Limiting Mvc 3 Action links or Functions based On Date - asp.net-mvc

Question

I have a mvc 3 vb.net razor App that I need to redirect the view to a different action if the link is not clicked on between a preset range of Month/Day/Year ranges... This is needed to limit registration for a school semester to only be able to be performed between and Open Registration Date and a End Registration Date... I am thinking I can simply put this in the controller function in the form of either a If Statement or a select case and then use redirect based on the condition of the date...... Is there some simple short code to use to perform this test... My variables for the dates are OpenDate and EndDate. I think its probably something close to
Dim OpenDate as date = mm/dd/yy
Dim CloseDate as date = mm/dd/yy
If system.datetime.now.toshortdatestring < OpenDate Then
Return RedirecttoAction ("Too Soon")
ElseIf system.datetime.now.toshortdatestring > CloseDate Then
Return RedirecttoAction ("Too Late")
Else
Return View()
End If
Does this look good or is there a easier way???

Answer 1

I would write a custom authorization attribute:
Public Class MyAuthorizeAttribute
Inherits AuthorizeAttribute
Private ReadOnly _openDate As DateTime
Private ReadOnly _closeDate As DateTime
Public Sub New(openDate As String, closeDate As String)
_openDate = DateTime.ParseExact(openDate, "dd/MM/yyyy", CultureInfo.InvariantCulture)
_closeDate = DateTime.ParseExact(closeDate, "dd/MM/yyyy", CultureInfo.InvariantCulture)
End Sub
Protected Overrides Function AuthorizeCore(httpContext As HttpContextBase) As Boolean
Dim now = DateTime.Now
If now < _openDate Then
httpContext.Items("actionToRedirectTo") = "toosoon"
Return False
End If
If now > _closeDate Then
httpContext.Items("actionToRedirectTo") = "toolate"
Return False
End If
Return True
End Function
Protected Overrides Sub HandleUnauthorizedRequest(filterContext As AuthorizationContext)
Dim values = New RouteValueDictionary(New With { _
Key .action = filterContext.HttpContext.Items("actionToRedirectTo"), _
Key .controller = "somecontroller" _
})
filterContext.Result = New RedirectToRouteResult(values)
End Sub
End Class
and then simply decorate controller actions that need this kind of logic with it:
<AuthorizeRegistration("01/11/2011", "01/12/2011")>
Function Register() As ActionResult
Return View()
End Function
This way you can reuse it on different actions that need this kind of protection.

Answer 2

You want to limit registration for a school semester by date, so the given date for registration should be valid - this is a validation concern so you should implement go for validation with an error message and not redirecting special views.
You can use the Range (System.ComponentModel.DataAnnotations) attribute on your model for your purposes. If you would need more dynamic values for date range validation you should write your own custom validation attribute.