Why is my attribute routing not working? - asp.net-mvc

Question

This is what my controller looks like:
[Route("api/[controller]")]
[Produces("application/json")]
public class ClientsController : Controller
{
private readonly IDataService _clients;
public ClientsController(IDataService dataService)
{
_clients = dataService;
}
[HttpPost]
public int Post([Bind("GivenName,FamilyName,GenderId,DateOfBirth,Id")] Client model)
{
// NB Implement.
return 0;
}
[HttpGet("api/Client/Get")]
[Produces(typeof(IEnumerable<Client>))]
public async Task<IActionResult> Get()
{
var clients = await _clients.ReadAsync();
return Ok(clients);
}
[HttpGet("api/Client/Get/{id:int}")]
[Produces(typeof(Client))]
public async Task<IActionResult> Get(int id)
{
var client = await _clients.ReadAsync(id);
if (client == null)
{
return NotFound();
}
return Ok(client);
}
[HttpGet("api/Client/Put")]
public void Put(int id, [FromBody]string value)
{
}
[HttpGet("api/Client/Delete/{id:int}")]
public void Delete(int id)
{
}
}
Yet when I request the URL /api/Clients/Get, as follows:
json = await Client.GetStringAsync("api/Clients/Get");
I get back the following exception:
AmbiguousActionException: Multiple actions matched. The following
actions matched route data and had all constraints satisfied:
Assessment.Web.Controllers.ClientsController.Index (Assessment.Web)
Assessment.Web.Controllers.ClientsController.Details (Assessment.Web)
Assessment.Web.Controllers.ClientsController.Create (Assessment.Web)
Client is an HttpClient. Please note that no GET action matched the route data, despite the same name, id.
What could be wrong here?

Answer 1

You are using the attributes wrong.
You have a route on the controller
[Route("api/[controller]")]
which would map to api/Clients and prefix that to any action routes in the controller.
So that means that
[HttpGet("api/Client/Get")] // Matches GET api/Clients/api/Client/Get
[Produces(typeof(IEnumerable<Client>))]
public async Task<IActionResult> Get()
{
var clients = await _clients.ReadAsync();
return Ok(clients);
}
Matches a GET to api/Clients/api/Client/Get because of the route prefix on the controller.
Referencing Routing to Controller Actions
You need to update the attribute routes on the actions accordingly
[Route("api/[controller]")]
[Produces("application/json")]
public class ClientsController : Controller {
private readonly IDataService _clients;
public ClientsController(IDataService dataService)
{
_clients = dataService;
}
[HttpPost] //Matches POST api/Clients
public int Post([Bind("GivenName,FamilyName,GenderId,DateOfBirth,Id")] Client model) {
// NB Implement.
return 0;
}
[HttpGet("Get")] //Matches GET api/Clients/Get
[Produces(typeof(IEnumerable<Client>))]
public async Task<IActionResult> Get() {
//...code removed for brevity
}
[HttpGet("Get/{id:int}")] //Matches GET api/Clients/Get/5
[Produces(typeof(Client))]
public async Task<IActionResult> Get(int id) {
//...code removed for brevity
}
[HttpGet("Put")] //Matches PUT api/Clients/Put
public void Put(int id, [FromBody]string value) {
//...code removed for brevity
}
[HttpGet("Delete/{id:int}")] //Matches GET api/Clients/Delete/5
public void Delete(int id) {
}
}
The delete action should actually be refactored to a HTTP DELETE and should return a IActionResult
[HttpDelete("Delete/{id:int}")] //Matches DELETE api/Clients/Delete/5
public IActionResult Delete(int id) {
//...code removed for brevity
}

Answer 2

I Think there is a typo in the route, it should be Clients with an (s) at the end instead of Client.
[HttpGet("api/Clients/Get")]
instead of
[HttpGet("api/Client/Get")]
Or change the call to the endpoint to :
json = await Client.GetStringAsync("api/Client/Get");