Start of a simple promise-based HTTP client, based on Q-IO and inspired by SuperAgent

client.js

var http = require('q-io/http');
var BufferStream = require('q-io/buffer-stream');

// Response

function Response(promise) {
  this.promise = promise;

  this.status = this.promise.get('status');

  this.buffer = this.promise.then(function (response) {
    return response.body.read();
  });

  this.body = this.buffer.then(function (buffer) {
    return JSON.parse(buffer.toString());
  });
}

// Client

function Client(baseUrl) {
  this.baseUrl = baseUrl;
}

// Assumes content type JSON for now
Client.prototype.post = function (path, bodyObject) {
  var url = this.baseUrl + path;

  var request = http.normalizeRequest(url);
  request.method = 'POST';
  request.headers['content-type'] = 'application/json';

  var json = JSON.stringify(bodyObject);
  request.body = BufferStream(new Buffer(json));

  var promise = http.request(request);
  return new Response(promise);
}

// exports

module.exports = Client;

test.js

// Example of how this could be used in a test using Mocha, Chai, mocha-as-promised and chai-as-promised

var client = new Client('http://localhost:5000');

describe('User creation', function () {
  describe('when an email is submitted', function () {
    var response;

    before(function () {
      response = client.post('/users', {email: 'jason@jasoncrawford.org'});
    });

    it('should return 201 Created', function () {
      return expect(response.status).eventually.equal(201);
    });

    it('should return a user object with an ID', function () {
      return expect(response.body.get('_id')).eventually.ok;
    });

    it('should return a user object with the same email given', function () {
      return expect(response.body.get('email')).eventually.equal('jason@jasoncrawford.org');
    });
  });
});