WebApi Action filter called twice - asp.net-mvc

My WebApi filter method OnActionExecuted is being called twice.
My filter (I make it as simple as possible):
public class NHibernateActionFilter : ActionFilterAttribute
{
// [Inject]
// public ISessionFactoryProvider sessionFactoryProvider { get; set; }
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
var a = 5;
var b = a;
//new BaseSessionProvider(sessionFactoryProvider).EndContextSession();
}
}
My setup:
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
//http://stackoverflow.com/questions/9521040/how-to-add-global-asp-net-web-api-filters
FilterConfig.RegisterWebApiFilters(GlobalConfiguration.Configuration.Filters);
}
public class FilterConfig
{
public static void RegisterWebApiFilters(System.Web.Http.Filters.HttpFilterCollection filters)
{
filters.Add(new NHibernateActionFilter());
}
}
In debugger I catch OnActionExecuted twice with the same actionExecutedContext. Why?
UPD
Controller
public class BankSmsController : ApiController
{
[AcceptVerbs(HttpVerbs.Get)]
public int GetTest()
{
return 1;
}
}

I have a suspicion, that this strange behavior can be fixed by either overriding AllowMultiple property of filter and returning false, or applying AttributeUsage attribute with AllowMultiple set to false too (this influences on default implementation of AllowMultiple property of filter.
At least in our project this helped (we have filters injected via Autofac).

This might be caused due to a registration of a custom filter provider. When you do this, you need to unregister the default one. Otherwise, if you are getting the usual filters in your custom one, they will be registered twice and consequently, executed twice.
Code should be something like this:
// remove default action filter provider
var defaultFilterProvider = config.Services.GetFilterProviders().Single(provider => provider is ActionDescriptorFilterProvider);
config.Services.Remove(typeof(IFilterProvider), defaultFilterProvider);
// add custom filter provider
config.Services.Add(typeof(IFilterProvider), new CustomFilterProvider(container));
As have been said, AllowMultiple to false is a hack since .net is clever enough to only execute once a filter even if it has been registered several times. Also, there are scenarios where you do need this to be true.

For me, I had specified the filter twice. In my IOC config file I had
builder.Register(c => new SelectListFilter(c.Resolve<ClientManager>()))
.AsActionFilterFor<Controller>()
.InstancePerRequest();
.RegisterFilterProvider();
And then in filterConfig I had
filters.Add(DependencyResolver.Current.GetService<IActionFilter>());
I removed the line from filterConfig and everything was better.

Related

Injecting dependencies into custom Web API action filter attribute with Autofac

I'm trying to resolve the dependencies of my custom AuthorizeAttribute which I use to decorate my API controllers in an MVC4 app. Problem is that I keep getting a NullReferenceException on the service dependency I use within my custom filter. Here is my Autofac configuration:
public static class WebApiConfig
{
public static void Register(HttpConfiguration config)
{
var builder = new ContainerBuilder();
builder.RegisterApiControllers(Assembly.GetExecutingAssembly());
builder.RegisterType<UnitOfWork>().As<IUnitOfWork>().InstancePerApiRequest();
builder.RegisterType<DatabaseFactory>().As<IDatabaseFactory>().InstancePerApiRequest();
builder.RegisterAssemblyTypes(typeof(UserProfileRepository).Assembly)
.Where(t => t.Name.EndsWith("Repository"))
.AsImplementedInterfaces().InstancePerApiRequest();
builder.RegisterAssemblyTypes(typeof(IUserProfileMapper).Assembly)
.Where(t => t.Name.EndsWith("Mapper"))
.AsImplementedInterfaces().InstancePerApiRequest();
builder.RegisterAssemblyTypes(typeof(UserProfileSvc).Assembly)
.Where(t => t.Name.EndsWith("Svc"))
.AsImplementedInterfaces().InstancePerApiRequest();
builder.RegisterWebApiFilterProvider(config);
var container = builder.Build();
var resolver = new AutofacWebApiDependencyResolver(container);
config.DependencyResolver = resolver;
}
}
and my custom authorize filter:
public class MyAuthorizeAttribute : AuthorizeAttribute
{
public IAuthenticationSvc _authenticationSvc;
protected override bool IsAuthorized(System.Web.Http.Controllers.HttpActionContext actionContext)
{
if (!base.IsAuthorized(actionContext))
{
return false;
}
var trueUserId = WebSecurity.CurrentUserId;
if (_authenticationSvc.GetUsersRoles(trueUserId).Any(x => x == "Admin")) return true;
// NullReferenceException on _authenticationSvc
}
}
According to the official docs all that is needed is:
var builder = new ContainerBuilder();
builder.RegisterWebApiFilterProvider(GlobalConfiguration.Configuration);
But that doesn't seem to do the trick either. Appreciate any help.
I think Autofac's documentation offers much simpler solution for WebApi action filters.
public interface ServiceCallActionFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(HttpActionContext actionContext)
{
// Get the request lifetime scope so you can resolve services.
var requestScope = actionContext.Request.GetDependencyScope();
// Resolve the service you want to use.
var service = requestScope.GetService(typeof(IMyService)) as IMyService;
// Do the rest of the work in the filter.
service.DoWork();
}
}
It is not "pure DI" as it is using service locator, but it is simple and works with the request scope. You don't need to worry about registering specific action filter for each WebApi controller.
Source:
http://autofac.readthedocs.io/en/latest/integration/webapi.html#provide-filters-via-dependency-injection
You should configure property injection for your attribute
public class MyAuthorizeAttribute : AuthorizeAttribute
{
public IAuthenticationSvc AuthenticationSvc { get; set; }
}
and the builder
builder.RegisterType<MyAuthorizeAttribute>().PropertiesAutowired();
In addition to #Toan Nguyen's answer, if you have this...
public class MyAuthorizeAttribute : AuthorizeAttribute
{
public IAuthenticationSvc AuthenticationSvc { get; set; }
}
... it seems you also need (or may need) the first line below:
builder.RegisterFilterProvider();
builder.RegisterType<MyAuthorizeAttribute>().PropertiesAutowired();
Reference: http://itprojectpool.blogspot.com.au/2014/03/autofac-di-on-action-filters.html
In addition to configuring property injection, as outlined in other answers, you can also explicitly resolve dependencies in the OnActivating callback.
public class MyAuthorizeAttribute : AuthorizeAttribute
{
private IAuthenticationSvc _authenticationSvc;
public void SetAuthenticationSvc(IAuthenticationSvc svc)
{
this._authenticationSvc = svc;
}
}
And then register the type:
builder.RegisterType<MyAuthorizeAttribute>()
.OnActivating(_ => _.Instance.SetAuthenticationSvc(_.Context.Resolve<IAuthenticationSvc>()));
Note: You can do the same with a property instead of a method. I chose to use a method here only to illustrate that this solution was not dependent on PropertiesAutowired.

Initialize BaseController's fields using HttpContext, controller design

I need to setup a policy in base controller that applies to all controller instance, like below:
public class BaseController : Controller
{
private IPolicy Policy;
public BaseController()
{
this.Policy= new Policy(HttpContext);
}
}
Within the Policy class, I need to do something like:
this.httpContextBase.User.
Questions: (Update)
What is the better way to design the BaseController in terms of using HttpContext and Unit test.
What is the correct way to unit test HttpContext?
Absolutely no way. You are using the HttpContext inside the constructor of a controller when this context is still not initialized. Not only that this code cannot be tested but when you run the application it will also crash with NRE. You should never use any HttpContext related stuff in a constructor of a controller.
One possibility is to refactor your code and perform this inside the Initialize method:
public class BaseController : Controller
{
private IPolicy Policy;
protected override void Initialize(RequestContext requestContext)
{
base.Initialize(requestContext);
this.Policy = new Policy(HttpContext);
}
}
This being said, that's not the approach I would recommend. I would recommend you using dependency injection instead of service location which is considered by many as an anti-pattern.
So:
public abstract class BaseController : Controller
{
protected IPolicy Policy { get; private set; }
protected BaseController(IPolicy policy)
{
Policy = policy;
}
}
Now, all that's left is to configure your favourite Dependency Injection framework to inject the correct instance into the constructor. For example with Ninject.Mvc3 this is achieved with a single line of code:
kernel.Bind<IPolicy>().To<Policy>();
Now you can feel more than free to mock this IPolicy in your unit test without even caring about any HttpContext.
For example let's suppose that you have the following controller that you want to unit test:
public class FooController : BaseController
{
public FooController(IPolicy policy): base(policy)
{ }
[Authorize]
public ActionResult Index()
{
Policy.DoSomething();
return View();
}
}
Now, all that you need to do is pick up your favorite mock framework (Rhino Mocks in my case) and do the mocking:
[TestMethod]
public void Index_Action_Should_DoSomething_With_The_Policy()
{
// arrange
var policyStub = MockRepository.GenerateStub<IPolicy>();
var sut = new FooController(policyStub);
// act
var actual = sut.Index();
// assert
Assert.IsInstanceOfType(actual, typeof(ViewResult));
policyStub.AssertWasCalled(x => x.DoSomething());
}

Property injection in my custom attribute?

We are using StructureMap as container in my current project and all has been working well until we had to inject dependencies to a custom attribute we are using.
First, code for registering stuff in the container would look like this...
Container = new Container();
Registry = new Registry();
ServiceLocator = new StructureMapServiceLocator(Container);
Registry.For<IServiceLocator>().Use(ServiceLocator);
Registry.For<IHitCounter>().Add<HitCounter>();
Registry.For<IHitCountAttribute>().Use<HitCountAttribute>();
Registry.SetAllProperties(policy => policy.OfType<IHitCounter>());
Container.Configure(config => config.AddRegistry(Registry));
The kind of registering above do work for a normal class with setter injection (and constructor injection) but obviously not for an attribute class.
An attribute class could look like this...
public class HitCountAttribute : ActionFilterAttribute, IHitCountAttribute
{
public IHitCounter HitCounter { get; set; }
public override void OnResultExecuted(ResultExecutedContext filterContext)
{
HitCounter.Count(HttpContext.Current.Request.Url.ToString());
base.OnResultExecuted(filterContext);
}
}
The interface look like this...
public interface IHitCountAttribute
{
IHitCounter HitCounter { get; set; }
void OnResultExecuted(ResultExecutedContext filterContext);
}
Is it even possible to inject dependencies to an attribute? As it is instantiated by the runtime...
Is there any other way to solve the problem with the dependencies?

A way to exclude action filters in ASP.NET MVC?

I've run into several cases in ASP.NET MVC where I wanted to apply an action filter on every action except one or two. For example, say you have an AccountController. Every action in it requires the user be logged in, so you add [Authorize] at the controller level. But say you want to include the login page in AccountController. The problem is, users sent to the login page aren't authorized, so this would result in an infinite loop.
The obvious fix (other than moving the Login action to another controller) is to move the [Authorize] from the controller to all action methods except Login. Well that ain't fun, especially when you have a lot of methods or forget to add [Authorize] to a new method.
Rails makes this easy with an ability to exclude filters. ASP.NET MVC doesn't let you. So I decided to make it possible and it was easier than I thought.
/// <summary>
/// This will disable any filters of the given type from being applied. This is useful when, say, all but on action need the Authorize filter.
/// </summary>
[AttributeUsage(AttributeTargets.Method|AttributeTargets.Class, AllowMultiple=true)]
public class ExcludeFilterAttribute : ActionFilterAttribute
{
public ExcludeFilterAttribute(Type toExclude)
{
FilterToExclude = toExclude;
}
/// <summary>
/// The type of filter that will be ignored.
/// </summary>
public Type FilterToExclude
{
get;
private set;
}
}
/// <summary>
/// A subclass of ControllerActionInvoker that implements the functionality of IgnoreFilterAttribute. To use this, just override Controller.CreateActionInvoker() and return an instance of this.
/// </summary>
public class ControllerActionInvokerWithExcludeFilter : ControllerActionInvoker
{
protected override FilterInfo GetFilters(ControllerContext controllerContext, ActionDescriptor actionDescriptor)
{
//base implementation does all the hard work. we just prune off the filters to ignore
var filterInfo = base.GetFilters(controllerContext, actionDescriptor);
foreach( var toExclude in filterInfo.ActionFilters.OfType<ExcludeFilterAttribute>().Select(f=>f.FilterToExclude).ToArray() )
{
RemoveWhere(filterInfo.ActionFilters, filter => toExclude.IsAssignableFrom(filter.GetType()));
RemoveWhere(filterInfo.AuthorizationFilters, filter => toExclude.IsAssignableFrom(filter.GetType()));
RemoveWhere(filterInfo.ExceptionFilters, filter => toExclude.IsAssignableFrom(filter.GetType()));
RemoveWhere(filterInfo.ResultFilters, filter => toExclude.IsAssignableFrom(filter.GetType()));
}
return filterInfo;
}
/// <summary>
/// Removes all elements from the list that satisfy the condition. Returns the list that was passed in (minus removed elements) for chaining. Ripped from one of my helper libraries (where it was a pretty extension method).
/// </summary>
private static IList<T> RemoveWhere<T>(IList<T> list, Predicate<T> predicate)
{
if (list == null || list.Count == 0)
return list;
//note: didn't use foreach because an exception will be thrown when you remove items during enumeration
for (var i = 0; i < list.Count; i++)
{
var item = list[i];
if (predicate(item))
{
list.RemoveAt(i);
i--;
}
}
return list;
}
}
/// <summary>
/// An example of using the ExcludeFilterAttribute. In this case, Action1 and Action3 require authorization but not Action2. Notice the CreateActionInvoker() override. That's necessary for the attribute to work and is probably best to put in some base class.
/// </summary>
[Authorize]
public class ExampleController : Controller
{
protected override IActionInvoker CreateActionInvoker()
{
return new ControllerActionInvokerWithExcludeFilter();
}
public ActionResult Action1()
{
return View();
}
[ExcludeFilter(typeof(AuthorizeAttribute))]
public ActionResult Action2()
{
return View();
}
public ActionResult Action3()
{
return View();
}
}
The example is right there. As you can see, this was pretty straightforward to do and works great. I hope it's useful to anyone?
I prefer the solution outlined here. Though it's not as generic a solution as yours, I found it a bit more straightforward.
In my case, I was looking for a way to enable a CompressionFilter on everything but a few items. So I created an empty attribute like this:
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public sealed class DisableCompression : Attribute { }
Then in the main attribute, check for the presence of the attribute like so:
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false)]
public class CompressionFilter : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
bool disabled = filterContext.ActionDescriptor.IsDefined(typeof(DisableCompression), true) ||
filterContext.ActionDescriptor.ControllerDescriptor.IsDefined(typeof(DisableCompression), true);
if (disabled)
return;
// action filter logic here...
}
}
Though the page I linked to mentions that this is for MVC 3, it seems to work well enough way back in MVC 1 as well.
EDIT: showing some usage here in response to comments. Before I made the changes above, it looked exactly like this, except without the [DisableCompression] attribute flagging the method I wanted to exclude. There's no other refactoring involved.
[CompressionFilter]
public abstract class BaseController : Controller
{
}
public class SomeController : BaseController
{
public ActionResult WantThisActionCompressed()
{
// code
}
[DisableCompression]
public ActionResult DontWantThisActionCompressed()
{
// code
}
}
I assume for years ago that the [AllowAnnonymous] attribute hadn't been added to ASP.NET MVC. Today I can have the [Authorize] attribute on top of my controller applying to all the Action methods and I just simply override this in Actions I require unauthorized users by adding the [AllowAnonymous] attributes to the specific actions.

ASP.NET MVC: Ignore custom attribute in a base controller class

I have a number of Controllers in my project that all inherit from a controller I've named BaseController. I wrote a custom attribute that I applied to the entire BaseController class, so that each time an action runs in any of my controllers, that attribute will run first.
The problem is that I have a couple of controller actions that I'd like to ignore that attribute, but I don't know how to do it.
Can anyone help? I'm using MVC 1.
Thanks.
In your custom attribute, you can add this ShouldRun() check like this:
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (ShouldRun(filterContext))
{
// proceed with your code
}
}
private bool ShouldRun(ActionExecutingContext filterContext)
{
var ignoreAttributes = filterContext.ActionDescriptor.GetCustomAttributes(typeof(IgnoreMyCustomAttribute), false);
if (ignoreAttributes.Length > 0)
return false;
return true;
}
ShouldRun() simply checks whether there's a "IgnoreMyCustomAttribute" on your action. If it's there, then your custom attribute won't do anything.
You'll now want to create a simple IgnoreMyCustomAttribute, which doesn't do anything:
[AttributeUsage(AttributeTargets.Method, AllowMultiple = false)]
public class IgnoreMyCustomAttribute: ActionFilterAttribute
{
}
Whenever you decorate your controller action with [IgnoreMyCustom], then MyCustomAttribute won't do anything. e.g.:
[IgnoreMyCustom]
public ViewResult MyAction() {
}
I had a similar need for something like this and found that by creating an authorization filter (implementing/deriving from FilterAttribute, IAuthorizationFilter) rather than a regular action filter (deriving from ActionFilterAttribute), and setting Inherited=true and AllowMultiple=false on the attribute, that it would only run once at the appropriate spot.
This means I am able to "cascade" my filter down from a base controller (the site-wide default), to a derived controller (for example the AdminController or whatever), or even further down to an individual action method.
For example,
[AttributeUsage(AttributeTargets.Class|AttributeTargets.Method, Inherited=true, AllowMultiple=false)]
public class MyCustomAttribute : FilterAttribute, IAuthorizationFilter
{
private MyCustomMode _Mode;
public MyCustomAttribute(MyCustomMode mode)
{
_Mode = mode;
}
public virtual void OnAuthorization(AuthorizationContext filterContext)
{
if (filterContext == null)
{
throw new ArgumentNullException("filterContext");
}
// run my own logic here.
// set the filterContext.Result to anything non-null (such as
// a RedirectResult?) to skip the action method's execution.
//
//
}
}
public enum MyCustomMode
{
Enforce,
Ignore
}
And then to use it, I can apply it to my super-controller,
[MyCustomAttribute(Ignore)]
public class BaseController : Controller
{
}
And I can change/override it for specific controllers, or even for specific actions!
[MyCustomAttribute(Enforce)]
public class AdministrationController : BaseController
{
public ActionResult Index()
{
}
[MyCustomAttribute(Ignore)]
public ActionResult SomeBasicPageSuchAsAHelpDocument()
{
}
}
This allowed me to "turn off" the filter for specific cases, while still being able to apply it as a default on either the whole controller or whole application.
Good luck!
I'm not sure there is an easy way to remove attributes in this situation. But I have done something similar for a project and what I did, as it was only in a few instances I didn't want my attribute to run, was to create two attributes.
My first attribute was applied to my base controller as you've done but it was aware of the existance of a second attribute and by implementing that second attribute I could disable the attribute on the base class from running.
Not sure if it was the best solution but it worked for me.
This was applied to the base controller:
/// <summary>
/// This is used to force the schema to HTTP is it is HTTPS.
/// RequireHttpsAttribute or OptionalHttpsAttribute takes precedence if used.
/// </summary>
public class RequireHttpAttribute : FilterAttribute, IAuthorizationFilter
{
public virtual void OnAuthorization(AuthorizationContext filterContext)
{
if (filterContext == null)
throw new ArgumentNullException("filterContext");
if (filterContext.HttpContext.Request.IsSecureConnection)
{
object[] attributes = filterContext.ActionDescriptor.GetCustomAttributes(true);
if (!attributes.Any(a => a is RequireHttpsAttribute || a is OptionalHttpsAttribute))
{
HandleHttpsRequest(filterContext);
}
}
}
protected virtual void HandleHttpsRequest(AuthorizationContext filterContext)
{
// only redirect for GET method, otherwise browser may not propogate the verb and request body correctly
if (!string.Equals(filterContext.HttpContext.Request.HttpMethod, "GET", StringComparison.OrdinalIgnoreCase))
throw new InvalidOperationException(MvcResources.RequireHttpAttribute_MustNotUseSsl);
// redirect to HTTP version
string url = "http://" + filterContext.HttpContext.Request.Url.Host + filterContext.HttpContext.Request.RawUrl;
filterContext.Result = new RedirectResult(url);
}
}
Like so:
[RequireHttp]
public abstract class Controller : System.Web.Mvc.Controller
{
}
I could then use what is effectively a dummy attribute to disable it.
/// <summary>
/// This attribute allows the action to be server on HTTP and HTTPS but neither is enforce.
/// RequireHttpsAttribute takes precedence if used.
/// </summary>
public class OptionalHttpsAttribute : FilterAttribute
{
// This is deliberately empty, the attribute is used by RequireHttpAttribute to stop it changing schema to HTTP
}
Like so:
[OptionalHttps]
public ActionResult OptionalHttps()
{
return View();
}

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