link-rdflib/lib/serialize.js

an RDF library for node.js, patched for speed.

"use strict";

module.exports = serialize;

var convert = require('./convert');

var Serializer = require('./serializer');
/**
 * Serialize to the appropriate format
 * @@ Currently NQuads and JSON/LD are deal with extrelemently inefficiently
 * through mutiple conversions.
 */


function serialize(target, kb, base, contentType, callback, options) {
  base = base || target.uri;
  options = options || {};
  contentType = contentType || 'text/turtle'; // text/n3 if complex?

  var documentString = null;

  try {
    var sz = Serializer(kb);
    if (options.flags) sz.setFlags(options.flags);
    var newSts = kb.statementsMatching(undefined, undefined, undefined, target);
    var n3String;
    sz.suggestNamespaces(kb.namespaces);
    sz.setBase(base);

    switch (contentType) {
      case 'application/rdf+xml':
        documentString = sz.statementsToXML(newSts);
        return executeCallback(null, documentString);

      case 'text/n3':
      case 'application/n3':
        // Legacy
        documentString = sz.statementsToN3(newSts);
        return executeCallback(null, documentString);

      case 'text/turtle':
      case 'application/x-turtle':
        // Legacy
        sz.setFlags('si'); // Suppress = for sameAs and => for implies

        documentString = sz.statementsToN3(newSts);
        return executeCallback(null, documentString);

      case 'application/n-triples':
        sz.setFlags('deinprstux'); // Suppress nice parts of N3 to make ntriples

        documentString = sz.statementsToNTriples(newSts);
        return executeCallback(null, documentString);

      case 'application/ld+json':
        sz.setFlags('deinprstux'); // Use adapters to connect to incmpatible parser

        n3String = sz.statementsToNTriples(newSts); // n3String = sz.statementsToN3(newSts)

        convert.convertToJson(n3String, callback);
        break;

      case 'application/n-quads':
      case 'application/nquads':
        // @@@ just outpout the quads? Does not work for collections
        sz.setFlags('deinprstux q'); // Suppress nice parts of N3 to make ntriples

        documentString = sz.statementsToNTriples(newSts); // q in flag means actually quads

        return executeCallback(null, documentString); // n3String = sz.statementsToN3(newSts)
        // documentString = convert.convertToNQuads(n3String, callback)

        break;

      default:
        throw new Error('Serialize: Content-type ' + contentType + ' not supported for data write.');
    }
  } catch (err) {
    if (callback) {
      return callback(err);
    }

    throw err; // Don't hide problems from caller in sync mode
  }

  function executeCallback(err, result) {
    if (callback) {
      callback(err, result);
      return;
    } else {
      return result;
    }
  }
}