Asp.net-mvc – All ASP.NET Web API controllers return 404

asp.net-mvcasp.net-mvc-4asp.net-web-api

I'm trying to get an API Controller to work inside an ASP.NET MVC 4 web app. However, every request results in a 404 and I'm stumped. :/

I have the standard API controller route from the project template defined like:

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

The registration is invoked in Global.asax:

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

    // Register API routes
    WebApiConfig.Register(GlobalConfiguration.Configuration);

    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);

    RouteConfig.RegisterRoutes(RouteTable.Routes);
}

I have a basic API controller like this:

namespace Website.Controllers
{
    public class FavoritesController : ApiController
    {       
        // GET api/<controller>
        public IEnumerable<string> Get()
        {
            return new [] { "first", "second" };
        }

        // PUT api/<controller>/5
        public void Put(int id)
        {

        }

        // DELETE api/<controller>/5
        public void Delete(int id)
        {

        }
    }
}

Now, when I browse to localhost:59900/api/Favorites I expect the Get method to be invoked, but instead I get a 404 status code and the following response:

<Error>
   <Message>
       No HTTP resource was found that matches the request URI 'http://localhost:59900/api/Favorites'.
   </Message>
   <MessageDetail>
      No type was found that matches the controller named 'Favorites'.
   </MessageDetail>
</Error>

Any help would be greatly appreciated, I'm losing my mind a little bit over here. 🙂 Thanks!

Best Answer

One thing I ran into was having my configurations registered in the wrong order in my GLobal.asax file for instance:

Right Order:

AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);

Wrong Order:

AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
WebApiConfig.Register(GlobalConfiguration.Configuration);

Just saying, this was my problem and changing the order is obvious, but sometimes overlooked and can cause much frustration.

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.

C# – Best practice to return errors in ASP.NET Web API

For me I usually send back an HttpResponseException and set the status code accordingly depending on the exception thrown and if the exception is fatal or not will determine whether I send back the HttpResponseException immediately.

At the end of the day it's an API sending back responses and not views, so I think it's fine to send back a message with the exception and status code to the consumer. I currently haven't needed to accumulate errors and send them back as most exceptions are usually due to incorrect parameters or calls etc.

An example in my app is that sometimes the client will ask for data, but there isn't any data available so I throw a custom NoDataAvailableException and let it bubble to the Web API app, where then in my custom filter which captures it sending back a relevant message along with the correct status code.

I am not 100% sure on what's the best practice for this, but this is working for me currently so that's what I'm doing.

Update:

Since I answered this question a few blog posts have been written on the topic:

https://weblogs.asp.net/fredriknormen/asp-net-web-api-exception-handling

(this one has some new features in the nightly builds) https://docs.microsoft.com/archive/blogs/youssefm/error-handling-in-asp-net-webapi

Update 2

Update to our error handling process, we have two cases:

For general errors like not found, or invalid parameters being passed to an action we return a HttpResponseException to stop processing immediately. Additionally for model errors in our actions we will hand the model state dictionary to the Request.CreateErrorResponse extension and wrap it in a HttpResponseException. Adding the model state dictionary results in a list of the model errors sent in the response body.
For errors that occur in higher layers, server errors, we let the exception bubble to the Web API app, here we have a global exception filter which looks at the exception, logs it with ELMAH and tries to make sense of it setting the correct HTTP status code and a relevant friendly error message as the body again in a HttpResponseException. For exceptions that we aren't expecting the client will receive the default 500 internal server error, but a generic message due to security reasons.

Update 3

Recently, after picking up Web API 2, for sending back general errors we now use the IHttpActionResult interface, specifically the built in classes for in the System.Web.Http.Results namespace such as NotFound, BadRequest when they fit, if they don't we extend them, for example a NotFound result with a response message:

public class NotFoundWithMessageResult : IHttpActionResult
{
    private string message;

    public NotFoundWithMessageResult(string message)
    {
        this.message = message;
    }

    public Task<HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken)
    {
        var response = new HttpResponseMessage(HttpStatusCode.NotFound);
        response.Content = new StringContent(message);
        return Task.FromResult(response);
    }
}

Best Answer

Related Solutions

Json – How to get ASP.NET Web API to return JSON instead of XML using Chrome

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

C# – Best practice to return errors in ASP.NET Web API

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