This project was inspired by the WebApi.Hal (https://github.com/JakeGinnivan/WebApi.Hal) opensource project.

Given an ASP.NET Web Api 2.x project...

1. I want to be able to return just a plain old DTO from my controller action.
2. I want to have some default metadata configured that is associated with my DTO.
3. I want to be able to add/modify the metadata associated with my DTO contextually in my controller action.
4. I want to be able to plug-in different Formatters to support different Hypermedia formats over time.
5. I only want to return hypermedia format (with metadata) if the Accept header matches a registered formatter. Otherwise, I want the plain old DTO returned.

A custom ActionFilterAttribute (HypermediaFilter) can solve # 1 by intercepting the Request and replacing it with a HypermediaObject.

A configuration registration mechanism similar to the appenders in WebApi.Hal can solve # 2.

Storing extra Links metadata in the Request.Properties (made easier with extension methods) can solve # 3. Then, the custom ActionFilterAttribute can merge the default metadata with the contextual metadata from the Request when it encapsulates the DTO in the HypermediaObject.

By keeping the metadata fairly generic and not tying it directly to HAL or any other specific Hypermedia format standard, we can support # 4.

By checking the Accept header inside the custom ActionFilterAttribute, we can support # 5.