Authentication with Fastify

Many web applications require a login system. Often, users of a website have different privileges, and to determine which resources they can access, they must first be identified through authentication.

This is typically achieved by setting up a session, which is a temporary information exchange between a user and a device. Sessions enable the server to store user-specific information, which can be used to manage access and maintain the user’s state across multiple requests.

In this recipe, we’ll implement an authentication layer for a Fastify server. Please refer to Chapter 6 for more information on Fastify.

Getting ready

Let’s start by creating a Fastify server:

1. Create a project directory named fastify-auth to work in and initialize the project with npm. We’ll also create some files and subdirectories that we’ll use later in this recipe:

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