set pathOnly
to true
to parse SPARQL paths such as foaf:name/foaf:knows
rather than the full SPARQL Algebra.
Validation
By default SPARQL.js throws on queries that are syntactically correct, but not allowed by the spec.
Set skipValidation
to true
to skip validation.
var SparqlParser = require('sparqljs').Parser;
var parser = new SparqlParser({ skipValidation: true });
var parsedQuery = parser.parse(
'select (?x as ?xString)' +
'(count(?y) as ?count)' +
'{ ?x ?y ?z }');
Standalone
$ sparql-to-json --strict query.sparql
Parse SPARQL* syntax by default.
For pure SPARQL 1.1, use the --strict
flag.
Representation
Queries are represented in a JSON structure. The most easy way to get acquainted with this structure is to try the examples in the queries
folder through sparql-to-json
. All examples of the SPARQL 1.1 specification have been included, in case you wonder how a specific syntactical construct is represented.
Here is a simple query in SPARQL:
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>
SELECT ?p ?c WHERE {
?p a dbpedia-owl:Artist.
?p dbpedia-owl:birthPlace ?c.
?c <http://xmlns.com/foaf/0.1/name> "York"@en.
}
And here is the same query in JSON:
{
"queryType": "SELECT",
"variables": [
{
"termType": "Variable",
"value": "p"
},
{
"termType": "Variable",
"value": "c"
}
],
"where": [
{
"type": "bgp",
"triples": [
{
"subject": {
"termType": "Variable",
"value": "p"
},
"predicate": {
"termType": "NamedNode",
"value": "http://www.w3.org/1999/02/22-rdf-syntax-ns#type"
},
"object": {
"termType": "NamedNode",
"value": "http://dbpedia.org/ontology/Artist"
}
},
{
"subject": {
"termType": "Variable",
"value": "p"
},
"predicate": {
"termType": "NamedNode",
"value": "http://dbpedia.org/ontology/birthPlace"
},
"object": {
"termType": "Variable",
"value": "c"
}
},
{
"subject": {
"termType": "Variable",
"value": "c"
},
"predicate": {
"termType": "NamedNode",
"value": "http://xmlns.com/foaf/0.1/name"
},
"object": {
"termType": "Literal",
"value": "York",
"language": "en",
"datatype": {
"termType": "NamedNode",
"value": "http://www.w3.org/1999/02/22-rdf-syntax-ns#langString"
}
}
}
]
}
],
"type": "query",
"prefixes": {
"dbpedia-owl": "http://dbpedia.org/ontology/"
}
}
The representation of triples uses the RDF/JS representation.
Installation
$ [sudo] npm [-g] install sparqljs
License, status and contributions
The SPARQL.js library is copyrighted by Ruben Verborgh
and released under the MIT License.
Contributions are welcome, and bug reports or pull requests are always helpful.
Contributors