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The NetStream class provides a one-way streaming connection between
Flash Player or an AIR application, and either Flash Media Server
or the local file system. (The NetStream class also supports progressive
download.) A NetStream object is a channel within a NetConnection
object. The NetStream class dispatches four DRM-related events:
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Event
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Description
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drmAuthenticate
(AIR only)
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Defined in the DRMAuthenticateEvent class.
This event is dispatched when a NetStream object tries to play protected
content that requires a user credential for authentication before
playback.
The properties of this event include header, usernamePrompt,
passwordPrompt, and urlPrompt properties that can be used in obtaining
and setting the user’s credentials. This event occurs repeatedly
until the NetStream object receives valid user credentials.
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drmError
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Defined in the DRMErrorEvent class and dispatched
when a NetStream object tries to play protected content and encounters
a DRM-related error. For example, DRM error event object is dispatched
when the user authorization fails. This error could occur because
the user has not purchased the rights to view the content. It could also
occur because the content provider does not support the viewing
application.
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drmStatus
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Defined in the DRMStatusEvent class. This
event is dispatched when the protected content begins playing (when
the user is authenticated and authorized to play the content). The
DRMStatusEvent object contains information related to the voucher.
Voucher information includes whether the content can be made available offline
or when the voucher expires and the content can no longer be viewed.
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status
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Defined in events.StatusEvent and only dispatched
when the application attempts to play protected content, by invoking
the NetStream.play() method. The value of the status code property
is "DRM.encryptedFLV".
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The
NetStream class includes the following DRM-specific methods, for
use in AIR only:
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Method
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Description
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resetDRMVouchers()
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Deletes all the locally cached digital rights
management (DRM) voucher data. The application must download the
vouchers again for the user to be able to access the encrypted content.
For
example, the following code removes all vouchers from the cache:
NetStream.resetDRMVouchers();
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setDRMAuthenticationCredentials()
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Passes a set of authentication credentials,
namely user name, password, and authentication type, to the NetStream
object for authentication. Valid authentication types are
"drm"
and
"proxy"
. With
"drm"
authentication
type, the credentials provided are authenticated against Adobe Access.
With
"proxy"
authentication type, the credentials
authenticate against the proxy server and must match the credentials
required by the proxy server. For example, an enterprise can require
the application to authenticate against a proxy server before the
user can access the Internet. The proxy option allows this type
of authentication. Unless anonymous authentication is used, after
the proxy authentication, the user must still authenticate against
Adobe Access to obtain the voucher and play the content. You can
use
setDRMAuthenticationCredentials()
a second time,
with “
drm
" option, to authenticate against Adobe
Access.
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preloadEmbeddedMetadata()
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Parses a local media file for embedded metadata.
When DRM-related metadata is found, AIR calls the
onDRMContentData()
callback
function.
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In addition, in AIR, a NetStream object calls the
onDRMContentData()
and
onPlayStatus()
callback
functions as a result of a call to the
preloadEmbeddedMetaData()
method.
The
onDRMContentData()
function is called when
DRM metadata is encountered in a media file. The
onPlayStatus()
function
is called when the file has been parsed. The
onDRMContentData()
and
onPlayStatus()
functions
must be defined on the
client
object assigned to
the NetStream instance. If you use the same NetStream object to
preload vouchers and play content, wait for the
onPlayStatus()
call
generated by
preloadEmbeddedMetaData()
before starting
playback.
In the following code for AIR, user name (“administrator”), password
(“password”) and the “drm” authentication type are set for authenticating
the user. The setDRMAuthenticationCredentials() method must provide
credentials that match credentials known and accepted by the content
provider. These credentials are the same user credentials that permit
the user to view the content. The code for playing the video and
making sure that a successful connection to the video stream has
been made is not included here.
var connection:NetConnection = new NetConnection();
connection.connect(null);
var videoStream:NetStream = new NetStream(connection);
videoStream.addEventListener(DRMAuthenticateEvent.DRM_AUTHENTICATE,
drmAuthenticateEventHandler)
private function drmAuthenticateEventHandler(event:DRMAuthenticateEvent):void
{
videoStream.setDRMAuthenticationCredentials("administrator", "password", "drm");
}
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