passing action method parameter to ActionFilterAttribute in asp.net mvc

Question

I know that I can use the filterContext to get to it. However, this is not very flexible if the action method parameter is named differently. This should work:

[HttpGet]
[NewAuthoriseAttribute(SomeId = id)]
public ActionResult Index(int id)
{
    ...

public class NewActionFilterAttribute : ActionFilterAttribute
{   
    public int SomeId { get; set; }
    ...

but it does not (it does not even compile). Any ideas?

Mme

Attributes are metadata and as such can only have constant values. – Talkington

I think I came across this whilst googleing. I guess I could pass the name of the integer down to the attribute and then look for it in the filtercontext. what do you think? – Mme

Are you planning to base some of the authorization on a value sent to the application? Doesn't this give the user a chance to effect the authorization outcome? – Talkington

No sorry - my actionfiltername was misleading. i have changed that. – Mme

Answer 1

Building on the answer from @Pankaj and comments from @csetzkorn:

You pass the name of the parameter as a string then check the filterContext

public class NewAuthoriseAttribute : ActionFilterAttribute
{
    public string IdParamName { get; set; }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (filterContext.ActionParameters.ContainsKey(IdParamName))
        {
            var id = filterContext.ActionParameters[IdParamName] as Int32?;
        }
    }
}

[NewAuthorizeAttribute(IdParamName = "fooId")]
public ActionResult Index(int fooId)
{ ... }

Yourself

What about if I want to pass the model state to this action filter? – Ambassador

the "ContainsKey" method can throw an ArgumentNullException in case you decide to omit the "IdParamName" parameter. Be sure you check that: if (IdParamName != null && filterContext.ActionParameters.ContainsKey(IdParamName)) – Applause

Answer 2

Edit

I am assuming that you are looking to make the Alias of Parameter name. This is giving you the flexibility to have multiple Alias of your paramater Name.

ActionParameterAlias.ParameterAlias Overloads

If so, you can give alias like below.

[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name")]
[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name1")]
[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name2")]
[ParameterAlias("Original_Parameter_Name", 
                 "New_Parameter_Name3")]

public ActionResult ActionMethod(Model ParameterValue) { return View(ParameterValue); }

---

Original Post

Try this one.

Attribute

public class NewAuthoriseAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (filterContext.ActionParameters.ContainsKey("id"))
        {
            var id = filterContext.ActionParameters["id"] as Int32?;
        }
    }
}

Action Method

Make sure to set the Parameter type nullable to avoid RunTime Crash.

[NewAuthoriseAttribute]
public ActionResult Index(Int32? id)
{
}

Embonpoint

as I said - that's not an option and I am aware of this. The reason why I do not want to use this approach is that id can also be called a, b, c etc. – Mme

Then add the name of the ActionParameters key to the constructor of the attribute. – Flashback

Answer 3

In the new versions, you only need to define a property inside the class and set the value above the methods.

public enum Roles
{
    Admin = 1,
    User
}

---

public class CustomAuthorizationAttribute : ActionFilterAttribute

{
    public Roles Role { get; set; }

    public override void OnActionExecuting(ActionExecutingContext context)
    {
        if (Role == Roles.Admin)
        {
            throw new UnauthorizedException(HttpStatusCode.Unauthorized, "AccessDenied", ResponseMessage.InvalidToken);
        }

        base.OnActionExecuting(context);
    }
}

---

  [CustomAuthorization(Role = Roles.Admin)]
    public IActionResult OnlyAdmin()
    {
        return Content("Hi Admin");
    }

Kaspar