Authentication with Express.js

Many web applications require a login system. Often, users of a website have different privileges, and to ascertain which resources they're able to access, they must first be identified via authentication.

This is typically achieved by setting up a session, which is a temporary information exchange between a user and a device. In this recipe, we're going to implement an authentication layer for an Express.js server.

Getting ready

We must first start by scaffolding an Express.js web server for the recipe:

Important Note

For a more detailed introduction to Express.js, refer to the Building web applications with Express.js recipe in Chapter 6, Exploring Node.js Web Frameworks.

1. First, let's create a project directory to work in and initialize the project with npm. We'll also create some files and subdirectories that we'll use later in the recipe:

   $ mkdir express-auth
   $ cd express-auth
   $ npm init --yes
   $ mkdir...