ASP.NET Web API 2 allows to set route name on a controller:

Route names are useful for generating links, so that you can include a link in an HTTP response.

I define two controllers, each of them returns a link to another one in the response (it does not matter if that is a SSC ServicesApiController or standard Web API ApiController):

[Route("api/valuesA", Name = "ValuesA")]
public class ValuesAController : ServicesApiController
    public object Get()
        var link = Url.Link("ValuesB", new { });
        return new { link_to_valuesB = link };

[Route("api/valuesB", Name = "ValuesB")]
public class ValuesBController : ServicesApiController
    public object Get()
        var link = Url.Link("ValuesA", new { });
        return new { link_to_valuesA = link };

Request api/valuesA returns link to valuesB:

    "link_to_valuesB": "http://mysite/api/valuesB"

The controllers work fine, but all the existing SSC controllers inherited from either EntityService<> or ServiceBaseODataController<> class just crash. All the SPEAK-based marketing applications heavily rely on the EntityService<> and all of them just stop working returning numerous 500 Server Errors:

{"Message":"An error has occurred.","ExceptionMessage":"A route named 'ValuesA' is already in the route collection. Route names must be unique.\r\n
Parameter name: name","ExceptionType":"System.ArgumentException","StackTrace":"   at System.Web.Routing.RouteCollection.Add(String name, RouteBase item)\r\n
at System.Web.Http.Routing.AttributeRoutingMapper.AddGenerationHooksForSubRoutes(HttpRouteCollection routeTable, IEnumerable`1 entries)\r\n
at System.Web.Http.Routing.AttributeRoutingMapper.<>c__DisplayClass2.<MapAttributeRoutes>b__0(HttpConfiguration config)\r\n
at System.Web.Http.HttpConfiguration.ApplyControllerSettings(HttpControllerSettings settings, HttpConfiguration configuration)\r\n
at System.Web.Http.Controllers.HttpControllerDescriptor.InvokeAttributesOnControllerType(HttpControllerDescriptor controllerDescriptor, Type type)\r\n
at System.Web.Http.Controllers.HttpControllerDescriptor..ctor(HttpConfiguration configuration, String controllerName, Type controllerType)\r\n
at System.Web.Http.Dispatcher.DefaultHttpControllerSelector.InitializeControllerInfoCache()\r\n
at System.Lazy`1.CreateValue()\r\n
--- End of stack trace from previous location where exception was thrown ---\r\n
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n
at System.Lazy`1.get_Value()\r\n
at System.Web.Http.Dispatcher.DefaultHttpControllerSelector.SelectController(HttpRequestMessage request)\r\n
at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()"}

Any idea why is that? (Sitecore 8.2.3).

  • This may be related to the order that routes are registered. How are you registering your custom routes? Jun 21, 2017 at 16:43
  • Via attributes, as in the question above Jun 21, 2017 at 16:45
  • See @Richard Seal's answer below. You are using named Routes. Those must be registered somewhere. Jun 21, 2017 at 17:29
  • I suppose there is no need to register the routes since that's already done by SSC. The problem (as I see it) is opposite. The route is being registered twice: "ExceptionMessage":"A route named 'ValuesA' is already in the route collection.. Jun 22, 2017 at 7:22

2 Answers 2


This will be the way the routes get registered when applied by attributes. The correct way to register your own routes with Sitecore is to write a custom initialize pipeline processor and patch it in before the Sitecore InitializeRoutes processor.

Take this example from the Habitat project:

public class RegisterWebApiRoutes
    public void Process(PipelineArgs args)
        RouteTable.Routes.MapRoute("Feature.Accounts.Api", "api/accounts/{action}", new
            controller = "Accounts"

This registers the route, and then the config registers the pipeline processor:

<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
                <processor type="Sitecore.Feature.Accounts.Pipelines.RegisterWebApiRoutes, Sitecore.Feature.Accounts" 
                           patch:before="processor[@type='Sitecore.Mvc.Pipelines.Loader.InitializeRoutes, Sitecore.Mvc']" />

Notice that you register before the Sitecore processor to initialize routes, this is important so you don't override any of the standard Sitecore routes.

  • thanks for your answer but are you sure I need to register the routes? The error says it's already registered. BTW, the pipeline processor you shared deals with MVC controllers but I'm designing controllers using Web API 2 (the route registration mechanism is different). Jun 22, 2017 at 7:28

This is rather a workaround than the answer to the original question.

I used Richard Seal's idea and registered my Web API controllers manually. I removed all the [Route(Name="...")] attributes, implemented Sitecore.Services.Infrastructure.Web.Http.IMapRoutes interface and registered it instead of the default one:

public class MyRouteMapper : IMapRoutes
    private readonly IMapRoutes _defaultRoutes = new DefaultRouteMapper();

    public void MapRoutes(HttpConfiguration config)
        config.Routes.MapHttpRoute("ValuesA", "api/valuesA", new { });
        config.Routes.MapHttpRoute("ValuesB", "api/valuesB", new { });

    public void MapRoutes(RouteCollection routes)

  <setting name="Sitecore.Services.RouteMapper">
    <patch:attribute name="value">MyProj.MyRouteMapper,MyProj</patch:attribute>

Now all the existing and new controllers work fine but the question with named routes is still open.

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