Sign in with Apple isn't hard, but it required some knowledge outside the Apple documentation to understand what they are trying to say.
Apple documentation introduced you with new terms and new things that you never heard of, stuff like JWT, JWK, weird public key format, creating a private key, and an ID for your web service. After finishing it, you might not even know where to start.
This book will prepare you with everything you need to know about Sign in with Apple. Then guide you step by step on what to do to implement it in your existing project.
Chapter 1 - Introducing
A brief introduction of what is Sign in with Apple and how it looks like. This will give you an idea of what Apple has to offer.
Chapter 2 - OAuth + OpenID Connect
Apple is good at explaining something without saying the underlying technology. Apple had a whole session of a new Combine framework without reference anything about React. In this chapter, we will learn about the underlying technology of Sign in with Apple.
Chapter 3 - Preparing
There are many parties involved in Sign in with Apple, backed, frontend, and mobile. As an iOS developer, you might not need to understand everything in this sign in flow, but you are likely the one who prepares everything your colleague would ask, e.g., public/private key, client_id, a new app id, etc. This chapter will make sure you got everything you need.
Chapter 4 - Authenticate with Firebase
This chapter will focus on the mobile side and leave the backend to the third-party. We will use everything from chapter 3 and put it into action.
Chapter 5 - Authenticate with your own backend
We will remove Firebase and make our own backend. Even you don't code for backend; it might help you in communicating with your colleagues.
Chapter 6 - Sign in with Apple for web application
I will show you how to integrate Sign in with Apple to a web application in this chapter.