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

Using the newer ASP.NET Web API, in Chrome I am seeing XML - how can I change it to request JSON so I can view it in the browser? I do believe it is just part of the request headers, am I correct in that?

Solution 1:

Note: Read the comments of this answer, it can produce a XSS Vulnerability if you are using the default error handing of WebAPI

I just add the following in App_Start / WebApiConfig.cs class in my MVC Web API project.

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

That makes sure you get JSON on most queries, but you can get XML when you send text/xml.

If you need to have the response Content-Type as application/json please check Todd's answer below.

NameSpace is using System.Net.Http.Headers.

Solution 2:

If you do this in the WebApiConfig you will get JSON by default, but it will still allow you to return XML if you pass text/xml as the request Accept header.

Note: This removes the support for application/xml

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

        var appXmlType = config.Formatters.XmlFormatter.SupportedMediaTypes.FirstOrDefault(t => t.MediaType == "application/xml");
        config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType);
    }
}

If you are not using the MVC project type and therefore did not have this class to begin with, see this answer for details on how to incorporate it.

Solution 3:

Using RequestHeaderMapping works even better, because it also sets the Content-Type = application/json in the response header, which allows Firefox (with JSONView add-on) to format the response as JSON.

GlobalConfiguration.Configuration.Formatters.JsonFormatter.MediaTypeMappings
.Add(new System.Net.Http.Formatting.RequestHeaderMapping("Accept", 
                              "text/html",
                              StringComparison.InvariantCultureIgnoreCase,
                              true, 
                              "application/json"));

Solution 4:

I like Felipe Leusin's approach best - make sure browsers get JSON without compromising content negotiation from clients that actually want XML. The only missing piece for me was that the response headers still contained content-type: text/html. Why was that a problem? Because I use the JSON Formatter Chrome extension, which inspects content-type, and I don't get the pretty formatting I'm used to. I fixed that with a simple custom formatter that accepts text/html requests and returns application/json responses:

public class BrowserJsonFormatter : JsonMediaTypeFormatter
{
    public BrowserJsonFormatter() {
        this.SupportedMediaTypes.Add(new MediaTypeHeaderValue("text/html"));
        this.SerializerSettings.Formatting = Formatting.Indented;
    }

    public override void SetDefaultContentHeaders(Type type, HttpContentHeaders headers, MediaTypeHeaderValue mediaType) {
        base.SetDefaultContentHeaders(type, headers, mediaType);
        headers.ContentType = new MediaTypeHeaderValue("application/json");
    }
}

Register like so:

config.Formatters.Add(new BrowserJsonFormatter());

Solution 5:

MVC4 Quick Tip #3–Removing the XML Formatter from ASP.Net Web API

In Global.asax add the line:

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

like so:

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

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

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