Autofac automatically generates factories for Func<T>; I can even pass parameters.
public class MyClass
{
public MyClass(Func<A> a, Func<int, B> b)
{
var _a = a();
var _b = b(1);
}
}
Can I do the same with Ninject? If not, what workaround can I apply?
Thanks.
Update:
Just found this post, seems the answer is no:
How do I handle classes with static methods with Ninject?
NB Ninject 3.0 and later has this fully supported using the Ninject.Extensions.Factory package, see the wiki:- https://github.com/ninject/ninject.extensions.factory/wiki
EDIT: NB there is a Bind<T>().ToFactory() implementation in Ninject 2.3 (which is not a fully tests supported release but is available from the CodeBetter server)
Ninject does not support this natively at the moment. We planned to add this to the next version. But support can be added easily by configuring the appropriate binding. Just load the module below and enjoy.
public class FuncModule : NinjectModule
{
public override void Load()
{
this.Kernel.Bind(typeof(Func<>)).ToMethod(CreateFunc).When(VerifyFactoryFunction);
}
private static bool VerifyFactoryFunction(IRequest request)
{
var genericArguments = request.Service.GetGenericArguments();
if (genericArguments.Count() != 1)
{
return false;
}
var instanceType = genericArguments.Single();
return request.ParentContext.Kernel.CanResolve(new Request(genericArguments[0], null, new IParameter[0], null, false, true)) ||
TypeIsSelfBindable(instanceType);
}
private static object CreateFunc(IContext ctx)
{
var functionFactoryType = typeof(FunctionFactory<>).MakeGenericType(ctx.GenericArguments);
var ctor = functionFactoryType.GetConstructors().Single();
var functionFactory = ctor.Invoke(new object[] { ctx.Kernel });
return functionFactoryType.GetMethod("Create").Invoke(functionFactory, new object[0]);
}
private static bool TypeIsSelfBindable(Type service)
{
return !service.IsInterface
&& !service.IsAbstract
&& !service.IsValueType
&& service != typeof(string)
&& !service.ContainsGenericParameters;
}
public class FunctionFactory<T>
{
private readonly IKernel kernel;
public FunctionFactory(IKernel kernel)
{
this.kernel = kernel;
}
public Func<T> Create()
{
return () => this.kernel.Get<T>();
}
}
}
Related
I can't find IHttpControllerActivator in asp.net core api
public class WindsorHttpControllerActivator:IHttpControllerActivator
{
public IHttpController Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
{
var instance = DependencyContainer.Resolve(controllerType);
if (instance == null)
{
throw new HttpException((int)HttpStatusCode.NotFound, string.Format("{0} cannot be resolved.", controllerType.Name));
}
return (IHttpController) instance;
}
}
Let me know if this rewrite works.
There were changes to the API for third-party DI
using Castle.Windsor;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Controllers;
public class WindsorControllerActivator : IControllerActivator
{
private readonly IWindsorContainer _container;
public WindsorControllerActivator(IWindsorContainer container)
{
_container = container;
}
public object Create(ControllerContext context)
{
var controllerType = context.ActionDescriptor.ControllerTypeInfo.AsType();
var instance = _container.Resolve(controllerType);
if (instance == null)
{
//throw whatever
}
return (ControllerBase)instance;
}
public void Release(ControllerContext context, object controller)
{
_container.Release(controller);
}
}
these articles were helpful to me # least:
https://kristian.hellang.com/third-party-dependency-injection-in-asp-net-core/
https://medium.com/#nevsnirG/manual-controller-activation-and-dependency-injection-in-asp-net-core-web-api-46aba579b0e
EDIT:
in '''Startup.cs''', don't forget the lines
services.AddSingleton<IControllerActivator>(new WindsorControllerActivator (_container));
I'm creating a custom model binder for a view model, implementing IModelBinder
I have a lot of properties in my view model, the majority of which do not need any custom binding. Rather than explicitly set all of the property values on my model individually from the ModelBindingContext, I would to be able to get the framework to bind the model for me, then I would carry out any custom binding:
public class ApplicationViewModelBinder : IModelBinder
{
public Task BindModelAsync(ModelBindingContext bindingContext)
{
if (bindingContext == null)
{
throw new ArgumentNullException(nameof(bindingContext));
}
// get .net core to bind values on model
// Cary out any customization of the models properties
bindingContext.Result = ModelBindingResult.Success(bindingContext.Model);
return Task.CompletedTask;
}
}
Basically I want to carry out the default model binding, then apply custom binding, similar to the approach taken in this SO post but for .NET Core, not framework.
I assumed applying the default binding would be straight forward, but haven't been able to find out how to do so. I believe the solution would involve ComplexTypeModelBinder and ComplexTypeModelBinderProvider classes, but can't seem to find out how to go about it.
I know I could just make any changes when the POST request hits my controller method, but this seem the wrong place and wrong time to do so.
For custom ComplexTypeModelBinder, you could inherit from ComplexTypeModelBinder.
Model
public class BinderModel
{
public int Id { get; set; }
public string Name { get; set; }
public string BinderValue { get; set; }
}
Controller Action
[HttpPost]
public void Post([FromForm]BinderModel value)
{
}
CustomBinder
public class CustomBinder : ComplexTypeModelBinder
{
private readonly IDictionary<ModelMetadata, IModelBinder> _propertyBinders;
public CustomBinder(IDictionary<ModelMetadata, IModelBinder> propertyBinders)
: base(propertyBinders)
{
_propertyBinders = propertyBinders;
}
protected override Task BindProperty(ModelBindingContext bindingContext)
{
if (bindingContext.FieldName == "BinderValue")
{
bindingContext.Result = ModelBindingResult.Success("BinderValueTest");
return Task.CompletedTask;
}
else
{
return base.BindProperty(bindingContext);
}
}
protected override void SetProperty(ModelBindingContext bindingContext, string modelName, ModelMetadata propertyMetadata, ModelBindingResult result)
{
base.SetProperty(bindingContext, modelName, propertyMetadata, result);
}
}
CustomBinderProvider
public class CustomBinderProvider : IModelBinderProvider
{
public IModelBinder GetBinder(ModelBinderProviderContext context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (context.Metadata.IsComplexType && !context.Metadata.IsCollectionType)
{
var propertyBinders = new Dictionary<ModelMetadata, IModelBinder>();
for (var i = 0; i < context.Metadata.Properties.Count; i++)
{
var property = context.Metadata.Properties[i];
propertyBinders.Add(property, context.CreateBinder(property));
}
//var loggerFactory = context.Services.GetRequiredService<ILoggerFactory>();
//return new ComplexTypeModelBinder(propertyBinders, loggerFactory);
return new CustomBinder(propertyBinders);
}
return null;
}
}
Inject provider
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc(options => {
options.ModelBinderProviders.Insert(0, new CustomBinderProvider());
});
}
ComplexTypeModelBinder has unfortunately been deprecated in .Net 5.0, and it's counterpart, ComplexObjectModelBinder, is sealed, so you can't extend from it.
But, you can work around that. ComplexObjectModelBinderProvider is public, and you can use that to create a ComplexObjectModelBinder. Thus, if you make your own custom IModelBinderProvider, you can have the constructor accept a ComplexObjectModelBinderProvider argument, and make use of that to make a ComplexObjectModelBinder. Then, you can pass that to your custom IModelBinder, where it'll happily do its custom work before falling back to the ComplexObjectModelBinder you supplied.
Here's an example. First, your IModelBinder. This example shows that you can use DI if you want to. (In this example, say we needed a DbContext.)
public class MyCustomModelBinder : IModelBinder
{
private readonly IModelBinder _defaultBinder;
private readonly DbContext _dbContext;
public MyCustomModelBinder(IModelBinder defaultBinder, DbContext dbContext)
{
_defaultBinder = defaultBinder;
_dbContext = dbContext;
}
public override Task BindModelAsync(ModelBindingContext bindingContext)
{
// -do custom work here-
return _defaultBinder.BindModelAsync(bindingContext);
}
}
However, in order to use DI on your custom model binder, you'll need a helper class. The problem is, when IModelBinderProvider is called, it won't have access to all the services in a typical request, like your DbContext for example. But this class will help:
internal class DIModelBinder : IModelBinder
{
private readonly IModelBinder _rootBinder;
private readonly ObjectFactory _factory;
public DIModelBinder(Type binderType, IModelBinder rootBinder)
{
if (!typeof(IModelBinder).IsAssignableFrom(binderType))
{
throw new ArgumentException($"Your binderType must derive from IModelBinder.");
}
_factory = ActivatorUtilities.CreateFactory(binderType, new[] { typeof(IModelBinder) });
_rootBinder = rootBinder;
}
public Task BindModelAsync(ModelBindingContext bindingContext)
{
var requestServices = bindingContext.HttpContext.RequestServices;
var binder = (IModelBinder)_factory(requestServices, new[] { _rootBinder });
return binder.BindModelAsync(bindingContext);
}
}
Now you're ready to write the custom IModelBinderProvider:
public class MyCustomModelBinderProvider : IModelBinderProvider
{
private readonly IModelBinderProvider _rootProvider;
public MyCustomModelBinderProvider(IModelBinderProvider rootProvider)
{
_rootProvider = rootProvider;
}
public IModelBinder? GetBinder(ModelBinderProviderContext context)
{
if (context.Metadata.ModelType == typeof(MyModel))
{
var rootBinder = _rootProvider.GetBinder(context)
?? throw new InvalidOperationException($"Root {_rootProvider.GetType()} did not provide an IModelBinder for MyModel.");
return new DIModelBinder(typeof(MyCustomModelBinder), rootBinder);
}
return null;
}
}
Finally, in your startup file where you configure services, you can grab the ComplexObjectModelBinderProvider instance, use that to create a new instance of your MyCustomModelBinderProvider, and insert that into the ModelBinderProviders.
services.AddMvc(options =>
{
var fallbackProvider = options.ModelBinderProviders
.First(p => p is ComplexObjectModelBinderProvider);
var myProvider = new MyCustomModelBinderProvider(fallbackProvider);
options.ModelBinderProviders.Insert(0, myProvider);
})
Is it possible to change the default object scope in Ninject 2.2? If so, how is it done?
As far as I can tell you could override AddBinding() on the BindingRoot (StandardKernel or NinjectModule) and modify the ScopeCallback property on the binding object.
public class CustomScopeKernel : StandardKernel
{
public CustomScopeKernel(params INinjectModule[] modules)
: base(modules)
{
}
public CustomScopeKernel(
INinjectSettings settings, params INinjectModule[] modules)
: base(settings, modules)
{
}
public override void AddBinding(IBinding binding)
{
// Set whatever scope you would like to have as the default.
binding.ScopeCallback = StandardScopeCallbacks.Singleton;
base.AddBinding(binding);
}
}
This test should now pass (using xUnit.net)
public class DefaultScopedService { }
[Fact]
public void Should_be_able_to_change_default_scope_by_overriding_add_binding()
{
var kernel = new CustomScopeKernel();
kernel.Bind<DefaultScopedService>().ToSelf();
var binding = kernel.GetBindings(typeof(DefaultScopedService)).First();
binding.ScopeCallback.ShouldBe(StandardScopeCallbacks.Singleton);
}
The CustomScopeKernel will also work with Ninject modules.
public class ServiceModule : NinjectModule
{
public override void Load()
{
Bind<DefaultScopedService>().ToSelf();
}
}
[Fact]
public void Should_be_able_to_change_default_scope_for_modules()
{
var module = new ServiceModule();
var kernel = new CustomScopeKernel(module);
var binding = kernel.GetBindings(typeof(DefaultScopedService)).First();
binding.ScopeCallback.ShouldBe(StandardScopeCallbacks.Singleton);
}
Let's say I am using the new WCF Web API to build a RESTful service and, in my service, I have a section of the URI that will describe the target resource, but is used on (nearly) all methods of the contract. For example, if I have a User service that deals with eCommerce and may look like:
[ServiceContract]
public class MyUserService
{
private MyUserRepository _UserRepo;
private MyOrganizationRepository _OrgRepo;
[WebGet (UriTemplate = "{OrganizationName}/Users")]
public IEnumerable<User> GetUsers (string OrganizationName)
{
IEnumerable<User> Users = null;
var Organization = _OrgRepo.GetOrgByName (OrganizationName);
if (Organization != null)
{
Users = Organization.GetUsers ();
}
else
{
throw new WebFaultException<string> ("Organization not found.", HttpStatusCode.NotFound);
}
return Users;
}
[WebInvoke (UriTemplate = "{OrganizationName}/Users", /*yada...yada...yada*/)]
public User AddNewUser (string OrganizationName, User User)
{
// Find the organization, like above, and throw if null.
}
}
If I have to continually load the organization and test for null, this will bog down my code and is not very DRY. (So tempted to spell out DRY...) What I would like to do is load up a property in the MyUserService class that is populated when {OrganizationName} is included in the URI and throw a WebFaultException otherwise. Because this is apart of the URI, what would be the best way to accomplish this?
EDIT:
For those that may be interested, here is an example of the HttpOperationHandler I came up with. There doesn't seem to be a whole lot of information out there covering this. I also found more information about Processors that will be coming with the WCF Web Api suite and it looks like they will handle this sort of thing better replace HttpOperationHandlers and it seems they may be easier to use. (This is just a for-instance to cover some things I found hard to find. I wrote it up a bit differently in my application.)
using Microsoft.ApplicationServer.Http.Dispatcher; // For HttpOperationHandler
using Microsoft.ApplicationServer.Http.Description; // For HttpOperationHandlerFactory
public class OrganizationHandler : HttpOperationHandler<string, Organization>
{
private Repository<Organization> _OrganizationRepository;
public OrganizationHandler (UnitOfWork Work)
: base ("OrganizationName")
{
_OrganizationRepository = Work.Organizations;
}
public override Organization OnHandle (string OrganizationName)
{
var Result = _OrganizationRepository
.Get (O => O.UrlSafeName.Equals (OrganizationName,
StringComparison.InvariantCultureIgnoreCase));
if (Result == null)
{
throw new WebFaultException<string> ("Organization not found.");
}
return Result;
}
}
public class OrganizationHandlerFactory : HttpOperationHandlerFactory
{
private UnitOfWork _Work;
public OrganizationHandlerFactory (UnitOfWork Work)
{
_Work = Work;
}
protected override Collection<HttpOperationHandler> OnCreateRequestHandlers
(ServiceEndpoint endpoint, HttpOperationDescription operation)
{
var Collection = base.OnCreateRequestHandlers (endpoint, operation);
if (operation.InputParameters.Any (IP => IP.Type.Equals (typeof (Organization))))
{
var Binding = endpoint.Binding as HttpBinding;
if (Binding != null)
{
Collection.Add (new OrganizationHandler (_Work));
}
}
return Collection;
}
}
And then to wire it up in Global.asax (I am using Ninject for IoC):
// Add this reference to get the MapServiceRoute<T> extension
using Microsoft.ApplicationServer.Http.Activation;
public class Global : HttpApplication
{
protected void Application_Start (object sender, EventArgs e)
{
var Kernel = BuildKernel ();
var Config = HttpHostConfiguration.Create ()
.SetOperationHandlerFactory
(Kernel.Get (typeof (OrganizationHandlerFactory)) as OrganizationHandlerFactory)
.SetResourceFactory (new NinjectResourceFactory (Kernel));
RouteTable.Routes.MapServiceRoute<OrganizationService> ("Organizations", Config);
}
protected IKernel BuildKernel ()
{
IKernel Kernel = new Ninject.StandardKernel ();
// Load up the Kernel
return Kernel;
}
}
public class NinjectResourceFactory : IResourceFactory
{
private readonly IKernel _Kernel;
public NinjectResourceFactory (IKernel Kernel)
{
_Kernel = Kernel;
}
public object GetInstance (Type serviceType, InstanceContext instanceContext, HttpRequestMessage request)
{
return Resolve (serviceType);
}
public void ReleaseInstance (InstanceContext instanceContext, object service)
{
throw new NotImplementedException ();
}
private object Resolve (Type type)
{
return _Kernel.Get (type);
}
}
And here it is in my Service:
[ServiceContract]
[ServiceBehavior (InstanceContextMode = InstanceContextMode.PerCall)]
public class OrganizationService
{
[WebGet (UriTemplate = "{OrganizationName}/Products")]
public IEnumerable<Product> GetProducts (Organization Organization)
{
return Organization.Products;
}
}
This is exactly what OperationHandlers are for. You create a single OperationHandler that converts the URI parameter into a strongly typed object that you can just accept as a parameter on the operation.
Does anyone have an implementation lying around of an auto-mock container using Rhino Mocks and NInject?
OK I built one myself using the Moq integration as a starting point. It is very simple. You need these 3 classes:
public class AutoMockingKernel : StandardKernel
{
private readonly IMockProvider _mockProvider;
public void Reset()
{
Components.Get<ICache>().Clear();
}
protected override bool HandleMissingBinding(Type service)
{
var isSelfBindable = TypeIsSelfBindable(service);
var binding = new Binding(service)
{
ProviderCallback = isSelfBindable
? StandardProvider.GetCreationCallback(service)
: _mockProvider.GetCreationCallback(),
IsImplicit = true
};
if (!isSelfBindable)
binding.ScopeCallback = ctx => null;
AddBinding(binding);
return true;
}
public AutoMockingKernel(IMockProvider mockProvider, INinjectSettings settings, params INinjectModule[] modules)
: base(settings, modules)
{
_mockProvider = mockProvider;
}
public AutoMockingKernel(IMockProvider mockProvider, params INinjectModule[] modules)
: base(modules)
{
_mockProvider = mockProvider;
}
}
internal class RhinoMockProvider : IProvider
{
public Type Type { get; private set; }
/// <summary>
/// Initializes a new instance of the <see cref="RhinoMockProvider"/> class.
/// </summary>
public RhinoMockProvider(Type type)
{
Type = type;
}
public object Create(IContext context)
{
return MockRepository.GenerateMock(Type, Type.EmptyTypes);
}
}
public class RhinoAutoMockProvider : IMockProvider
{
public Func<IContext, IProvider> GetCreationCallback()
{
return ctx => new RhinoMockProvider(ctx.Request.Service);
}
}
You can then create an auto-mocking kernel in your unit test like this:
[Test]
public void Test()
{
var kernel = new AutoMockingKernel(new RhinoAutoMockProvider());
... etc
}
There is a RhinoMocks integration extension available.