Using Multiple Auth Handlers In ASP.NET Core
ASP.NET Core makes it extremely easy to configure authentication right out of the box with a choice from a plethora of different built-in authentication handlers. Everything from Single Sign On with Facebook to JWT to simple cookie authentication is available right out of the box. Where I found the ASP.NET Core documentation lacking was when attempting to use multiple authentication handlers at the same time. I was already using the JWT handler in my application, but I wanted to have my custom API key authentication handler run and handle authentication if no Authorization header was supplied as part of the request. Finding the answer to how to accomplish that took longer than it should have, so hopefully this blog post will save others from that same fate.