LicenseAcquirer.OnAcquireLicense Method
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
The default implementation of this method calls into the MediaElement to acquire a license. You should override this method if you want to handle the license acquisition yourself.
Assembly: System.Windows (in System.Windows.dll)
'Declaration Protected Friend Overridable Sub OnAcquireLicense ( _ licenseChallenge As Stream, _ licenseServerUri As Uri _ )
Parameters
- licenseChallenge
- Type: System.IO.Stream
The PlayReady license acquisition challenge, which is to be sent to a PlayReady Server instance.
- licenseServerUri
- Type: System.Uri
The URI of the License Server. If the LicenseServerUriOverride property is set, then this parameter will contain the value of the LicenseServerUriOverride. If not set, then this parameter will return the value of the License Server URI found inside the WRMHeader header. In the case of WMDRM packaged content, the License Server URI will always be reset to Nothing.
If the LicenseAcquirer is created on demand (from the media element), the OnAcquireLicense method is called when the Media pipeline is building a topology and is raised before MediaOpened is raised for a particular Source or entry of a Source. If the LicenseAcquirer is being used in license pre-acquisition mode (prior to attempting playback), the OnAcquireLicense method is called, but no media element events are raised.
You should override the OnAcquireLicense method if you want to handle the license acquisition yourself. When overridden, this method is called by using the PlayReady license acquisition challenge as the argument. Within this method, you should set up your WebRequest and WebResponse callback and return.
If you override this method and call the base class implementation, processing will be performed automatically. (In those cases, there can be no custom protocol for the response. The response has to be the PlayReady license server response.) If you do not call the base method, you must call the SetLicenseResponse method. Otherwise, the license acquisition processing will be stalled. If the LicenseAcquirer object is attached to a MediaElement then the MediaElement will remain in the AcquiringLicense state.
The LicenseAcquirer class is used by the MediaElement to handle acquiring licenses for DRM encrypted content from a PlayReady License Server. You can create a derived class from the LicenseAcquirer class and add custom logic like adding your own custom authentication scheme to the license request.
The following example shows how to override the LicenseAcquirer class (named "ManualLicenseAcquirer") and have a MediaElement use it to acquire the license.
<StackPanel x:Name="LayoutRoot" Background="Gray" Orientation="Vertical"> <MediaElement x:Name="myME" Height="100"/> </StackPanel>
Public Class Page Inherits UserControl Public Sub New() MyBase.New InitializeComponent AddHandler Loaded, AddressOf Me.Page_Loaded End Sub Private Sub Page_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs) ' Test a full fledged manual acquirer ' Set the LicenseAcquirer of the MediaElement to the custom License Acquirer ' defined in this sample. myME.LicenseAcquirer = New ManualLicenseAcquirer(myME.Name) ' Set the License URI to proper License Server address. myME.LicenseAcquirer.LicenseServerUriOverride = New Uri("http://contoso.com/myLicenseServer.asmx", UriKind.Absolute) AddHandler myME.MediaFailed, AddressOf Me.myME_MediaFailed ' Set the source of the MediaElement to the URL of the media encrypted with WMDRM. myME.Source = New Uri("http:, contoso.com/wmdrm_url.wmv", UriKind.Absolute);) End Sub Private Sub myME_MediaFailed(ByVal sender As Object, ByVal e As ExceptionRoutedEventArgs) Dim errorMessage As String = "" If e.ErrorException.ToString.Contains(" 6001 ") Then errorMessage = "The individualization component software failed to" & _ " download to the user's computer. This error would" & _ " come up when the MediaElement is in the Individualizing" & _ " MediaElementState. One possible reason for this error is" & _ " that Windows Phone cannot connect the Microsoft" & _ " Individualization Server." ElseIf e.ErrorException.ToString.Contains(" 6004 ") Then errorMessage = "The installation of Windows Phone on the device is" & _ " out of date and needs to be updated." Else errorMessage = "MediaFailed: " & _ + e.ErrorException.Message + "." End If System.Windows.Browser.HtmlPage.Window.Alert(errorMessage) End Sub ' makes license request explicitly Public Class ManualLicenseAcquirer Inherits LicenseAcquirer Private challengeString As String Private _mediaElementName As String Public Sub New(ByVal mediaElementName As String) MyBase.New _mediaElementName = mediaElementName End Sub ' The default implementation of OnAcquireLicense calls into the MediaElement to acquire a ' license. It is called when the Media pipeline is building a topology and will be raised ' before MediaOpened is raised. Protected Overrides Sub OnAcquireLicense(ByVal licenseChallenge As System.IO.Stream, ByVal licenseServerUri As Uri) Dim sr As StreamReader = New StreamReader(licenseChallenge) challengeString = sr.ReadToEnd ' Need to resolve the URI for the License Server -- make sure it is correct ' and store that correct URI as resolvedLicenseServerUri. Dim resolvedLicenseServerUri As Uri If (LicenseServerUriOverride Is Nothing) Then resolvedLicenseServerUri = licenseServerUri Else resolvedLicenseServerUri = LicenseServerUriOverride End If ' Make a HttpWebRequest to the License Server. Dim request As HttpWebRequest = CType(WebRequest.Create(resolvedLicenseServerUri),HttpWebRequest) request.Method = "POST" ' Set ContentType through property request.ContentType = "application/xml" ' ADD REQUIRED HEADERS. ' The headers below are necessary so that error handling and redirects are handled ' properly by Windows Phone. request.Headers("msprdrm_server_redirect_compat") = "false" request.Headers("msprdrm_server_exception_compat") = "false" ' Initiate getting request stream Dim asyncResult As IAsyncResult = request.BeginGetRequestStream(New AsyncCallback(RequestStreamCallback), request) End Sub ' This method is called when the asynchronous operation completes. Private Sub RequestStreamCallback(ByVal ar As IAsyncResult) Dim request As HttpWebRequest = CType(ar.AsyncState,HttpWebRequest) ' populate request stream request.ContentType = "text/xml" Dim requestStream As Stream = request.EndGetRequestStream(ar) Dim streamWriter As StreamWriter = New StreamWriter(requestStream, System.Text.Encoding.UTF8) streamWriter.Write(challengeString) streamWriter.Close ' Make async call for response request.BeginGetResponse(New AsyncCallback(ResponseCallback), request) End Sub Private Sub ResponseCallback(ByVal ar As IAsyncResult) Dim request As HttpWebRequest = CType(ar.AsyncState,HttpWebRequest) Dim response As WebResponse = request.EndGetResponse(ar) SetLicenseResponse(response.GetResponseStream) End Sub End Class End Class