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thousands or even millions of channel URIs. For this reason, seriously evaluate whether periodic
notifications will be sufficient for your scenario, especially for updates that aren’t user specific, because
they will be much simpler on the service side of the picture.
Requesting and Caching a Channel URI (App)
Requesting a channel URI is done through the
Windows.Networking.PushNotifications.PushNotificationChannelManager object. This manager has
only two methods: createPushNotificationChannelForApplicationAsync and
createPushNotificationChannelForSecondaryTileAsync. The first is clearly linked to the app tile as well
as toast notifications; the second is clearly for use with secondary tiles and takes a tileId argument to
identify the specific one.
The result of both async operations is a PushNotificationChannel object that will be passed to your
completed handler, as shown in Scenario 1 of the sample (start in js/scenario1.js, then go into
js/notifications.js):
var channelOperation;
// Channel for the app tile
if (isPrimaryTile) {
channelOperation = Windows.Networking.PushNotifications.PushNotificationChannelManager
.createPushNotificationChannelForApplicationAsync();
} else {
// Channel for a secondary tile
channelOperation = Windows.Networking.PushNotifications.PushNotificationChannelManager
.createPushNotificationChannelForSecondaryTileAsync(itemId);
}
channelOperation.done(function (newChannel) {
// Send channel to web service
}, /* error handler */
);
The PushNotificationChannel object (newChannel in the code above) is a simple object with just a
few members, but they are important ones:
• expirationTime A read-only property indicating when the channel expires—notifications sent
to this channel after expiration will be rejected. Apps must be sure to refresh their channels when
needed to avoid an interruption in notifications.
• uri A read-only URI to which the app’s web service sends notifications to WNS.
• close A method that explicitly invalidates the channel.
• pushnotificationreceived An event that’s fired when a notification is received on the client
device from this notification channel. This will be fired only for apps that are in the foreground.
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