How do I get ASP.NET Web API to return JSON instead of XML using Chrome?

Answer 1

Here is a solution similar to jayson.centeno's and other answers, but using the built-in extension from System.Net.Http.Formatting.

public static void Register(HttpConfiguration config)
{
    // add support for the 'format' query param
    // cref: http://blogs.msdn.com/b/hongyes/archive/2012/09/02/support-format-in-asp-net-web-api.aspx
    config.Formatters.JsonFormatter.AddQueryStringMapping("$format", "json", "application/json");
    config.Formatters.XmlFormatter.AddQueryStringMapping("$format", "xml", "application/xml");

    // ... additional configuration
 }

The solution was primarily geared toward supporting $format for OData in the early releases of WebApi, but it also applies to the non-OData implementation, and returns the Content-Type: application/json; charset=utf-8 header in the response.

It allows you to tack &$format=json or &$format=xml to the end of your uri when testing with a browser. It does not interfere with other expected behavior when using a non-browser client where you can set your own headers.