R – IAuthorizationFilter + Ninject2

asp.net-mvcauthorizationcustom-action-filterdependency-injectionninject

I'm currently using Ninject2 to bind the various services and repositories in my MVC app. That part seems to be working just fine. Now I'd like to also bind my own class to IAuthorizationFilter and all actions that have the attribute set.

I've created a class that inherits from AuthorizationFilter and Implements IAuthorizationFilter.

I've also add this to my binding module:

Bind(Of IAuthorizationFilter).To(Of MyAuthFilter)

The last time I checked, the Ninject Mvc bits had support for also binding the 4 types of action filters.

Has anyone else done this? Whenever I run the site, the url that invokes the action marked Authorize just redirect to the login page, and never hits the breakpoint in my filter class.

If I were using a custom attribute, it would work, but changing all of the Authorize attributes defeats the purpose of using Ninject every time I want to swap one out of course.

Best Answer

It's not enough to register MVC filters with Ninject; you also have to tell MVC when to execute them. That's why you still need the custom attribute. The injection support in Ninject.Web.Mvc is to allow dependencies to be injected into filters.

Related Solutions

Asp.net-mvc – Custom Authorization MVC 3 and Ninject IoC

Attributes do not support constructor injection as they are created by the .NET Framework and are not under control of Ninject. If you really want to use a FilterAttribute (which I do not recommend) you'll have to use property injection.

Instead continue what you just began. You need a filter implementing IAuthorizationFilter (not derived from FilterAttribute, just remove it from your code above) and additionally an ordinary attribute to mark the controllers/actions.

Then change the binding:

this.BindFilter<MyAuthorizeFilter>(FilterScope.Controller, 0).WhenControllerHas<MyAuthorizeAttribute>();

See: https://github.com/ninject/ninject.web.mvc/wiki/MVC3

The problem with you current implementation is that it is found once as filter attribute and once added as normal filter. One for these instances will have the repo injected an the the repo is null for the other one.

NOTE: you can derive from an existing FilterAttribute if this simplifies your implementation. But do not use it as a attribute in this case but use it as an ordinary filter.

Ninject Binding Attribute to Filter with Constructor Arguments

I have figured it out (thanks to Remo's directions and documentation).

Use the appropriate .WithConstructorArgument extension whether you are binding to a Controller or Action filter. For example binding my action filter looks like this:

kernel.BindFilter<AuthorizationFilter>(FilterScope.Action, 0)
      .WhenActionMethodHas<RequireRolesAttribute>()
      .WithConstructorArgumentFromActionAttribute<RequireRolesAttribute>("requiredRoles", o => o.RequiredRoles);

Once I understood the Func<> signature, it all became clear. The best way I found to handle this was to

make the extension type-specific for my attribute

.WithConstructorArgumentFromActionAttribute<TAttribute>()

fetch the value from the callback object (your attribute) via lambda:
```
("argumentName", o => o.PropertyName)
```

Best Answer

Related Solutions

Asp.net-mvc – Custom Authorization MVC 3 and Ninject IoC

Ninject Binding Attribute to Filter with Constructor Arguments

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