Single controller with multiple GET methods in ASP.NET Web API

In Web API I had a class of similar structure:

public class SomeController : ApiController
{
    [WebGet(UriTemplate = "{itemSource}/Items")]
    public SomeValue GetItems(CustomParam parameter) { ... }

    [WebGet(UriTemplate = "{itemSource}/Items/{parent}")]
    public SomeValue GetChildItems(CustomParam parameter, SomeObject parent) { ... }
}

Since we could map individual methods, it was very simple to get the right request at the right place. For similar class which had only a single GET method but also had an Object parameter, I successfully used IActionValueBinder. However, in the case described above I get the following error:

Multiple actions were found that match the request: 

SomeValue GetItems(CustomParam parameter) on type SomeType

SomeValue GetChildItems(CustomParam parameter, SomeObject parent) on type SomeType

I am trying to approach this problem by overriding the ExecuteAsync method of ApiController but with no luck so far. Any advice on this issue?

Edit: I forgot to mention that now I am trying to move this code on ASP.NET Web API which has a different approach to routing. The question is, how do I make the code work on ASP.NET Web API?

This is the best way I have found to support extra GET methods and support the normal REST methods as well. Add the following routes to your WebApiConfig:

routes.MapHttpRoute("DefaultApiWithId", "Api/{controller}/{id}", new { id = RouteParameter.Optional }, new { id = @"\d+" });
routes.MapHttpRoute("DefaultApiWithAction", "Api/{controller}/{action}");
routes.MapHttpRoute("DefaultApiGet", "Api/{controller}", new { action = "Get" }, new { httpMethod = new HttpMethodConstraint(HttpMethod.Get) });
routes.MapHttpRoute("DefaultApiPost", "Api/{controller}", new {action = "Post"}, new {httpMethod = new HttpMethodConstraint(HttpMethod.Post)});

I verified this solution with the test class below. I was able to successfully hit each method in my controller below:

public class TestController : ApiController
{
    public string Get()
    {
        return string.Empty;
    }

    public string Get(int id)
    {
        return string.Empty;
    }

    public string GetAll()
    {
        return string.Empty;
    }

    public void Post([FromBody]string value)
    {
    }

    public void Put(int id, [FromBody]string value)
    {
    }

    public void Delete(int id)
    {
    }
}

I verified that it supports the following requests:

GET /Test
GET /Test/1
GET /Test/GetAll
POST /Test
PUT /Test/1
DELETE /Test/1

Note That if your extra GET actions do not begin with 'Get' you may want to add an HttpGet attribute to the method.

Go from this:

config.Routes.MapHttpRoute("API Default", "api/{controller}/{id}",
            new { id = RouteParameter.Optional });

To this:

config.Routes.MapHttpRoute("API Default", "api/{controller}/{action}/{id}",
            new { id = RouteParameter.Optional });

Hence, you can now specify which action (method) you want to send your HTTP request to.

posting to "http://localhost:8383/api/Command/PostCreateUser" invokes:

public bool PostCreateUser(CreateUserCommand command)
{
    //* ... *//
    return true;
}

and posting to "http://localhost:8383/api/Command/PostMakeBooking" invokes:

public bool PostMakeBooking(MakeBookingCommand command)
{
    //* ... *//
    return true;
}

I tried this in a self hosted WEB API service application and it works like a charm :)

I find attributes to be cleaner to use than manually adding them via code. Here is a simple example.

[RoutePrefix("api/example")]
public class ExampleController : ApiController
{
    [HttpGet]
    [Route("get1/{param1}")] //   /api/example/get1/1?param2=4
    public IHttpActionResult Get(int param1, int param2)
    {
        Object example = null;
        return Ok(example);
    }

}

You also need this in your webapiconfig

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

config.Routes.MapHttpRoute(
    name: "ActionApi",
    routeTemplate: "api/{controller}/{action}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

Some Good Links http://www.asp.net/web-api/overview/getting-started-with-aspnet-web-api/tutorial-your-first-web-api This one explains routing better. http://www.asp.net/web-api/overview/web-api-routing-and-actions/routing-in-aspnet-web-api

You need to define further routes in global.asax.cs like this:

routes.MapHttpRoute(
    name: "Api with action",
    routeTemplate: "api/{controller}/{action}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);