How to pass multiple params to WebAPI?

Question

I have the following URL:

http://localhost/api/values/100/some+string+here

In the WebAPI app ValuesController, I have this:

[HttpGet]
[Route("api/values/{p1}/{p2}")]
public HttpResponseMessage Get (string p1, string p2) {
...
}

For the caller, it never hits the web api. Instead, it comes back with a 404.

Any idea what is wrong?

Answer 1

You are using Attribute Routing in ASP.NET Web API 2. Make sure you configure your web api to use Attribute routing with MapHttpAttributeRoutes.

public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // Attribute routing.
        config.MapHttpAttributeRoutes();

        // Convention-based routing.
        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );
    }
}

Next make sure you defined your controller properly

public class ValuesController : ApiController {
    //GET api/values/100/some-string-here
    [HttpGet]
    [Route("api/values/{p1}/{p2}")]
    public HttpResponseMessage Get (string p1, string p2) {
    ...
    }
}

You could even use RoutePrefix

[RoutePrefix("api/values")]
public class ValuesController : ApiController {
    //GET api/values/100/some-string-here
    [HttpGet]
    [Route("{p1}/{p2}")]
    public HttpResponseMessage Get (string p1, string p2) {
    ...
    }
}

Also if like in your example you want the first parameter to be an integer. then you can use a route constraint and update method.

[RoutePrefix("api/values")]
public class ValuesController : ApiController {
    //GET api/values/100/some-string-here
    [HttpGet]
    [Route("{p1:int}/{p2}")]
    public HttpResponseMessage Get (int p1, string p2) {
    ...
    }
}

UPDATE:

Created an integration test for the Values Controller and was able to confirm that the action was called

[TestMethod]
public async Task HttpClient_Should_Get_OKStatus_From_Action_With_Multiple_Parameters() {
    var config = new HttpConfiguration();
    config.MapHttpAttributeRoutes();

    using (var server = new HttpServer(config)) {

        var client = new HttpClient(server);

        string url = "http://localhost/api/values/100/some+string+here";

        using (var response = await client.GetAsync(url)) {
            Assert.AreEqual(HttpStatusCode.OK, response.StatusCode);
        }
    }
}