access-control.js

//components/access-control/access-control.js

var isBrowser = require('is-browser');

var userRoles = exports.userRoles = {
  anon: 1,
  user: 2,
  admin: 4
};

var accessLevels = exports.accessLevels = {
  any: userRoles.anon | userRoles.user | userRoles.admin,
  anon: userRoles.anon,
  user: userRoles.user | userRoles.admin,
  admin: userRoles.admin
};

if(isBrowser) {
  var AccessControl = angular.module('spotlight.access-control', ['ngCookies']).factory('Auth', ['$http', '$rootScope', '$cookieStore', 
  function($http, $rootScope, $cookieStore) {
    var currentUser = $cookieStore.get('user') || { username: '', role: userRoles.anon };
    $cookieStore.remove('user');

    return {
      authorize: function(accessLevel, role) {
        if(role === undefined)
          role = currentUser.role;
        return accessLevel & role;
      },
      
      isLoggedIn: function(user) {
        if(user === undefined)
          user = currentUser;
        return user.role & (userRoles.admin | userRoles.user);
      },
      accessLevels: accessLevels,
      userRoles: userRoles,
      user: currentUser
    };
  }]);

  AccessControl.directive('accessLevel', ['Auth', function(Auth) {
    return {
      restrict: 'A',
      link: function($scope, element, attrs) {
        var prevDisp = element.css('display'),
            userRole,
            accesslevel;

        $scope.currentUser = Auth.user;
        $scope.$watch('currentUser', function(user) {
          if(user.role)
            userRole = user.role;
          updateCSS();
        }, true);

        attrs.$observe('accessLevel', function(al) {
          if(al) accessLevel = Auth.accessLevels[al];
        });
        function updateCSS() {
          if(userRole && accessLevel) {
            if(!Auth.authorize(accessLevel, userRole))
              element.css('display', 'none');
            else
              element.css('display', prevDisp);
          }
        }
      }
    };
  }]);
}

app.js

AccessControl = require('access-control');

app.get('/*', function(req, res, next) {
  var role = AccessControl.userRoles.anon, username = '';
  if(req.user) {
    role = req.user.role();
    username = req.user.username()
  }
  res.cookie('user', JSON.stringify({
    username: username,
    role: role
  }));
  res.render('./lib/pages/site-wide/layout.jade');
})

user-model.js

// User-model/user-model.js
var modella = require('modella'),
    UserRoles = require('access-control').userRoles;
    
var User = module.exports = modella('User')
    .attr('username' , { required: true, unique: true, type: 'string' } )
    .attr('role'    ,  { required: true, type: 'number', default: UserRoles.User } )