Controller proposal

api-controller.js

function ApiController() {
  Controller.call(this);
}

ApiController.prototype = Object.create(Controller.prototype);

ApiController.prototype.error = function (status, message) {
  this.render(status, { 'error': message });
};

ApiController.prototype.render = function (status, data) {
  if (typeof arguments[0] !== 'number') {
    data = arguments[0];
    status = 200;
  }

  var self = this;
  var end = function () {
    data['status'] = status || 200;
    data['ok'] = !data['error'] && (data['status'] < 400);

    self.$response.writeHead(status, self.$headers);
    self.$response.write(JSON.stringify(data));
    self.$response.end();
    this.emit('end');
  };

  if (this.isReady()) {
    end();
  } else {
    this.once('ready', end);
  }
};

base-controller.js

function BaseController(users) {
  ApiController.call(this);

  var current_user_id = this.$session['user_id'];
  if (!current_user_id) {
    return this.error(401, 'Unauthorized');
  }

  this.current_user = users.one(current_user_id);
  this.wait(this.current_user);
}

BaseController.prototype = Object.create(ApiController.prototype);

delayable.js

function Delayable() {
  EventEmitter.call(this);

  this.queue__ = [];

  var self = this;
  process.nextTick(function () {
    if (self.queue__.length === 0) {
      self.emit('ready', self);
    }
  });
}

Delayable.prototype.wait = function (type, source, callback) {
  if (typeof arguments[0] !== 'string') {
    callback = arguments[1];
    source = arguments[0];
    type = 'ready';
  }

  var queue = this.queue__;
  var queue_item = [ source, type ];
  queue.push(queue_item);

  var self = this;
  source.once(type, function () {
    var index = queue.indexOf(queue_item);
    queue.splice(index, 1);

    if (callback) {
      callback.apply(null, arguments);
    }

    if (queue.length === 0) {
      self.emit('ready', self);
    }
  });

  this.emit('delay', source, type);
};

Delayable.prototype.isReady = function () {
  return (this.queue__.length === 0);
};

main.js

var app = framework.createApplication(__dirname + '/app');

app.routes = {
  '/api': {
    'GET /notebooks': 'api/notebook.index',
    'POST /notebooks': 'PUT /notebooks/{@id}',
    'PUT /notebooks/{id}': 'api/notebook.createNotebook',
    'GET /notebooks/{id}': 'api/notebook.showNotebook',
    'POST /notebooks/{id}': 'api/notebook.updateNotebook'
  }
};

app.run();

notebook-controller.js

function NotebookController(notebooks, users) {
  BaseController.call(this, users);

  this.$notebooks = notebooks;
  this.$users = users;
}

NotebookController.prototype = Object.create(BaseController.prototype);

NotebookController.prototype.listNotebooks = function () {
  var current_user = this.current_user;
  var notebooks = this.$notebooks.all(current_user['notebooks']);

  this.wait(notebooks);
  this.render({ 'items': notebooks });
};

NotebookController.prototype.createNotebook = function (id) {
  var values = this.$request.body;
  var current_user = this.current_user;

  var self = this;
  var notebook = this.$notebooks.one(id, []);

  notebook.on('ready', function () {
    if (current_user['notebooks'].contains(id)) {
      return self.updateNotebook(id);
    }
    return self.error(400, 'There is already a notebook with this ID.');
  });

  notebook.on('empty', function () {
    notebook['title'] = values['title'];
    notebook['created_at'] = new Date();
    notebook['updated_at'] = new Date();

    self.$notebooks.save(notebook, function () {
      current_user['notebooks'].push(notebook.id);
      self.$users.save(current_user);

      self.wait(current_user);
      self.wait(notebook);
      self.render({ 'result': notebook });
    });
  });
};

NotebookController.prototype.showNotebook = function (id) {
  var current_user = this.current_user;
  if (!current_user['notebooks'].contains(id)) {
    this.error(403, 'You are not allowed to access this notebook.');
  }

  var self = this;
  var notebook = this.$notebooks.one(id);

  notebook.on('ready', function () {
    self.wait(notebook);
    self.render({ 'result': notebook });
  });

  notebook.on('empty', function () {
    self.error(404, 'Notebook not found');
  });
};