Using Express sessions

Many of Passport's strategies are based on HTTP sessions. At the moment, our application is just using simple cookies to store user IDs. To use Passport for third-party authentication, we'll need to add session support into our application. Express provides session support in the express-session module. First, we add this to our application:

> npm install express-session --save

We also need somewhere to store session data. Express supports a variety of session stores via additional modules. Redis is well suited to this task and we already have a Redis instance available. We can use the connect-redis module to store sessions in Redis:

> npm install connect-redis --save

We can now create a new configuration module to keep all our session logic in one place. Since this will return middleware, we'll put it in the middleware folder here src/middleware/sessions.js:

'use strict';

const session = require('express-session');

let config...