Chakram has a lot of examples of using JSON requests, however I needed a working solution for chakram multipart file upload and authenticate using Authorization header.
A quick example to illustrate an implementation of a custom Unauthorized response body in ASP.NET Core 2.0. The implementation is based on the AuthorizeFilter from Microsoft MVC framework.
This blog post shows a quick example of implementing custom authentication in .NET Core 2.0 to secure your Web API. And in most cases you do want to secure your Web APIs, even though they were internal (micro)services only. If you don’t have a proper Identity provider e. g. Identity Server in place, and just need a quick solution, then a simple option is to validate Authorization header against a hardcoded value.