Implementing a custom Route Attribute for Web API that considers Content-Type. This allows for routing based on the data encoding being supplied by the HTTP Request, not just the path and parameters it was sent to.
One of the things HttpClient does for you is to construct the Request Message automatically when you execute GetAsync. To add or change an HTTP header (such as “User-Agent”) however, you will need to construct the Request Message yourself. Luckily this is rather simple to carry out.
I’m working with a REST API that requires Basic HTTP Authentication. This is pretty commonplace and something I’ve done it many times in the past in web and Silverlight applications. WinRT was very similar but (as with everything in WinRT) has its own nuances.