Adding Ninject to WebAPI

Adding Ninject to WebAPI

1. Create a new WebApi project
2. Install the Ninject.MVC3 NuGet package which will in turn 
   install the Ninject, and Ninject.Web.Common NuGet packages
3. Create a Ninject Folder
4. Create a NinjectResolver.cs class as shown below

   using System.Web.Http.Dependencies;
   using Ninject;

   namespace MyNampespace
   {
      public class NinjectResolver : NinjectScope, IDependencyResolver
      {
         private IKernel kernel;
    
         public NinjectResolver(IKernel kernel)
            : base(kernel)
         {
            this.kernel = kernel;
         }
    
         public IDependencyScope BeginScope()
         {
            return new NinjectScope(kernel);
         }
      }
   }

5. Next create a NinjectScope.cs class as shown below

   using System;
   using System.Collections.Generic;
   using System.Linq;
   using System.Web.Http.Dependencies;
   using Ninject.Activation;
   using Ninject.Parameters;
   using Ninject.Syntax;
   
   namespace MyNamespace
   {
      public class NinjectScope : IDependencyScope
      {
         protected IResolutionRoot resolutionRoot;
   
         public NinjectScope(IResolutionRoot kernel)
         {
            resolutionRoot = kernel;
         }
   
         public object GetService(Type serviceType)
         {
            IRequest request = resolutionRoot.CreateRequest(serviceType, null, 
               new Parameter[0], true, true);
            return resolutionRoot.Resolve(request).SingleOrDefault();
         }
   
         public IEnumerable<object> GetServices(Type serviceType)
         {
            IRequest request = resolutionRoot.CreateRequest(serviceType, null,
               new Parameter[0], true, true);
            return resolutionRoot.Resolve(request).ToList();
         }
   
         public void Dispose()
         {
         }
      }
   }

6. Create a ICustomerRepository.cs interface

    namespace WebApi.Helpers
    {
        public interface ICustomerRepository
        {
            IEnumerable<string> GetCustomers();
        }
    }

7. Create a CustomerRepository.cs class

    namespace WebApi.Helpers
    {
        public class CustomerRepository : ICustomerRepository
        {
            public IEnumerable<string> GetCustomers()
            {
                return new List<string> { "CustomerA", "CustomerB"};
            }
        }
    }

8. Create a ServiceModule.cs to hold the bindings as shown below example.

    using Ninject.Modules;
    
    namespace MyNamespace
    {
        public class ServiceModule : NinjectModule
        {
            public override void Load()
            {
                Bind<ICustomerRepository>().To<CustomerRepository>().InSingletonScope();
            }
        }
    }

9. If you may have noticed under the App_Start folder Ninject created a class called
   NinjectWebCommon.cs. This is where Ninject wires up the Module(s) and directs WebApi
   on how to interact with them. There are only a couple of modifications we need to 
   make to this class, as shown below.

   //Add after private static readonly Bootstrapper bootstrapper = new Bootstrapper();
   public static IKernel Kernel { get { return bootstrapper.Kernel; } }
    
   //Add to the private static void RegisterServices(IKernel kernel) method
   kernel.Load<ServiceModule>();

10. Next, go into the Global.asax.cs file and copy in the following line at the end of
    the Application_Start method 

   GlobalConfiguration.Configuration.DependencyResolver = new NinjectResolver(NinjectWebCommon.Kernel);

11. Now you have Ninject all setup, the following sample controller shows how we use DI.

   using System.Net;
   using System.Net.Http;
   using System.Web.Http;
   using WebApi.Helpers;

   namespace WebApi.Controllers
   {
      public class CustomerController : ApiController
      {
         private readonly ICustomerRepository _customerRepository;
         
         public CustomerController(ICustomerRepository customerRepository)
         {
            _customerRepository = customerRepository;
         }
         
         public HttpResponseMessage Get()
         {
            var customers = _customerRepository.GetCustomers();
            
            return Request.CreateResponse(HttpStatusCode.OK, customers);
         }
      }
   }

Thank you very much. That gist finally gave me the answer I was looking for!

Any chance this ever gets included out of the box to the Ninject nuget package ?