Eu sei que isso é bem depois que a pergunta foi respondida, mas estou usando uma abordagem diferente, pois estou usando injeção de dependência para instanciar meus controladores.
Substituí o IActionInvoker (injetando a propriedade ControllerActionInvoker do controlador) por uma versão que substitui o método InvokeActionMethod.
Isso significa que não há alteração na herança do controlador e pode ser facilmente removido quando eu atualizar para MVC4, alterando o registro do contêiner DI para TODOS os controladores
public class JsonNetActionInvoker : ControllerActionInvoker
{
protected override ActionResult InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary<string, object> parameters)
{
ActionResult invokeActionMethod = base.InvokeActionMethod(controllerContext, actionDescriptor, parameters);
if ( invokeActionMethod.GetType() == typeof(JsonResult) )
{
return new JsonNetResult(invokeActionMethod as JsonResult);
}
return invokeActionMethod;
}
private class JsonNetResult : JsonResult
{
public JsonNetResult()
{
this.ContentType = "application/json";
}
public JsonNetResult( JsonResult existing )
{
this.ContentEncoding = existing.ContentEncoding;
this.ContentType = !string.IsNullOrWhiteSpace(existing.ContentType) ? existing.ContentType : "application/json";
this.Data = existing.Data;
this.JsonRequestBehavior = existing.JsonRequestBehavior;
}
public override void ExecuteResult(ControllerContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
if ((this.JsonRequestBehavior == JsonRequestBehavior.DenyGet) && string.Equals(context.HttpContext.Request.HttpMethod, "GET", StringComparison.OrdinalIgnoreCase))
{
base.ExecuteResult(context); // Delegate back to allow the default exception to be thrown
}
HttpResponseBase response = context.HttpContext.Response;
response.ContentType = this.ContentType;
if (this.ContentEncoding != null)
{
response.ContentEncoding = this.ContentEncoding;
}
if (this.Data != null)
{
// Replace with your favourite serializer.
new Newtonsoft.Json.JsonSerializer().Serialize( response.Output, this.Data );
}
}
}
}
--- EDITAR - Atualizado para mostrar o registro do contêiner para controladores. Estou usando o Unity aqui.
private void RegisterAllControllers(List<Type> exportedTypes)
{
this.rootContainer.RegisterType<IActionInvoker, JsonNetActionInvoker>();
Func<Type, bool> isIController = typeof(IController).IsAssignableFrom;
Func<Type, bool> isIHttpController = typeof(IHttpController).IsAssignableFrom;
foreach (Type controllerType in exportedTypes.Where(isIController))
{
this.rootContainer.RegisterType(
typeof(IController),
controllerType,
controllerType.Name.Replace("Controller", string.Empty),
new InjectionProperty("ActionInvoker")
);
}
foreach (Type controllerType in exportedTypes.Where(isIHttpController))
{
this.rootContainer.RegisterType(typeof(IHttpController), controllerType, controllerType.Name);
}
}
public class UnityControllerFactory : System.Web.Mvc.IControllerFactory, System.Web.Http.Dispatcher.IHttpControllerActivator
{
readonly IUnityContainer container;
public UnityControllerFactory(IUnityContainer container)
{
this.container = container;
}
IController System.Web.Mvc.IControllerFactory.CreateController(System.Web.Routing.RequestContext requestContext, string controllerName)
{
return this.container.Resolve<IController>(controllerName);
}
SessionStateBehavior System.Web.Mvc.IControllerFactory.GetControllerSessionBehavior(RequestContext requestContext, string controllerName)
{
return SessionStateBehavior.Required;
}
void System.Web.Mvc.IControllerFactory.ReleaseController(IController controller)
{
}
IHttpController IHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
{
return this.container.Resolve<IHttpController>(controllerType.Name);
}
}