# Subscribing to push notifications

For a push notification to reach a user, the user (or device) must be subscribed to receive push notifications on one or more notification channels. The application must also obtain a device token, which permits Mobile Backend Services (MBS) to communicate with the push service provider (Google Cloud Messaging (GCM), Firebase Cloud Messaging (FCM), or Apple Push Notification). Firebase Cloud Messaging (opens new window) (FCM) is the new version of GCM. This guide explains how to how obtain a device token, and how to use the PushNotifications API to manage your user's notification subscriptions.

# Obtaining a device token

To receive push notifications, your application first needs to obtain a device token. To obtain a device token:

• On iOS, call theTitanium.Network.registerForPushNotifications()

Once your application has obtained a device token it should save it for later use.

# Obtaining a device token on iOS

To obtain a device token on iOS, call theTitanium.Network.registerForPushNotifications()and setup callbacks for the success, error, and callback events. You can also specify the types of notifications enabled for your application, which can include one or more of the following: NOTIFICATION_TYPE_ALERT, NOTIFICATION_TYPE_BADGE, NOTIFICATION_TYPE_NEWSSTAND , or NOTIFICATION_TYPE_SOUND.

You need to register the user notification types you want to use with the Titanium.App.iOS.registerUserNotificationSettings()method before calling the registerForPushNotifications() method.

var deviceToken = null;

// Wait for user settings to be registered before registering for push notifications
Ti.App.iOS.addEventListener('usernotificationsettings', function registerForPush() {

    // Remove event listener once registered for push notifications
    Ti.App.iOS.removeEventListener('usernotificationsettings', registerForPush);

    Ti.Network.registerForPushNotifications({
        success: deviceTokenSuccess,
        error: deviceTokenError,
        callback: receivePush
    });
});

// Register notification types to use
Ti.App.iOS.registerUserNotificationSettings({
    types: [
        Ti.App.iOS.USER_NOTIFICATION_TYPE_ALERT,
        Ti.App.iOS.USER_NOTIFICATION_TYPE_SOUND,
        Ti.App.iOS.USER_NOTIFICATION_TYPE_BADGE
    ]
});

// Process incoming push notifications
function receivePush(e) {
    alert('Received push: ' + JSON.stringify(e));
}
// Save the device token for subsequent API calls
function deviceTokenSuccess(e) {
    deviceToken = e.deviceToken;
}

function deviceTokenError(e) {
    alert('Failed to register for push notifications! ' + e.error);
}

# Using Firebase

You can use Firebase (Firebase Cloud Messaging) for push notifications. The module is available at https://github.com/hansemannn/titanium-firebase-cloud-messaging and you can find a full tutorial at from zero to app (opens new window)