Implementing browser-based authentication

In the Logging in with Facebook recipe in Chapter 8, Working with Application Logic and Data, we will cover using the Expo Facebook component to create a login workflow for providing our app with the user's basic Facebook account information. Expo also provides a Google component, which provides similar functionality for getting a user's Google account information. But what do we do if we want to create a login workflow that uses account information from a different site? In this case, Expo provides the AuthSession component.

AuthSession is built on Expo's WebBrowser component, which we've already used in Chapter 4, Implementing Complex User Interfaces – Part II. The typical login workflow consists of four steps:

1. The user initiates the login process
2. The web browser opens to the login page
3. The authentication...