Authentication

In the last chapter, we created a live web-based API using an Azure Function App and updated our app to use it instead of static, hardcoded data. When we created the API, we made it available anonymously, which means anyone can access the data within it. Most web-based APIs require some level of authentication. In some cases, it may be an API key you are provided by the API owner. In other cases, you may be required to sign in with credentials, in order to obtain an authorization token. Whether you are provided a key or granted a token through an authorization process, that key or token can then be used to authenticate all access to the API. In this chapter, we are going to update our API to require authorization, and update our app to allow users to sign in to access the API.

In this chapter, we'll cover the following topics:

• Adding authentication to the Azure Function App
• Using the Xamarin.Auth library to easily perform OAuth and securely communicate...