public async Task GetPushToken()
{
try
{
const string appServerKey = "BGg3UxXo3J_rH6VrJB2er_F8o7m2ZTGb2jiNm3tmlK4ORxsskX1HIVys5TA8lGkCYC-ur8GwrZMy-v0LZOwazvk";
//IBuffer appServerKeyBuffer = urlB64ToUint8Array(appServerKey).AsBuffer();
IBuffer appServerKeyBuffer = new byte[] { 4, 104, 55, 83, 21, 232, 220, 159, 235, 31, 165, 107, 36, 29, 158, 175, 241, 124, 163, 185, 182, 101, 49, 155, 218, 56, 141, 155, 123, 102, 148, 174, 14, 71, 27, 44, 145, 125, 71, 33, 92, 172, 229, 48, 60, 148, 105, 2, 96, 47, 174, 175, 193, 176, 173, 147, 50, 250, 253, 11, 100, 236, 26, 206, 249 }.AsBuffer();
var channel = await PushNotificationChannelManager.GetDefault().CreateRawPushNotificationChannelWithAlternateKeyForApplicationAsync(appServerKeyBuffer, "mainChannel2");
//var channel = await PushNotificationChannelManager.CreatePushNotificationChannelForApplicationAsync();
//channel.PushNotificationReceived += Channel_PushNotificationReceived; // Foreground event doesn't work
TextBoxWebEndpointUrl.Text = channel.Uri;
}
catch (Exception ex)
{
await new MessageDialog(ex.ToString()).ShowAsync();
}
}
private static async Task <PushSubscription> SubscribeHelper(string applicationServerKey, string channelId)
{
IBuffer appServerKeyBuffer = UrlB64ToUint8Array(applicationServerKey).AsBuffer();
// No matter what, we always get the channel (we don't do any caching and expiration logic, WNS caches the channel for 24 hours)
var channel = await PushNotificationChannelManager.GetDefault().CreateRawPushNotificationChannelWithAlternateKeyForApplicationAsync(appServerKeyBuffer, channelId);
var storage = await PushSubscriptionStorage.GetAsync();
var existingSubscriptionInfo = storage.GetSubscriptions(channelId).FirstOrDefault(i => i.ChannelUri == channel.Uri);
if (existingSubscriptionInfo != null)
{
// If the app server key has changed
if (existingSubscriptionInfo.AppServerKey != applicationServerKey)
{
// We need to destroy the WNS channel and create a new one
// Close the channel
channel.Close();
// Create a new one
channel = await PushNotificationChannelManager.GetDefault().CreateRawPushNotificationChannelWithAlternateKeyForApplicationAsync(appServerKeyBuffer, channelId);
// And set existing subscription info to null since there's no longer existing info
existingSubscriptionInfo = null;
}
else
{
// Otherwise, return the existing info
return(new PushSubscription()
{
Endpoint = channel.Uri,
Keys = new PushSubscriptionKeys()
{
Auth = existingSubscriptionInfo.Keys.Auth,
P256DH = existingSubscriptionInfo.Keys.P256DH
},
Channel = channel,
ExpirationTime = channel.ExpirationTime
});
}
}
// Note that we have to store a series of these key pairs...
// A developer with an existing channel might call Subscribe again, generating a new channel and key pair,
// but they fail to upload the channel/key to their server. Therefore, their server still has the old channel/key,
// and pushing to that channel still needs to work, so we need to hold onto the old keys.
// We can't delete the old keys until either (1) the expiration time of 30 days for the channel occurs,
// or (2) we've received and decrypted a push with the newer key pair, and can therefore throw away the old keys, since
// we know at that point that the server successfully received the new channel/key.
// Although in case (2), the app developer could still hold onto a previous channel and use it, so the only real truth is the
// expiration time. Other than that, any channel that we return MUST keep working.
// However, W3C spec states that once a message has been received for a newer subscription, the old ones MUST be deactivated,
// so (2) is the correct pattern
// Otherwise, we have to create new pairs for this new channel
string p256dh;
var keyPair = GenerateKeyPair();
p256dh = Uint8ArrayToB64String(SubjectPublicKeyInfoFactory.CreateSubjectPublicKeyInfo(keyPair.Public).PublicKeyData.GetBytes());
var authBytes = CryptographicBuffer.GenerateRandom(16).ToArray();
string auth = Uint8ArrayToB64String(authBytes);
await storage.SavePushSubscriptionAsync(channelId, new StoredPushSubscription()
{
ChannelUri = channel.Uri,
Keys = new PushSubscriptionKeys()
{
Auth = auth,
P256DH = p256dh
},
AppServerKey = applicationServerKey,
P265Private = Uint8ArrayToB64String(PrivateKeyInfoFactory.CreatePrivateKeyInfo(keyPair.Private).ToAsn1Object().GetDerEncoded())
});
return(new PushSubscription()
{
Endpoint = channel.Uri,
Keys = new PushSubscriptionKeys()
{
Auth = auth,
P256DH = p256dh
},
Channel = channel,
ExpirationTime = channel.ExpirationTime
});
}
