Custom Authorize Attribute

I'm building my own membership system and I want nothing to do with the MS Membership provider. I've looked around the internet and here on StackOverflow but all I could found was membership providers built on top of the MS Membership provider.

Anyway, I've got almost everything hooked up now, but I'd like to use a custom Authorize attribute which utilized my membership infrastructure. I checked out this thread here on the site and I'm trying to do something similar, but I'm not sure that's quiet what I need. So far these are the classes I've got:

SessionManager:

public static class SessionManager : ISessionManager
{
    public static void RegisterSession(string key, object obj)
    {
        System.Web.HttpContext.Current.Session[key] = obj;
    }

    public static void FreeSession(string key)
    {
        System.Web.HttpContext.Current.Session[key] = null;
    }


    public static bool CheckSession(string key)
    {
        if (System.Web.HttpContext.Current.Session[key] != null)
            return true;
        else
            return false;
    }


    public static object ReturnSessionObject(string key)
    {
        if (CheckSession(key))
            return System.Web.HttpContext.Current.Session[key];
        else
            return null;
    }
}

SharweAuthorizeAttribute: (I am not really sure if that's actually what I should be doing)

public class SharweAuthorizeAttribute : AuthorizeAttribute
{
    protected override bool AuthorizeCore(HttpContextBase httpContext)
    {
        if (SessionManager.CheckSession(SessionKeys.User) == true)
            return true;
        else 
            return false;
    }
}

Now here's what I need:

Is my SharweAuthorizeAttribute class correct in the first place?
I need to be able to redirect unauthenticated users to the login page
I need to authorize users based on their roles (using my own role provider) so I would do something like:
```
[SharweAuthorize(Roles="MyRole")]
```

That's it I guess... Any suggestions are more than welcome :)

UPDATE: Ok I just read that page again and found the solution to question number two:

protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
{
    if (SessionManager.CheckSession(SessionKeys.User) == false)
    {
        filterContext.Result = new RedirectToRouteResult(
                        new RouteValueDictionary 
                        {
                            { "action", "ActionName" },
                            { "controller", "ControllerName" }
                        });
    }
    else
        base.HandleUnauthorizedRequest(filterContext);
}

Let me know if I got it right please...

Yes, you got it right (IMO it's safer and simpler to implement a custom membership provider, but it's your choice)

Yes, it's correct
You do it right
You inherit the roles property from the AuthorizeAttribute base class and you check in your implementation if the user is in the role.

Edit: a little more on the roles thing

if you have

[SharweAuthorize(Roles="MyRole")]

then you can check the Roles property in the AuthorizeCore method

protected override bool AuthorizeCore(HttpContextBase httpContext)
{
    if (SessionManager.CheckSession(SessionKeys.User) == true) {
        if (SessionManager.CheckUserIsInRole( Roles )) // where Roles == "MyRole"
           return true;
    }
    return false;
}