dolar-blue/lib/sources/LaNacion.js

dolar-blue ==========

var http = require('http');

// Public API for this package
exports.getData = function(cb) {

  var options = {
    name: 'LaNacion',
    host: 'contenidos.lanacion.com.ar',
    path: '/json/dolar'
  };

  var req = http.request(options, function(res) {
    var str = '';

    res.on('data', function(chunk) {
      str += chunk;
    });

    res.on('end', function() {

      // Set up return object
      var ret = {};
      ret.date = new Date();
      ret.source = {
        name: options.name,
        uri: 'http://' + options.host + options.path
      };

      // Parse response from LaNacion
      try {

        // LaNacion uses JSONP, strip the function wrapper to get JSON
        str = str.substr(19, str.length - 19 - 2);
        ret.data = JSON.parse(str);
      } catch (err) {
        return cb('Bad JSON from ' + options.host + options.path + ':' + err + '\n' + str);
      }

      // Format response from LaNacion into decimal values
      if (ret.data.CasaCambioVentaValue && ret.data.CasaCambioCompraValue) {
        var ventaDecimal = parseFloat(ret.data.CasaCambioVentaValue.replace(/,/, '.')),
          compraDecimal = parseFloat(ret.data.CasaCambioCompraValue.replace(/,/, '.'));

        if (isNaN(ventaDecimal) || isNaN(compraDecimal)) {
          cb('rate is NaN');
        } else {
          ret.rates = {
            buy: compraDecimal,
            sell: ventaDecimal,
            source: options.name,
            date: new Date(ret.data.Date)
          };

          cb(null, ret);
        }
      } else {
        cb('Unexpected response from ' + options.host + options.path);
      }
    });
  });

  req.end();

  req.on('error', function(e) {
    cb(e);
  });

};