using filters with autofac in webapi2 - autofac

Question

I have a actionfilter something as below.. The filter basically adds a few attributes to the header of the response..
public class myHeaderAttribute : ActionFilterAttribute
{
public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
{
if (actionExecutedContext.Response != null)
//my code goes here
base.OnActionExecuted(actionExecutedContext);
}
}
I would normally call this in WebApiConfig.Register as config.Filters.Add(new myHeaderAttribute());
I wish to use Autofac in my project..
There is a page in autofac site (http://docs.autofac.org/en/latest/integration/webapi.html)which speaks of implementing IAutofacActionFilter.
But, I'm not very clear as to what I'm supposed to do.
I can create another class which implements IAutofacActionFilter and add the onActionExecuted method.
But do I also keep my present class or remove it along with the line in WebApiConfig.Register.
Also the page speaks of registering the Autofac filter provider as well as the class which implements IAutofacActionFilter. But no complete example exists.
Also, it speaks of using 'service location' in case we need per-request or instance-per-dependency services in our filters.
The whole thing seems a little too confusing to me. I would sincerely appreciate if someone who understands these concepts and has used Autofac in a web api2 project could guide me.
Thanks

Answer 1

Remove it. It explains exactly in the docs you reference yourself that it uses its own action filter resolver. See section "Provide filters via dependency injection".
Update
First register the filter provider:
var builder = new ContainerBuilder();
builder.RegisterWebApiFilterProvider(config);
Then register your actionfilter like so:
builder.Register(c => new myHeaderAttribute())
.AsWebApiActionFilterFor<YourController>(c => c.YourMethod(default(int)))
.InstancePerApiRequest();
So complete code:
var builder = new ContainerBuilder();
builder.RegisterWebApiFilterProvider(config);
builder.Register(c => new myHeaderAttribute())
.AsWebApiActionFilterFor<YourController>(c => c.YourMethod(default(int)))
.InstancePerApiRequest();
It's all right there in the docs. If you have any specific question then you can ask seperately. But this is becoming to be too broad.