Check Internet access available in node.js, use book.douban.com to test in this case.

Connectivity.js

// require('dns').resolve('book.douban.com', function(err) {
//   if (err){
//   	console.log('Oops! Cannot access Douban');
//   }
//   else{
//   	console.log('Have Internet Access');
//   }
// });

require('http').get("book.douban.com", function(res) {
	console.log("Got response: " + res.statusCode);
}).on('error', function(e) {
	console.log("Got error: " + e.message);
});