How does node 0.11 get the body of the post request

  node.js, question

How does node 0.11 get the body of the post request
http.createServer(function(req, res){
});

Req has no rawBody nor body attribute.

Thank you for your help. It has been solved. Without using the express library, the native node can only use the body to obtain post request.
http.createServer(function(req, res){
req.on(‘data’,function(data){
});
}).listen(port);