The approach that we chose to retrieve the appsettings.json configuration values makes use of the generic IConfiguration object, which can be queried using the preceding string-based syntax. This approach is rather practical; however, if we want to retrieve this data in a more robust way, for example, in a strongly-typed fashion, we can--and should--implement something better. Although we won't dive deeper into that within this book, we can suggest reading the following great articles showing three different approaches to achieve this result:

The first one, written by Rick Strahl, explains how to do that using the IOptions<T> provider interface:

https://weblog.west-wind.com/posts/2016/may/23/strongly-typed-configuration-settings-in-aspnet-core

The second, by Filip W, explains how to do that with a simple POCO class, thus avoiding the IOptions<T> interface and the extra dependencies required by the preceding approach:

https://www.strathweb.com/2016/09/strongly-typed-configuration-in-asp-net-core-without-ioptionst/

The third, by Khalid Abuhakmeh, shows an alternative way to use a standard POCO class and directly register it as a Singleton with the ServicesCollection, while also (optionally) shielding it from unwanted modifications due to development mistakes:

https://rimdev.io/strongly-typed-configuration-settings-in-asp-net-core-part-ii/

All of these approaches were meant to work with .NET Core 1.x; however, they can still be very usable in .NET Core 2. That said, if we were to choose, we would probably go with the latter, as we found it to be the most clean and clever one.