ASP.net Web Api Versioning

Question

I have ASP.net Web Api project and I decided that it was time to support versioning. I am using official Microsoft Nuget to support versioning (more info here), and I decided to version by namespace (as exampled here).

Unfortunately I cannot get code to work. If I call my method like this:

http://localhost:7291/api/Saved/GetNumberOfSavedWorkoutsForUser?api-version=2.0

I get error:

Multiple types were found that match the controller named 'Saved'. This can happen if the route that services this request ('api/{controller}/{action}/{id}') found multiple controllers defined with the same name but differing namespaces, which is not supported.

And if I call it like this: http://localhost:7291/v2/Saved/GetNumberOfSavedWorkoutsForUser

I get error 404:

The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

I am not sure what I am doing wrong. Here is my code:

Startup.cs

public void Configuration(IAppBuilder app)
    {
        var configuration = new HttpConfiguration();
        var httpServer = new HttpServer(configuration);


        app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);

        // reporting api versions will return the headers "api-supported-versions" and "api-deprecated-versions"
        configuration.AddApiVersioning(o => 
        {
            o.AssumeDefaultVersionWhenUnspecified = true;
            o.ReportApiVersions = true; 
            o.DefaultApiVersion = ApiVersion.Default;
        });


        configuration.Routes.MapHttpRoute(
            "VersionedUrl",
            "v{apiVersion}/{controller}/{action}/{id}",
            defaults: null,
            constraints: new { apiVersion = new ApiVersionRouteConstraint() });

        configuration.Routes.MapHttpRoute(
            "VersionedQueryString",
            "api/{controller}/{action}/{id}",
            defaults: null);


        app.UseWebApi(httpServer);

        ConfigureAuth(app);
    }

Saved Controller (v1)

namespace Master.Infrastructure.Api.Controllers
{

    [Authorize]
    [RoutePrefix("api/Saved")]
    [ApiVersion("1.0")]
    public class SavedController : ApiController
    {

        private readonly IUserService _userService;

        public SavedController(IUserService userService)
        {
            _userService = userService;

        }


        [HttpGet]
        [ActionName("GetNumberOfSavedWorkouts")]
        public async Task<NumberOfSavedWorkouts> GetNumberOfSavedWorkouts()
        {
            var numOfSavedWorkouts = new NumberOfSavedWorkouts
            {
                CurrentNumberOfSavedWorkouts =
                    await _userService.GetNumberOfSavedWorkoutsForUserAsync(User.Identity.GetUserId())
            };

            return numOfSavedWorkouts;
        }

    }
}

Saved Controller (v2)

namespace Master.Infrastructure.Api.V2.Controllers
{
    [Authorize]
    [ApiVersion("2.0")]
    [RoutePrefix("v{version:apiVersion}/Saved")]
    public class SavedController : ApiController
    {

        private readonly ISavedWorkoutService _savedWorkoutService;


        public SavedController(ISavedWorkoutService savedWorkoutService)
        {       
            _savedWorkoutService = savedWorkoutService;
        }


        [ActionName("GetNumberOfSavedWorkoutsForUser")]
        public async Task<IHttpActionResult> GetNumberOfSavedWorkoutsForUser()
        {
            var cnt = await _savedWorkoutService.CountNumberOfSavedWorkoutsForUser(User.Identity.GetUserId());

            return Ok(cnt);
        }
    }
}

Answer 1

Your routes are incorrect. I strongly discourage you from mixing routing styles unless you really need to. It can be very difficult to troubleshoot.

There are several things going on here:

1. You have configurations to version both by query string and URL segment, which one do you want? I would choose only one. The default and my recommendation would be to use the query string method.
2. Your convention-based route is different from the attribute-base route
3. Since you have RoutePrefixAttribute defined, it appears you prefer the attribute-routing style. I would remove all convention-based routes (ex: configuration.Routes.MapHttpRoute).

In your convention, the route template:

v{apiVersion}/{controller}/{action}/{id}

but in your attribute it's:

api/Saved

Neither of these will match your expected routes:

http://localhost:7291/api/Saved/GetNumberOfSavedWorkoutsForUser http://localhost:7291/v2/Saved/GetNumberOfSavedWorkoutsForUser

For the query string method using route attributes, things should look like:

configuration.AddApiVersioning(o => o.ReportApiVersions = true);

namespace Master.Infrastructure.Api.Controllers
{
    [Authorize]
    [ApiVersion("1.0")]
    [RoutePrefix("api/Saved")]
    public class SavedController : ApiController
    {
       private readonly IUserService _userService;
       public SavedController(IUserService userService) => _userService = userService;

       [HttpGet]
       [Route("GetNumberOfSavedWorkouts")]
       public async Task<IHttpActionResult> GetNumberOfSavedWorkouts()
       {
            var userId = User.Identity.GetUserId();
            var count = await _userService.GetNumberOfSavedWorkoutsForUserAsync(userId);
            return Ok(new NumberOfSavedWorkouts(){ CurrentNumberOfSavedWorkouts = count });
       }
    }
}

namespace Master.Infrastructure.Api.V2.Controllers
{
    [Authorize]
    [ApiVersion("2.0")]
    [RoutePrefix("api/Saved")]
    public class SavedController : ApiController
    {
       private readonly ISavedWorkoutService _savedWorkoutService;
       public SavedController(ISavedWorkoutService savedWorkoutService) => _savedWorkoutService = savedWorkoutService;

       [HttpGet]
       [Route("GetNumberOfSavedWorkoutsForUser")]
       public async Task<IHttpActionResult> GetNumberOfSavedWorkoutsForUser()
       {
            var userId = User.Identity.GetUserId();
            var count = await _savedWorkoutService.CountNumberOfSavedWorkoutsForUser(userId);
            return Ok(count);
       }
    }
}

The following should then work:

http://localhost:7291/api/Saved/GetNumberOfSavedWorkouts?api-version=1.0 http://localhost:7291/api/Saved/GetNumberOfSavedWorkoutsForUser?api-version=2.0

I hope that help.s