As mentioned in my previous article How to build huge dynamically loading cross platform Silverlight Business Applications, I’m experimenting with the idea of a hybrid web application that has some parts implement as webforms, others as Silverlight.
A problem I encountered was that RIAService calls did not necessarily access to the same information as my webforms did. An example is “SessionState”. In the case of my company’s framework, the authentication system must be invoked prior to anything else within my domain services. In addition the authentication system needs access to SessionState.
To do this I thought I could inherit from DataServiceFactory and add what I needed. Unfortunately the class is marked as not inheritable. The way around this is to encapsulate the class.
In the code sample below you can see an implementation of MyDataServiceFactory that encapsulates DataServiceFactory and returns an encapsulated HttpHandler that flags to ASP.Net that sessionstate is needed.
Imports System.Web
Imports System.Web.SessionState
Public Class MyDataServiceFactory
Implements IHttpHandlerFactory
Private moHandlerFactory As IHttpHandlerFactory
Public Sub New()
moHandlerFactory = New System.Web.Ria.DataServiceFactory
End Sub
Public Function GetHandler(ByVal context As System.Web.HttpContext, ByVal requestType As String, ByVal url As String, ByVal pathTranslated As String) As System.Web.IHttpHandler Implements System.Web.IHttpHandlerFactory.GetHandler
Return New MyDataServicesHandler(moHandlerFactory.GetHandler(context, requestType, url, pathTranslated))
End Function
Public Sub ReleaseHandler(ByVal handler As System.Web.IHttpHandler) Implements System.Web.IHttpHandlerFactory.ReleaseHandler
moHandlerFactory.ReleaseHandler(DirectCast(handler, MyDataServicesHandler).InnerHandler)
End Sub
End Class
Public Class MyDataServicesHandler
Implements IHttpHandler
Implements IRequiresSessionState ' Let ASP.Net know that you need to use the session object
Public InnerHandler As IHttpHandler
Public Sub New(ByVal handlerToWrap As IHttpHandler)
InnerHandler = handlerToWrap
End Sub
Public ReadOnly Property IsReusable() As Boolean Implements System.Web.IHttpHandler.IsReusable
Get
Return InnerHandler.IsReusable
End Get
End Property
Public Sub ProcessRequest(ByVal context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest
' You can access context.Session here if you want to...
InnerHandler.ProcessRequest(context)
End Sub
End Class
Of course to use this, you need to modify the web.config and change the two references to DataServicesFactory to point to your new class instead, which should be hosted in it’s own class library.
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