Why is my ASP.NET Web API ActionFilterAttribute OnActionExecuting not firing?

Question

I'm trying to implement what's seen here: http://www.piotrwalat.net/nhibernate-session-management-in-asp-net-web-api/ but I'm having an issue with my NhSessionManagementAttribute.

I've set breakpoints on my OnActionExecuting(HttpActionContext actionContext) to see whether the function was ever being called -- it wasn't.

I double-checked my global.asax.cs file & found I am in fact registering the ActionFilter with:

GlobalConfiguration.Configuration.Filters.Add(new NhSessionManagementAttribute());

I have also decorated both my controller class itself, as well as its actions with the attribute to no avail:

public class ClientsController : ApiController {
    static readonly ClientRepository repository = new ClientRepository();

    [NhSessionManagement]
    public IEnumerable<Client> GetAllClients() {
        return repository.GetAll();
    }

    [NhSessionManagement]
    public Client GetClient(int id) {
        Client client = repository.Get(id);
        if (client == null) {
            throw new HttpResponseException(
                new HttpResponseMessage(HttpStatusCode.NotFound)
            );
        }
        return client;
    }
}

Why would this action filter not be firing any of the events within?

Answer 1

If you're working in a project contains both MVC and WebAPI assembilies, could you check what's the namespace your ActionFilterAttribute's namespace. It's fairly confusing cause there are two ActionFilterAttributes under both:

• WebAPI: System.Web.Http.Filters
• MVC: System.Web.Http.Mvc

Answer 2

The answer above definitely helped me - to save others some time... here is explicitly the difference.

Standard MVC Controllers use:

// System.Web.Mvc
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
    base.OnActionExecuting(filterContext);
}

OData HTTP Controllers use:

// System.Web.Http.Filters;
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
    base.OnActionExecuted(actionExecutedContext);
}

Answer 3

For anyone else who comes across this, ActionFilterAttribute will not fire when calling YourController.YourAction from your UnitTest.

[TestMethod]
public void RevokeSiteAdmin_SessionOver()
{
    FakeDbContext db = new FakeDbContext();

    YourController controller = new YourController(db);
    var result = controller.YourAction();

    //Some Assertions
}

In the TestMethod above, any ActionFilterAttributes on YourController.YourAction will not be called. However; if you call YourController.YourAction from a browser, your ActionFilterAttribute will be called.

This is true for at least WebApi, but I don't know if it applies to MVC.

Answer 4

Here is the complete Implementation:

public class AllowCrossSiteJsonAttribute : System.Web.Mvc.ActionFilterAttribute
{
    public override void OnActionExecuted(System.Web.Mvc.ActionExecutedContext filterContext)
    {
        if (filterContext.HttpContext != null && filterContext.HttpContext.Response != null && filterContext.HttpContext.Request != null && filterContext.HttpContext.Request.UrlReferrer != null)
        {
            var allowedCrossDomains = TypeSafeConfigurationManager.GetValueString("allowedCrossDomains", "none");
            var allowedHosts = allowedCrossDomains.Split(',');

            var requestHost =  filterContext.HttpContext.Request.UrlReferrer.GetLeftPart(UriPartial.Authority);
            if (allowedHosts.Contains(requestHost.ToLower()))
            {
                filterContext.HttpContext.Response.Headers.Add("Access-Control-Allow-Origin", requestHost);
            }
        }

        base.OnActionExecuted(filterContext);
    }
}
public class AllowCrossSiteJsonForWebApiAttribute : ActionFilterAttribute
{
    public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
    {
        if (actionExecutedContext.Response != null && actionExecutedContext.Request != null &&
            actionExecutedContext.Request.Headers.Referrer != null)
        {
            var allowedCrossDomains = TypeSafeConfigurationManager.GetValueString("allowedCrossDomains", "none");
            var allowedHosts = allowedCrossDomains.Split(',').ToList();

            var requestHost = actionExecutedContext.Request.Headers.Referrer.GetLeftPart(UriPartial.Authority);

            if (allowedHosts.Contains(requestHost.ToLower()))
            {
                actionExecutedContext.Response.Headers.Add("Access-Control-Allow-Origin", requestHost);
            }

            base.OnActionExecuted(actionExecutedContext);
        }
    }
}

Answer 5

For WebApi, you should install Microsoft.AspNet.WebApi.Core from nuget. For MVC you can use System.Web.MVC.

Answer 6

My problem was much more simple:

Check your Controller is decorated with <actionPreProcessActivitiesAttribute()> _