Best way to convert Asp.Net MVC controllers to Web API

Question

I have this ASP.NET MVC 5 project which I'm converting over to AngularJS with MS Web Api.

Now in the old project I have these c# controllers of type Controller, however in my new project I've created some new Web Api controllers of type ApiController.

Now I'd like to reuse the old controller code in my new project. Herein lies my confusion.

As I attempt to port the old controller code over to my Web Api controller, I'm getting some front-end $http request errors.

Here's a function from my Angular dataService factory which makes an http req down to 'api/Whatif/SummaryPortfolios':

function getCurrPortfoliosLIst() {
  var deferred = $q.defer();

  var url = 'api/Whatif/SummaryPortfolios';
  var req={
    method: 'POST',
    url: url,
    headers: {
      'Content-Type': 'application/json',
    },
    data:{}
  };
  $http(req).then(function (resp){
    deferred.resolve(resp.data);
  }, function(err){
    console.log('Error from dataService: ' + resp);
  });
}

But the $http error section is returning this exception:

data: Object
ExceptionMessage: "Multiple actions were found that match the request: 
↵SummaryPortfolios on type MarginWorkbenchNG.Controllers.WhatifController
↵Post on type MarginWorkbenchNG.Controllers.WhatifController"
ExceptionType: "System.InvalidOperationException"
Message: "An error has occurred."
StackTrace: "   at System.Web.Http.Controllers.ApiControllerActionSelector.ActionSelectorCacheItem.SelectAction(HttpControllerContext controllerContext)
↵   at System.Web.Http.Controllers.ApiControllerActionSelector.SelectAction(HttpControllerContext controllerContext)
↵   at System.Web.Http.ApiController.ExecuteAsync(HttpControllerContext controllerContext, CancellationToken cancellationToken)
↵   at System.Web.Http.Dispatcher.HttpControllerDispatcher.<SendAsync>d__1.MoveNext()

Here's the c# API controller I'm calling down to, but I need to figure out how to create methods other than straight Get() and Post() methods:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web;
using System.Web.Http;
using Microsoft.AspNet.Identity;
using NLog;
using Microsoft.AspNet.Identity.Owin;
using MarginWorkbenchNG.Models;
using Rz.DAL;
using Rz.DAL.Integration;
using Rz.DAL.Models;
using Rz.DAL.Models.Rz;

namespace MarginWorkbenchNG.Controllers
{
    public class WhatifController : ApiController
    {
		public IEnumerable<string> Get()
			{						 
				return new string[] { "value1", "value2" };
			}
		[HttpPost]
        public List<WhatifSummaryViewModel> SummaryPortfolios(string filterValue = "", int? whatIfBatchNumber = null, bool includeBaseline = true)
        {
            // Get portfolios from Rz
            IEnumerable<Portfolio> portfolios = GetPortfolios(filterValue, whatIfBatchNumber, includeBaseline)
                .Where(x => x.PortfolioKeys.Any(k => k.Type == Settings.Whatif.SidebarPortfolioKey && k.DisplayValue == filterValue));

            // View Model
            List<WhatifSummaryViewModel> model = new List<WhatifSummaryViewModel> { };

            /// additional code here...

            return model;
        }
	}
}

The old controller (from the MVC5 project) looks slightly different of course because the _Summary method is of type ActionResult and returns a Partial:

public class WhatifController : Controller
    {
      
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult _Summary(string filterValue = "", int? whatIfBatchNumber = null, bool includeBaseline = true)
        {
            // Get portfolios from Razor
            IEnumerable<Portfolio> portfolios = GetPortfolios(filterValue, whatIfBatchNumber, includeBaseline)
                .Where(x => x.PortfolioKeys.Any(k => k.Type == Settings.Whatif.SidebarPortfolioKey && k.DisplayValue == filterValue));

            // View Model
            List<WhatifSummaryViewModel> model = new List<WhatifSummaryViewModel> { };

           // additional code removed for brevity...

            return PartialView(model.OrderBy(x => x.Title).ThenBy(x => x.SubTitle));
        }

My RouteConfig.cs :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace MarginWorkbenchNG
{
  public class RouteConfig
  {
    public static void RegisterRoutes(RouteCollection routes)
    {
      routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

      routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
      );
    }
  }
}

The old project also uses Html forms to pull the URL, for example:

 <form id="whatif-summary-form" action="@Url.Action("_Summary", "WhatIf")" method="POST"></form>

and then pulls the action attrib to get the URL when building out the ajax request in JavaScript (non-Angular) :

url: form.prop("action")

Answer 1

Is this your entire ApiController? The error message you are receiving is because your ApiController has several methods that are of the same type and it can't tell which one to route to. To test this: comment out all of your controller's methods except the one you are calling. You shouldn't receive that error anymore.

This is an easy fix, just tell web api how to map your route. Add the attribute '[Route("yourroute')]' to your method and it should work.

    public class WhatifController : ApiController
    {
        [HttpPost, Route("Your Route Goes here 'SummaryPortfolios'")]
        public IHttpActionResult SummaryPortfolios(string filterValue = "", int? whatIfBatchNumber = null, bool includeBaseline = true)
        {
            // Get portfolios from Rz
            IEnumerable<Portfolio> portfolios = GetPortfolios(filterValue, whatIfBatchNumber, includeBaseline)
                .Where(x => x.PortfolioKeys.Any(k => k.Type == Settings.Whatif.SidebarPortfolioKey && k.DisplayValue == filterValue));

            // View Model
            List<WhatifSummaryViewModel> model = new List<WhatifSummaryViewModel> { };

            /// additional code here...

            return Ok(model);
        }
    }