Question

I’m ramping up on MVC 4’s Web API and I’m a bit confused about the default formatting. I want the API data to be in JSON. However, it’s returning it in XML. According to the MVC 4 getting started video at http://www.asp.net/web-api/videos/getting-started/your-first-web-api, it should be JSON by default. But when I create a new Web Api project and run the sample, I get this:

<ArrayOfstring><string>value1</string><string>value2</string></ArrayOfstring>

I’ve been running around in circles trying to get this in JSON but apparently there is a lot of misinformation about this. Such as:

1. If I add “application/json” to the content type header, it should return JSON. This doesn’t work, but I’m suspecting I don’t have the header variable name right as I’m not finding the exact name to use. I’ve tried “Content-Type” and “contentType” in the request headers with no luck. Besides, I want JSON by default, not according to header info.
2. If I create a JsonFormatter and add it in Application_Start GlobalConfiguration.Configuration.Formatters.Insert(0, new JsonNetFormatter(serializerSettings)); It should do the trick. But I gathered this depreciated as none of the examples are working.

What could I do, something simple preferably, to output data in JSON format by default?

Answer 1

Add this to GLOBAL.ASAX to get the response to be application/json

GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();

So it should look like this in context:

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();

    RegisterGlobalFilters(GlobalFilters.Filters);
    RegisterRoutes(RouteTable.Routes);

    BundleTable.Bundles.RegisterTemplateBundles();
    GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();
}

OR if you need to preserve XML as a media type you could instead edit App_Start/WebApiConfig.cs:

config.Formatters.JsonFormatter.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html") );

Which makes JSON the default response for a web browser but returns text/html.

Source