IWMSAuthenticationContext.Authenticate (Visual Basic .NET)
The server calls the Authenticate method to verify client credentials.
IWMSAuthenticationContext.Authenticate( ResponseBlob As Object,
pUserCtx As IWMSContext,
pPresentationCtx As IWMSContext,
pCommandContext As IWMSCommandContext,
pCallback As IWMSAuthenticationCallback,
Context As Object
)
Arguments
Object containing client authentication data passed from the server. The exact nature of the data is specific to the authentication protocol being used. |
|
IWMSContextIWMSContext Object (Visual Basic .NET) containing the user context. The plug-in fills the context. |
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IWMSContext object containing the presentation context. The plug-in fills the context. |
|
IWMSCommandContextIWMSCommandContext Object (Visual Basic .NET) containing the request context. The plug-in fills the context. |
|
IWMSAuthenticationCallbackIWMSAuthenticationCallback Object (Visual Basic .NET). The plug-in calls the IWMSAuthenticationCallback.OnAuthenticateComplete method to send the results of the authentication process to the server. |
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Object containing a value defined by the server to identify which call to Authenticate the plug-in is responding to when it calls IWMSAuthenticationCallback.OnAuthenticateComplete. You must pass this value back unaltered. |
Return Value
This method does not return a value. To report an error, the plug-in can throw a COMException object to the server. If the plug-in uses the IWMSEventLogIWMSEventLog Object (Visual Basic .NET) to log error information, it is recommended that it throw NS_E_PLUGIN_ERROR_REPORTED (0xC00D157D). Typically, the server attempts to make plug-in error information available to the server object model, the Windows Event Viewer, and the troubleshooting list in the details pane of the Windows Media Services MMC. However, if the plug-in uses the IWMSEventLog object to send custom error information to the Windows Event Viewer, throwing NS_E_PLUGIN_ERROR_REPORTED stops the server from also logging to the event viewer. For more information about plug-in error information, see Identifying Plug-in Errors.
Remarks
The server calls the Authenticate method. The plug-in must call the IWMSAuthenticationCallback.OnAuthenticateComplete method.
Example
' This sample implementation of the Authenticate method
' uses a digest authentication scheme.
Public Sub Authenticate(ByVal ResponseBlob As Object, _
ByVal pUserCtx As IWMSContext, _
ByVal pPresentationCtx As IWMSContext, _
ByVal pCommandContext As IWMSCommandContext, _
ByVal pCallback As IWMSAuthenticationCallback, _
ByVal Context As Object) _
Implements IWMSAuthenticationContext.Authenticate
Dim AUTH_QOP As String = "auth"
Dim AUTH_REALM As String = "RealmName"
Dim Enc As Text.Encoding = Text.Encoding.Unicode
Dim strNonce As String = GenerateNonce()
Dim Response As Byte()
Dim Challenge As Byte()
Try
Response = ResponseBlob
If Response.Length = 0 Then
' The client requested authentication; prepare the
' challenge response to send to the client.
Challenge = Enc.GetBytes("realm=" & Chr(34) & _
AUTH_REALM & Chr(34) & _
",qop=" & Chr(34) & _
AUTH_QOP & Chr(34) & _
",nonce=" & Chr(34) & _
strNonce & Chr(34) & _
",charset=utf-8,algorithm=MD5-sess")
m_Result =
WMS_AUTHENTICATION_RESULT.WMS_AUTHENTICATION_CONTINUE
Else
' The client has responded to the authentication
' challenge; verify the client credentials.
Dim CommandReq As IWMSContext
Dim strResponse As String
Dim strUserName As String
Dim strRealm As String
Dim strURI As String
Dim strCNonce As String
Dim strNonceCount As String
Dim strChalResponse As String
Dim strCommandName As String
Dim strUserHash As String
Dim strA1Hash As String
Dim strA2Hash As String
Dim strDigestHash As String
Dim bOK As Boolean
strResponse = Enc.GetString(Response)
SplitResponse(strResponse, strUserName, strRealm, strURI, _
strCNonce, strNonceCount, strChalResponse)
pCommandContext.GetCommandRequest(CommandReq)
CommandReq.GetStringValue("@ WMS_COMMAND_NAME", 153, _
strCommandName, _
WMS_CONTEXT_OPTIONS.WMS_CONTEXT_GET_PROPERTY_STRING_BY_REFERENCE)
' Retrieve the user hash from the user database.
strUserHash = GetUserHash(strUserName)
strA1Hash = GetHash(strUserHash & ":" & strNonce & _
":" & strCNonce)
strA2Hash = GetHash(strCommandName & ":" & strURI)
strDigestHash = GetHash(strA1Hash & ":" & strNonce & ":" & _
strNonceCount & ":" & strCNonce & _
":" & AUTH_QOP & ":" & strA2Hash)
' If the computed digest hash is equal to the
' client response, the user can be authenticated.
If strDigestHash = strChalResponse Then
bOK = LogonUser("media_client", "", "password", _
LOGON32_LOGON_NETWORK, _
LOGON32_PROVIDER_DEFAULT, _
m_hToken)
If bOK Then
m_Result = _
WMS_AUTHENTICATION_RESULT.WMS_AUTHENTICATION_SUCCESS
Else
m_Result = _
WMS_AUTHENTICATION_RESULT.WMS_AUTHENTICATION_ERROR
End If
Else
m_Result = _
WMS_AUTHENTICATION_RESULT.WMS_AUTHENTICATION_DENIED
End If
Challenge = Enc.GetBytes("")
End If
Catch e As Exception
m_Result = WMS_AUTHENTICATION_RESULT.WMS_AUTHENTICATION_ERROR
Finally
' Report the results of the authentication
' challenge to the server.
pCallback.OnAuthenticateComplete(m_Result, Challenge, Context)
End Try
End Sub
Private Function GetHash(ByVal strIn As String) As String
Dim Enc As Text.Encoding = Text.Encoding.ASCII
Dim md5 As MD5 = New MD5CryptoServiceProvider()
Dim bytInPtr As Byte() = Enc.GetBytes(strIn)
Dim bytMD5Ptr As Byte() = md5.ComputeHash(bytInPtr)
Dim strHash As String = BitConverter.ToString(bytMD5Ptr)
strHash = strHash.Replace("-", "").ToLower()
Return strHash
End Function
Requirements
Reference: Add a reference to Microsoft.WindowsMediaServices.
Namespace: Microsoft.WindowsMediaServices.Interop.
Assembly: Microsoft.WindowsMediaServices.dll.
Library: WMSServerTypeLib.dll.
Platform: Windows Server 2003, Enterprise Edition; Windows Server 2003, Datacenter Edition; Windows Server 2008.