webserviceauthenticationmodule.vb

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Imports System
Imports System.Web
Imports System.IO
Imports System.Xml
Imports System.Xml.XPath
Imports System.Text
Imports System.Web.Services.Protocols

Namespace Microsoft.WebServices.Security

	Public NotInheritable Class WebServiceAuthenticationModule
        Implements IHttpModule
	
		Private _eventHandler As WebServiceAuthenticationEventHandler = Nothing

        Public Event Authenticate As WebServiceAuthenticationEventHandler
			Add
				AddHandler _eventHandler, AddressOf value
			End Add
			Remove
				RemoveHandler _eventHandler, AddressOf value
			End Remove
		End Event
	
        Public Overrides Overloads Sub Dispose() Implements IHttpModule.Dispose
        End Sub

        Public Sub Overrides Overloads Init(app As HttpApplication) Implements IHttpModule.Init
            AddHandler app.AuthenticateRequest, New EventHandler(AddressOf Me.OnEnter)
        End Sub

        Private Sub OnAuthenticate(ByVal e As WebServiceAuthenticationEvent)
            If (_eventHandler Is Nothing) Then
                Return
            End If

            _eventHandler(Me, e)
            If Not (e.User Is Nothing) Then
                e.Context.User = e.Principal
            End If
        End Sub

        Public ReadOnly Property ModuleName() As String
            Get
                Return "WebServiceAuthentication"
            End Get
        End Property

        Sub OnEnter(ByVal source As Object, ByVal eventArgs As EventArgs)
            Dim app As HttpApplication = CType(source, HttpApplication)
            Dim context As HttpContext = app.Context
            Dim HttpStream As Stream = context.Request.InputStream

            ' Current position of stream
            Dim posStream As Long = HttpStream.Position

            ' If the request contains an HTTP_SOAPACTION 
            ' header we'll look at this message
            If (context.Request.ServerVariables("HTTP_SOAPACTION") Is Nothing) Then
                Return
            End If

            ' Load the body of the HTTP message
            ' into an XML document
            Dim dom As New XmlDocument()
            Dim soapUser As String
            Dim soapPassword As String

            Try
                dom.Load(HttpStream)

                ' Reset the stream position
                HttpStream.Position = posStream

                ' Bind to the Authentication header
                soapUser = dom.GetElementsByTagName("User").Item(0).InnerText
                soapPassword = dom.GetElementsByTagName("Password").Item(0).InnerText

            Catch e As Exception
                ' Reset Position of stream
                HttpStream.Position = posStream

                ' Throw a SOAP Exception
                Dim name As New XmlQualifiedName("Load")
                Dim soapException As New SoapException("Unable to read SOAP request", name, e)
                Throw soapException
            End Try

            ' Raise the custom global.asax event
            OnAuthenticate(New WebServiceAuthenticationEvent(context, soapUser, soapPassword))

            Return
        End Sub
    End Class
End Namespace