For more information about HTTP in .NET Core, or using ASP.NET Core, you have a wealth of resources at your disposal. Particularly, I'd recommend Hands-On Full-Stack Web Development with ASP.NET Core, by Tamir Dresher, Amir Zuker, and Shay Friedman, available through Packt Publishing here: https://www.packtpub.com/web-development/hands-full-stack-web-development-aspnet-core.
If you want to take a deeper dive into the patterns and principles that informed the developers of ASP.NET Core, I'd recommend reading ASP.NET Core 2 Fundamentals, by Onur Gumus and Mugilan T S Ragupathi. It's also available from Packt, and you can find it here: https://www.packtpub.com/web-development/aspnet-core-2-fundamentals.
If you're more interested in the fundamentals of the MVC design pattern, and how ASP.NET Core uses it to provide clean architectural templates...
