asp-classic-unified-framework/core/lib.ControllerFactory.asp

<%
'=======================================================================================================================
' Controller Factory
'
' Centralizes controller instantiation by name so the MVC dispatcher (a WSC,
' with its own isolated script engine) never has to Execute/Eval a string
' built from a route-supplied controller name to resolve a class. Each
' controller factory function (e.g. HomeController(), which already exists as
' each controller's own singleton accessor) is registered once, by reference,
' via GetRef - not by re-deriving it from a string at dispatch time.
'=======================================================================================================================

Class ControllerFactory_Class
    Private m_factories

    Private Sub Class_Initialize()
        Set m_factories = Server.CreateObject("Scripting.Dictionary")
        m_factories.CompareMode = 1 ' vbTextCompare, case-insensitive
    End Sub

    Private Sub Class_Terminate()
        Set m_factories = Nothing
    End Sub

    '---------------------------------------------------------------------------------------------------------------------
    ' Register a controller's factory function (its own singleton accessor,
    ' e.g. GetRef("HomeController")) under its route name.
    '---------------------------------------------------------------------------------------------------------------------
    Public Sub Register(controllerName, factoryFunctionRef)
        Dim key : key = LCase(Trim(controllerName))
        If Not m_factories.Exists(key) Then
            m_factories.Add key, factoryFunctionRef
        End If
    End Sub

    '---------------------------------------------------------------------------------------------------------------------
    ' Create(controllerName) -> the controller singleton instance
    '---------------------------------------------------------------------------------------------------------------------
    Public Function Create(controllerName)
        Dim key, fn
        key = LCase(Trim(controllerName))

        If Not m_factories.Exists(key) Then
            Err.Raise vbObjectError + 1100, "ControllerFactory.Create", "No factory registered for controller: " & controllerName
        End If

        Set fn = m_factories(key)
        Set Create = fn()
    End Function

    '---------------------------------------------------------------------------------------------------------------------
    Public Function IsRegistered(controllerName)
        IsRegistered = m_factories.Exists(LCase(Trim(controllerName)))
    End Function
End Class

' Singleton instance
Dim ControllerFactory_Class__Singleton
Function ControllerFactory()
    If IsEmpty(ControllerFactory_Class__Singleton) Then
        Set ControllerFactory_Class__Singleton = New ControllerFactory_Class
    End If
    Set ControllerFactory = ControllerFactory_Class__Singleton
End Function
%>