Routing is not working for web api with realtions - asp.net-core

Question

I am creating web api using asp.net core. The api end point is logically mapped to resource's relations based on guidelines here
So my API looks like
http://tax.mydomain.com/api/v1/clients/1/batches/12/start
Where Client is parent of Batch, 1 is clientid and 12 is batchid, and Start is POST action method.
Here is the corresponding controller
public class TaxController : Controller
{
[HttpPost]
[Route("clients/{clientid}/batches/{batchid}/start")]
public void Start([FromRoute]string clientId, [FromRoute]string batchId,
[FromBody]IEnumerable<string> urls)
{
// do something
}
}
since api/v1 is common to all controllers i configured that in startup's Configure method. Also i want Home as default controller.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseMvc(routes =>
{
routes.MapRoute("default","api/v1/{controller=Home}/{action=Index}/{id?}");
});
}
However client is getting not found error for api http://tax.mydomain.com/api/v1/clients/1/batches/12/start

Answer 1

Any controller methods that do not have a route attribute use convention-based routing.
When you use [Route] attribute, you define attribute routing and so conventional routing is not used for that action/controller. Therefore, your controller is accessible by
http://tax.mydomain.com/clients/1/batches/12/start
As an option, you can use the fact, that attribute routes can be combined with inheritance. Set a Route attribute on the entire controller and this will work as route prefix (the same behavior as [RoutePrefix] attribute in WebApi):
[Route("api/v1")]
public class TaxController : Controller
{
}
More general example from routing documentation:
[Route("api/[controller]")]
public abstract class MyBaseController : Controller { ... }
public class ProductsController : MyBaseController
{
[HttpGet] // Matches '/api/Products'
public IActionResult List() { ... }
[HttpPost("{id}")] // Matches '/api/Products/{id}'
public IActionResult Edit(int id) { ... }
}

Answer 2

There are two things wrong with your setup
You call http://tax.mydomain.com/clients/1/batches/12/start but you don't have specified the controller name within it. This route looks for a controller named ClientsController. So the correct url would have to be http://tax.mydomain.com/tax/clients/1/batches/12/start instead
You seem to be using default MVC/Viewbased route, but your url suggest you use WebAPI.
When you use WebAPI to create a Rest service, you don't have any actions. Instead, actions map to the Http Verbs (GET (Read), PUT (update/replace), POST (insert), DELETE).
So for REST Services your default route should look like this instead: api/v1/{controller=Home}/{id?}