read-xml/lib/findEncoding.js

Read a xml file respecting its encoding information

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _debug = require('debug');

var _debug2 = _interopRequireDefault(_debug);

var _once = require('once');

var _once2 = _interopRequireDefault(_once);

var _parseAttributes = require('parse-attributes');

var _parseAttributes2 = _interopRequireDefault(_parseAttributes);

var _sax = require('sax');

var _sax2 = _interopRequireDefault(_sax);

var _package = require('../package.json');

var _package2 = _interopRequireDefault(_package);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var debugMe = (0, _debug2.default)(_package2.default.name + ':parse-xml');

function findEncodingAttr(xmlDeclaration) {
  var indexEncoding = void 0,
      indexUpperEncoding = void 0,
      propToUse = void 0;

  // look for the last encoding attr
  indexEncoding = xmlDeclaration.lastIndexOf('encoding');
  indexUpperEncoding = xmlDeclaration.lastIndexOf('ENCODING');
  propToUse = indexEncoding > indexUpperEncoding ? 'encoding' : 'ENCODING';

  return (0, _parseAttributes2.default)(xmlDeclaration)[propToUse];
}

function findEncodingInXMLBuffer(buf, defaultEncoding, cb) {
  var xmlParser = _sax2.default.parser(false, {
    trim: false,
    normalize: false,
    lowercase: false,
    strictEntities: false
  });

  var xmlContent = buf.toString();
  var done = (0, _once2.default)(function (err, encoding) {
    return cb(err, encoding);
  });

  xmlParser.onerror = function (err) {
    debugMe('xml parser error (parsing will be continued):', err.message);
    xmlParser.error = null;
    xmlParser.resume();
  };

  xmlParser.onopentag = function (node) {
    debugMe('open tag found:', node.name);

    if (done.called) {
      return;
    }

    debugMe('encoding to be used:', defaultEncoding);
    done(null, defaultEncoding);
  };

  xmlParser.onprocessinginstruction = function (instruction) {
    debugMe('processing instruction found:', instruction.name);

    if (done.called) {
      return;
    }

    if (instruction.name.toLowerCase() === 'xml') {
      var xmlEncoding = findEncodingAttr(instruction.body);
      debugMe('detected encoding in xml:', xmlEncoding);
      xmlEncoding = xmlEncoding || defaultEncoding;
      debugMe('encoding to be used:', xmlEncoding);
      done(null, xmlEncoding);
    }
  };

  xmlParser.onend = function () {
    debugMe('xml parsing has ended..');

    if (done.called) {
      return;
    }

    debugMe('no tag or xml declaration was found..');
    done(null, undefined);
  };

  debugMe('parsing chunk:', xmlContent);
  xmlParser.write(xmlContent).close();
}

exports.default = findEncodingInXMLBuffer;
module.exports = exports['default'];