asp.net webapi 2 attribute routing not working

Question

I have visual studio 2012 installed with mvc4 using .net framework 4.5. Now I want to use webapi2 with attribute writing and i want my hlep page show all the endpoints properly.

In my solution i added a new mvc4 base emtpy project and using nuget i upgraded to mvc5 and then i have installed webapi2 packages. lastly i have installed help package for webapi2.

now when i use routeprefix I cant see any content on help page and when i try to access my webapi endpoint in browsers it throws following error.

http://expressiis.com/api/v1/

   <Error>
    <Message>
    No HTTP resource was found that matches the request URI 'http://expressiis.com/api/v1/'.
    </Message>
    <MessageDetail>
    No type was found that matches the controller named 'v1'.
    </MessageDetail>
    </Error>

namespace WebApi.Controllers
{
    [RoutePrefix("api/v1")]
    public class SubscribersController : ApiController
    {
        // GET api/<controller>   
        [Route("")]
        [HttpGet]
        public IQueryable<string> Get()
        {
            return new string[] { "value1", "value2" }.AsQueryable();
        }


    }
}

Answer 1

Based on your information, it looks like you are not calling the httpConfig.MapHttpAttributeRoutes() (Make sure to call this before any traditional routing registrations)

Since you haven't called MapHttpAttributeRoutes, your request seems to be matching a traditional route, for example, like api/{controller}. This will not work because routes matching traditional routes will never see controllers/actions decorated with attribute routes.