LicenseAcquirer.OnAcquireLicense Method
Microsoft Silverlight will reach end of support after October 2021. Learn more.
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.
Namespace: System.Windows.Media
Assembly: System.Windows (in System.Windows.dll)
Syntax
'Declaration
Protected Friend Overridable Sub OnAcquireLicense ( _
licenseChallenge As Stream, _
licenseServerUri As Uri _
)
protected internal virtual void OnAcquireLicense(
Stream licenseChallenge,
Uri licenseServerUri
)
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 nulla null reference (Nothing in Visual Basic).
Remarks
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.
Examples
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 partial class Page : UserControl
{
public Page()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(Page_Loaded);
}
void Page_Loaded(object sender, RoutedEventArgs e)
{
// 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("https://contoso.com/myLicenseServer.asmx", UriKind.Absolute);
myME.MediaFailed += new EventHandler<ExceptionRoutedEventArgs>(myME_MediaFailed);
// Set the source of the MediaElement to the URL of the media encrypted with WMDRM.
myME.Source = new Uri("https://contoso.com/wmdrm_url.wmv", UriKind.Absolute);
}
void myME_MediaFailed(object sender, ExceptionRoutedEventArgs e)
{
string errorMessage = "";
if (e.ErrorException.ToString().Contains(" 6001 "))
{
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 the Silverlight client cannot connect the Microsoft" +
" Individualization Server.";
}
else if (e.ErrorException.ToString().Contains(" 6004 "))
{
errorMessage = " The installation of Silverlight on the client is" +
" out of date and needs to be updated.";
}
else
{
errorMessage = "MediaFailed: " + e.ErrorException.Message + ".";
}
System.Windows.Browser.HtmlPage.Window.Alert(errorMessage);
}
// makes license request explicitly
public class ManualLicenseAcquirer : LicenseAcquirer
{
private string challengeString;
string _mediaElementName;
public ManualLicenseAcquirer(string mediaElementName)
{
_mediaElementName = mediaElementName;
}
// 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 override void OnAcquireLicense(System.IO.Stream licenseChallenge, Uri licenseServerUri)
{
StreamReader sr = 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.
Uri resolvedLicenseServerUri;
if (LicenseServerUriOverride == null)
resolvedLicenseServerUri = licenseServerUri;
else
resolvedLicenseServerUri = LicenseServerUriOverride;
// Make a HttpWebRequest to the License Server.
HttpWebRequest request = WebRequest.Create(resolvedLicenseServerUri) as 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 via the Silverlight client.
request.Headers["msprdrm_server_redirect_compat"] = "false";
request.Headers["msprdrm_server_exception_compat"] = "false";
// Initiate getting request stream
IAsyncResult asyncResult = request.BeginGetRequestStream(new AsyncCallback(RequestStreamCallback), request);
}
// This method is called when the asynchronous operation completes.
void RequestStreamCallback(IAsyncResult ar)
{
HttpWebRequest request = ar.AsyncState as HttpWebRequest;
// populate request stream
request.ContentType = "text/xml";
Stream requestStream = request.EndGetRequestStream(ar);
StreamWriter streamWriter = new StreamWriter(requestStream, System.Text.Encoding.UTF8);
streamWriter.Write(challengeString);
streamWriter.Close();
// Make async call for response
request.BeginGetResponse(new AsyncCallback(ResponseCallback), request);
}
private void ResponseCallback(IAsyncResult ar)
{
HttpWebRequest request = ar.AsyncState as HttpWebRequest;
WebResponse response = request.EndGetResponse(ar);
SetLicenseResponse(response.GetResponseStream());
}
}
}
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("https://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 the Silverlight client cannot connect the Microsoft" & _
" Individualization Server."
ElseIf e.ErrorException.ToString.Contains(" 6004 ") Then
errorMessage = "The installation of Silverlight on the client 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 via the Silverlight client.
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
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
See Also