easy-session

easy-session is a session extension and middleware for express and connect with the aim of providing few convenience functions and security features.

Installation

$ npm install easy-session

NB! Breaking changes in v2

• Callbacks are no longer supported. Promises are used instead

Usage

To use easy-session simply require the module and run the .main function with express or connect. This will return the middleware to bind to the stack. It can easily be done with two lines:

const express = require('express');
const session = require('express-session');
const cookieParser = require('cookie-parser');
const easySession = require('easy-session'); // Require the module : line 1

let app = express();

app.use(cookieParser());
app.use(session({
    secret: 'keyboard cat',
    resave: false,
    saveUninitialized: true
}));
app.use(easySession.main(session)); // Bind the module : line 2

Or in Express v3

const express = require('express');
const easySession = require('easy-session'); // Require the module : line 1

let app = express();

app.use(express.cookieParser());
app.use(express.session({secret: 'keyboard cat'});
app.use(easySession.main(express)); // Bind the module : line 2

Options

The middleware supports the following configuration object that can be sent as a second argument to the easySession.main function

{
	ipCheck: {boolean} // Defines if IP must be consistent during the session - defaults to true
	uaCheck: {boolean} // Defines if UA must be consistent during the session - defaults to true
	freshTimeout: {time in ms} // Time since last request still under the maxFreshTimeout
					// when the session is considered fresh - defaults to 5 minutes
	maxFreshTimeout: {time in ms} // Time after which the session is considered stale
					// no matter the activity
	rbac: {object or function} // optional, refer to easy-rbac
}

The IP and UA (User Agent) checks are a method against session hijacking - if the IP or User Agent changes mid-session then it is a good chance that the session has been hijacked. In which case it should be invalidated.

Functions

easy-session adds the following extra functions to the Session object.

login([role='authenticated'],[extend])

Function for logging the user in. Regenerates the session and adds _loggedInAt to the session object. Depending on the configuration also adds _ip and _ua for continuity checks. Session.setRole is called with the specified role If an extend object is added then the key:value pairs are added to the session.

req.session.login()
	.then(() => //here we have a logged in session);

req.session.login({userId: 10})
	.then(() => {
		//here we have a logged in session
		console.log(req.session.userId); // Will print 10;
	});

req.session.login('admin', {userId: 10})
.then(() => {
  //here we have a logged in session
  console.log(req.session.userId); // Will print 10;
});

logout()

Function for logging out the user. Is just a proxy for session regeneration.

req.session.logout()
	.then(() => // Here we have a logged out session);

isGuest()

Function for checking if the user is a guest. Returns true if logged out, false if logged in.

if(!req.session.isGuest()) {
	// Logged in user
}

isLoggedIn([role])

Function for checking if the user is logged in. Will return the opposite of isGuest();

if(req.session.isLoggedIn()) {
	// Logged in user
}

If a role is specified then it will also run Session.hasRole with the given role

isFresh()

Function for checking if the logged in session is fresh or stale. Returns true if fresh, false if stale.

if(req.session.isFresh()) {
	// User has logged in recently - session is fresh
}

setRole(role)

Function for setting a role in the session.

req.session.setRole('admin');

getRole()

Function for returning a role from the session. Will return 'guest' if no role specified.

const role = req.session.getRole();

hasRole(role, [reverse])

Function for validating if the user has the specified role. Accepts string and array input

if(req.session.hasRole('admin')) {
	// User is admin
}

if(req.session.hasRole(['admin', 'user'])) {
	// User is admin or user
}

Also accepts second parameter which reverses the check.

if(req.session.hasRole('admin', true)) {
	// User is not admin
}

if(req.session.hasRole(['admin', 'user'], true)) {
	// User is neither admin or user
}

hasNotRole(role)

Function for validating if a user does not have a specified role. Is equal to hasRole(role, true).

if(req.session.hasNotRole('admin')) {
	// User is not admin
}

if(req.session.hasNotRole(['admin', 'user'])) {
	// User is neither admin or user
}

can(operation, [params])

This function is available only if rbac configuration property was set.

This function uses the getRole function of the session object to invoke easy-rbac. Will return promise.

 app.get('/post/save', function (req, res, next) {
		req.session.can('post:save', {userId: 1, ownerId: 1})
		  .then(accessGranted => {
		    if(accessGranted) {
		      res.send('yes');
		      return;
	      }
	      res.sendStatus(403);
		  })
		  .catch(next);
 });

Middleware

Easy-session provides some middleware for easier session checking

isLoggedIn([errorCallback])

Easy-session also provides an isLoggedIn to check if the user is logged in and handle it accordingly. Usage:

app.get('/restricted', easySession.isLoggedIn(), function (req, res, next) {
	// If the user reaches this then they are logged in.
	// Otherwise they get 401
});

You can also set it before all validation routes

app.all('*', easySession.isLoggedIn());

app.get('/restricted', function (req, res, next) {
	// If the user reaches this then they are logged in.
// Otherwise they get 401
});

You can pass a custom error handler as well

app.all('*', easySession.isLoggedIn(function (req, res, next) {
	// A user that is logged out will reach this.
	// Can handle unauthorized here.
}));

isFresh([errorCallback])

Returns a middleware to check if the user is logged in and the session is fresh.

app.get('/restricted', easySession.isFresh(), function (req, res, next) {
// If the user reaches this then they are logged in and session is fresh
// Otherwise they get 401
});

checkRole(role, [errorCallback])

Returns a middleware to check if the user has a given role.

app.get('/restricted', easySession.checkRole('admin'), function (req, res, next) {
// If the user reaches this then they the 'admin' role
// Otherwise they get 401
});

NB! As of 0.2 it does no longer check if user is logged in

In order to check for both you should use two middlewares together

app.get('/restricted', 
	easySession.isLoggedIn()
	easySession.checkRole('admin'), 
	function (req, res, next) {
    // If the user reaches this then they they are logged in and have the 'admin' role
    // Otherwise they get 401
	});

##can(operation, [params(req, res) => Promise], [errorCallback(req, res, error)])

The easy-session-rbac also exposes a middleware factory can.

If params is a function then it will be invoked and once the promise it returns resolves it will call the rbac with the result as params.

If errorCallback is provided then it will be invoked if check fails, otherwise res.sendStatus(403) is invoked.

// With no params
app.get('/middleware/post/delete', esRbac.can('post:delete'), function (req, res, next) {
  res.send('yes');
});

// With params function
app.get(
  '/middleware/post/save/:id', 
  esRbac.can('post:save', async (req, res) => ({userId: 1, ownerId: +req.params.id})), 
  function (req, res, next) {
    res.send('yes');
  }
);

// With errorCallback
app.get(
  '/middleware/post/delete', 
  esRbac.can('post:delete', {}, function (req, res, err) {
    console.log(err);
    res.send('You are not authorized');
  }), 
  function (req, res, next) {
    res.send('yes');
  }
);

Changelog

• v2.0.2 - account for usage of req.session.destroy()

License

The MIT License (MIT) Copyright (c) 2014 Karl Düüna

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.