OData v4 unbound function with custom routing

Question

I have created a "Utilities" controller that is not bound to any model and contains only unbound functions.
I would like to be able to call this through a url like the following:
odata/Utilities/SomeMethod()

Right now I have to call it like the following:
odata/SomeMethod()

How do I create a custom route for "utilities"?

I have tried:

[ODataRoutePrefix("Utilities")]
public class UtilitiesController : ODataController

I have also tried:

[ODataRoute("Utilities/SomeMethod()"]
public string SomeMethod()

But both of these throw an error:
"The path template 'Utilities/SomeMethod()' on the action 'SomeMethod' in controller 'Utilities' is not a valid OData path template. Resource not found for the segment 'Utilities'."

Answer 1

You can override the default controller selector to achieve this. You can create a new class that inherits from DefaultHttpControllerSelector like this:

public class CustomControllerSelector : DefaultHttpControllerSelector
{

    public override string GetControllerName(HttpRequestMessage request)
    {
        string controllerName = null;
        // I haven't tested this, but here you can decide whether you want to 
        //  route to your new controller or not
        if (request.ODataProperties().Path.PathTemplate == "~/UnboundFunction")
        {
            controllerName = "UtilitiesController";
        }
        else
        {
            controllerName = base.GetControllerName(request);
        }

        return controllerName;
    }
}

And then you can replace the controller selector like this:

config.Services.Replace(typeof(IHttpControllerSelector), new CustomControllerSelector());

This lets you choose which controller to use at runtime for every request

Answer 2

1. Define the controller class:

   public class UtilitiesController : ODataController
   {
       [System.Web.Http.HttpGet]
       [ODataRoute("SomeMethod")]
       public string SomeMethod()
       {
           // add your code
       }
   }
   

2. Map the route:

   var config = new HttpConfiguration();
   
   var modelBuilder = new ODataConventionModelBuilder();
   
   modelBuilder.Function("SomeMethod").Returns<string>();
   
   config.MapODataServiceRoute("ODataRoute", "odata/Utilities", modelBuilder.GetEdmModel());