whatsmyip.js

var http = require('http');

exports.query = function(cb) {
  var cbCalled = false;

  http.get({ host: 'jsonip.com' }, function(res) {
    var buffer = '';
    res.setEncoding('utf8');
    res.on('data', function(d) {
      buffer += d;
    });

    res.on('end', function() {
      if (!cbCalled) {
        var i;
        try {
          i = JSON.parse(buffer);
        } catch (e) {
          cbCalled = true;
          cb(e);
          return;
        }

        cbCalled = true;
        cb(null, i.ip);
      }
    });

  }).on('error', function(err) {
    if (!cbCalled) {
      cbCalled = true;
      cb(err);
    }
  });
}