Route attribute routing with query strings when there are multiple routes

Question

I have this:

[HttpGet]
[Route("Cats")]
public IHttpActionResult GetByCatId(int catId)

[HttpGet]
[Route("Cats")]
public IHttpActionResult GetByName(string name)

They are called by providing the query string eg Cats?catId=5

However MVC Web API will say you can't have multiple routes that are the same (both routes are "Cats".

How can I get this to work so MVC Web API will recognize them as separate routes? Is there something I can put into the Route property? It says that ? is an invalid character to put into a route.

Answer 1

You can merge the two actions in question into one

[HttpGet]
[Route("Cats")]
public IHttpActionResult GetCats(int? catId = null, string name = null) {

    if(catId.HasValue) return GetByCatId(catId.Value);

    if(!string.IsNullOrEmpty(name)) return GetByName(name);

    return GetAllCats();
}

private IHttpActionResult GetAllCats() { ... }

private IHttpActionResult GetByCatId(int catId) { ... }    

private IHttpActionResult GetByName(string name) { ... }

Or for more flexibility try route constraints

Referencing Attribute Routing in ASP.NET Web API 2 : Route Constraints

Route Constraints

Route constraints let you restrict how the parameters in the route template are matched. The general syntax is "{parameter:constraint}". For example:

[Route("users/{id:int}"]
public User GetUserById(int id) { ... }

[Route("users/{name}"]
public User GetUserByName(string name) { ... }

Here, the first route will only be selected if the "id" segment of the URI is an integer. Otherwise, the second route will be chosen.