jairo-parser

Simplified RDF/XML parser

Jairo Parser is built on the powerful rdf parser library rdf-ext. You can use it inside Node.js application. Jairo Parser gives you a simpler way to parse RDF/XML by passing output into a simplified JSON object (Jairo Object ).

Installation

npm install jairo-parser

Usage

Parsing RDF/XML data from a string

 
var jairo = require('jairo-parser');
 
var prefixesOfInterest = [
        { 'prefix' : 'rdf' , 'uri' : 'http://www.w3.org/1999/02/22-rdf-syntax-ns##' },
        { 'prefix' : 'dcterms' , 'uri' : 'http://purl.org/dc/terms/' },
        { 'prefix' : 'foaf' , 'uri' : 'http://xmlns.com/foaf/0.1/' }
    ];
 
var rdf =  
'<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns##" ' + 
' xmlns:dcterms="http://purl.org/dc/terms/" ' + 
' xmlns:foaf="http://xmlns.com/foaf/0.1/"> ' + 
' <rdf:Description rdf:about="http://example.org/123"> ' + 
'  <dcterms:creator> ' + 
'   <foaf:Person rdf:about="http://example.org/person45"> ' + 
'    <rdf:value>John Smith</rdf:value> ' + 
'    <foaf:phone rdf:resource="tel:[phone]"/> ' + 
'   </foaf:Person> ' + 
'  </dcterms:creator>  ' + 
' </rdf:Description> ' + 
'</rdf:RDF>';
 
jairo.parse( 'rdfxml' , rdf , prefixesOfInterest , function( parsedData ){
    console.log( parsedData );
    jairo.printHumanReadbleResult( parsedData );
});
 

Parsing RDF/XML data from a file

File: test.rdf

<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns##" 
 xmlns:dcterms="http://purl.org/dc/terms/" 
 xmlns:foaf="http://xmlns.com/foaf/0.1/">  
 <rdf:Description rdf:about="http://example.org/123"> 
  <dcterms:creator> 
   <foaf:Person rdf:about="http://example.org/person45"> 
    <rdf:value>John Smith</rdf:value> 
    <foaf:phone rdf:resource="tel:[phone]"/> 
   </foaf:Person> 
  </dcterms:creator>  
 </rdf:Description>  
</rdf:RDF>

Load RDF/XML data from a file

var jairo = require('jairo-parser');
var fs = require('fs');
 
var prefixesOfInterest = [
        { 'prefix' : 'rdf' , 'uri' : 'http://www.w3.org/1999/02/22-rdf-syntax-ns##' },
        { 'prefix' : 'dcterms' , 'uri' : 'http://purl.org/dc/terms/' },
        { 'prefix' : 'foaf' , 'uri' : 'http://xmlns.com/foaf/0.1/' }
    ];
 
fs.readFile( 'test.rdf', 'utf8', function (err, fileContent) {
    if (err) throw err;
    jairo.parse( 'rdfxml' , fileContent , prefixesOfInterest , function( parsedData ){
        console.log( parsedData );
        jairo.printHumanReadbleResult( parsedData );
    });
});
 

Output of console.log( parsedData );

Output of jairo.printHumanReadbleResult( parsedData );

Iterating over Jairo objects

Based on the example code, you can iterate triples by following code.

    jairo.parse( 'rdfxml' , rdf , prefixesOfInterest , function( parsedData ){
        console.log( parsedData );
 
        for (var i = 0; i < parsedData.triples.length; i++) {
            // Get properties on each triple
        };
 
        for (var prop in parsedData.prefixesParsed ) {
            // List all parsed prefixes 
        }
 
        for (var prop in parsedData.prefixesParsedStat ) {
            // Count number of prefixes
        }
 
    });  

Access each triple

    for (var i = 0; i < parsedData.triples.length; i++) {
        var triple = parsedData.triples[i];
        console.log('subject_uri=' + triple.subject_uri);
        console.log('subject_qn=' + triple.subject_qn);
        console.log('predicate_uri=' + triple.predicate_uri);
        console.log('predicate_qn=' + triple.predicate_qn);
        console.log('object_uri=' + triple.object_uri);
        console.log('object_qn=' + triple.object_qn);
        console.log('subject_uri=' + triple.subject_uri);
        console.log('subject_uri=' + triple.subject_uri);
    };

Output

    subject_uri=<http://example.org/123>
    subject_qn=123
    predicate_uri=<http://purl.org/dc/terms/creator>
    predicate_qn=dcterms:creator
    object_uri=<http://example.org/person45>
    object_qn=person45
 
    subject_uri=<http://example.org/person45>
    subject_qn=person45
    predicate_uri=<http://www.w3.org/1999/02/22-rdf-syntax-ns##type>
    predicate_qn=rdf:type
    object_uri=<http://xmlns.com/foaf/0.1/Person>
    object_qn=Person
 
    subject_uri=<http://example.org/person45>
    subject_qn=person45
    predicate_uri=<http://www.w3.org/1999/02/22-rdf-syntax-ns##value>
    predicate_qn=rdf:value
    object_uri=John Smith
    object_qn=John Smith
 
    subject_uri=<http://example.org/person45>
    subject_qn=person45
    predicate_uri=<http://xmlns.com/foaf/0.1/phone>
    predicate_qn=foaf:phone
    object_uri=tel:[phone]
    object_qn=tel:[phone]

List all parsed prefixes

    for (var prop in parsedData.prefixesParsed ) {
        console.log('prefix=' + prop + ' uri=' + parsedData.prefixesParsed[prop]);
    }

Output

    prefix=dcterms:creator uri=http://purl.org/dc/terms/
    prefix=rdf:type uri=http://www.w3.org/1999/02/22-rdf-syntax-ns##
    prefix=rdf:value uri=http://www.w3.org/1999/02/22-rdf-syntax-ns##
    prefix=foaf:phone uri=http://xmlns.com/foaf/0.1/

Count number of prefixes

    for (var prop in parsedData.prefixesParsedStat ) {
        console.log('prefix=' + prop + ' count=' + parsedData.prefixesParsedStat[prop]);
    }

Output

    prefix=dcterms:creator count=1
    prefix=rdf:type count=1
    prefix=rdf:value count=1
    prefix=foaf:phone count=1