How can I redirect from my controller using AuthorizeAttributes?

Question

I have made an AuthorizeAttributeBase to extend AuthorizeAttribute. It looks like this:

public abstract class MyAuthorizeAttribute : AuthorizeAttribute
{
//Holds the roles allowed to perform the action.
public IEnumerable<string> roles { get; set; }

/// <summary>
/// Authorizes if the current user may perform the action
/// </summary>
/// <param name="httpContext">Unused - included for override purposes.</param>
/// <returns>true if authorized.</returns>
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
    //Return true if user is in the action allowed roles.
    if (IsUserInRole)
    {
        return true;
    }
    else
    {
        HttpContext.Current.Response.StatusCode = 401;
        return false;
    }
}

/// <summary>
/// Checks if the user is member of a role that is allowed by the authorization
/// </summary>
public bool IsUserInRole
{
    get
    {
        if (roles != null)
        {
            //Check if any of the roles in the session is in the list of roles of the authorization
            return (MySessionGetter.GetSession().Roles.Intersect<string>(roles).Any());
        }
        //If none of the roles match return false.
        return false;
    }
}

/// <summary>
/// Sets the allowed roles of the authorization
/// </summary>
/// <param name="userRoles">Allowed roles</param>
public void AlowedRoles(IEnumerable<string> userRoles)
{
    roles = userRoles;
}

I keep the allowed rolenames like this:

/// <summary>
/// Holds the role names.
/// </summary>
public static class UserRoles
{
    public static string Administrators = "Administrators";
    public static string Teachers= "Teachers";
}

And use my base like this:

/// <summary>
/// Authorization for the access to the SomeAction 
/// </summary>
public class AuthorizeAccessToSomeActionAttribute : MyAuthorizeAttribute
{
    public AuthorizeAccessToSomeActionAttribute()
    {
        AlowedRoles(new List<string> {  UserRoles.Adminstrators, 
                                            UserRoles.Teachers });
    }
}    

And last but not least the controller:

    /// <summary>
    /// The main Index view of application
    /// </summary>
    /// <returns>Application Index views</returns>
    [AuthorizeAccessToSomeAction]
    public ActionResult Index()
    {
            return View("Index");
    }

Now what I want to do is make the index switch return value on base of the AuthorizeAttributes. Lets say Teachers to the TeachersIndex() and Administrators to the AdministratorsIndex().

I tried adding this to the base:

//Checks if the current user is authorized. 
public bool IsAuthorized()
{
    return AuthorizeCore(new HttpContextWrapper());
}

But I end up having to create new AutorizeAttributes every time. Making it static seemed to give me even more problems.

Is there a correct way of going about this?

---

Solved it. :) The OnAuthorization override got me a new lead. Found this question.

I put the redirects in a Dictionary<string, RedirectToRouteResult> because I like the idea of keeping all role strings in one place instead of filling up my controllers with magic strings.

public static Dictionary<string, RedirectToRouteResult>     HomeRedirect
    {
        get
        {
            return new Dictionary<string, RedirectToRouteResult> {
                {"Administrators", new RedirectToRouteResult(
                    new RouteValueDictionary { { "action", "AdministratorIndex" }, { "controller", "MyController" }})},
                {"Teacher", new RedirectToRouteResult(
                    new RouteValueDictionary { { "action", "TeacherIndex" }, { "controller", "MyController" }})}
};

And the override HandleUnauthorizedRequest looks like this now:

        protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext) {
        filterContext.Result = UserRoles.HomeRedirect
            .SingleOrDefault(m => m.Key == MySessionGetter.GetSession().Roles.First()).Value;
    }

Answer 1

Take a look at RedirectToRouteResult and RedirectResult. Here would be a good start:

// Redirects users of given role to given action
public class AuthorizeAccessToSomeActionAttribute : MyAuthorizeAttribute
{
    public string Role { get; set; }
    public string RedirectToAction { get; set; }

    public AuthorizeAccessToSomeActionAttribute(string role, string action)
    {
        Role = role;
        RedirectToAction = action;
    }
    public override void OnAuthorization(AuthorizationContext filterContext)
    {
       // Test if current user is in the role
       if (filterContext.HttpContext.User.IsInRole(Role))
       {
            // Get current routevalues
            var rvals = filterContext.RouteData.Values;
            // Change action
            rvals["action"] = RedirectToAction;
            filterContext.Result = new RedirectToRouteResult("Default",rvals);
       }
    }
} 

Usage:

    // Redirect role to given action
    [AuthorizeAccessToSomeActionAttribute("Teacher", "TeacherIndex" )]
    [AuthorizeAccessToSomeActionAttribute("Admin", "AdminIndex" )]
    public ActionResult Index()
    ...
    public ActionResult TeacherIndex()
    ...
    public ActionResult AdminIndex()