Using the same control to return JSON/XML/HTML with Web API MVC4

Question

I am guessing it has been asked before but I did not see it and thought maybe I am missing something fundamental. My question is why can't I have one API controller that bases the format of result on the accepted content format(ie application/json)? Maybe I am being lazy - but I rather do something like if html is the expected result format than let me return a view, if json is the accept format than I can return JSOn -etc... If I have two namespaces, then that is also two methods I have to maintain - when the only difference is the media format.

Answer 1

When you return an object from an action in a web api controller, what is actually going on behind the scenes looks like this:

 public class SessionController : ApiController
    {

        public HttpResponseMessage Get(int id)
        {
            var vm = new SessionDetailViewModel {Speaker = "Bob", Title = "Bob's talk"};

            var conneg = new DefaultContentNegotiator();
            var result = conneg.Negotiate(typeof (SessionDetailViewModel), this.Request,Configuration.Formatters);
            var content = new ObjectContent<SessionDetailViewModel>(vm, result.Formatter,result.MediaType);

            return new HttpResponseMessage() {Content = content};
        }
    }

As long as you have the appropriate set of formatters that can map the returned object to the wire format then conneg will happen automatically.