If I make a custom attribute that I can decorate my dotnet core api controller methods with, how can I get the http payload (headers/body) sent to that method inside the custom attribute? The [Authorize] attribute does it so I know it's possible. Once I do this and check stuff in the payload, how do I then either continue with the method that was decorated or instead return an http status code and message?

I'm trying to do authorization with just an apikey instead of the whole password/jwt flow.