This is how I handle converting the Node.JS http library over to a promise using Bluebird. This works for both GET and POST.

httpPromise.js

var http = require('http'),
    Promise = require('bluebird');
var PromiseRequest = Promise.method(function(data){
    return new Promise(function(resolve,reject){
        var request = http.request(data.options, function(res){
            var response = null;
            res.setEncoding('utf8');
            res.on('data', function (chunk) {
                console.log('Response: ' + chunk);
                if(response)
                    response += chunk;
                else
                    response = chunk;
            });
            res.on('end', function(){
                resolve(JSON.parse(response));
            });
        }).on("error",reject);
        if(data.postData) {
          request.write(data.postData);
        }
        request.end();
    });
});

// Useage
function addNode(node) {
  var postData = JSON.stringify({
    // I am doing this hack because the json var
    // is supposed to be a string so I am worried
    // about escaping chars
    json : JSON.stringify(node)
  });
  var options = {
    host: HOST,
    port: PORT,
    method: "POST",
    path: PATH,
    headers: {
        "Content-Type": "application/json",
        "Content-Length": Buffer.byteLength(postData),
        "Authorization": auth
    }
  };
  return PromiseRequest({
    options : options,
    postData: postData
  })
}

function getLabels() {
  var options = {
    host: HOST,
    port: PORT,
    method: "GET",
    path: PATH,
    headers: {
      "Authorization": auth
    }
  };
  return PromiseRequest({
    options : options
  })
}