How to intercept AWS SNS messages to iOs mobile endpoints in Xamarin? - amazon-web-services

Question

The documentation on AWS -SNS for use of SNS within Xamarin iOS projects shows how to register an iOS device to receive messages from SNS, but not clear how to intercept those messages within the application and programtically respond to the message. How do I capture the incoming message, and process appropriately rather than just showing the text of the message received? Is this done by sending a different message than is shown in the AWS console, and where can I intercept it in my application?
This is the example I've been following:
public override bool FinishedLaunching(UIApplication app, NSDictionary options) {
// do something
var pushSettings = UIUserNotificationSettings.GetSettingsForTypes (
UIUserNotificationType.Alert |
UIUserNotificationType.Badge |
UIUserNotificationType.Sound,
null
);
app.RegisterUserNotifications(pushSettings);
app.RegisterForRemoteNotifications();
// do something
return true;
}
public override void RegisteredForRemoteNotifications(UIApplication application, NSData token) {
var deviceToken = token.Description.Replace("<", "").Replace(">", "").Replace(" ", "");
if (!string.IsNullOrEmpty(deviceToken)) {
//register with SNS to create an endpoint ARN
var response = await SnsClient.CreatePlatformEndpointAsync(
new CreatePlatformEndpointRequest {
Token = deviceToken,
PlatformApplicationArn = "YourPlatformArn" /* insert your platform application ARN here */
});
}
}
Here is the message I'm sending:
{
"APNS_SANDBOX":"{\"aps\":{\"alert\":\"This is my message\"}}"
}
This seems to work fine for displaying a text message sent from the AWS console, whether the app is running or not, but that's not what I need for my app. (e.g. a chess app, where the SNS messages are used to exchange moves made by a pair of users and the app displays them.)
The FinishedLaunching method contains several not altogether helpful "do something" , but I can't figure out how to, say call some method in my PCL when a particular message is received and pass the content of the message to that method.

Answer 1

You can subscribe the DidReceiveRemoteNotification() event in AppDelegate.cs to get your content you sent on SNS.
public override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
{
// retrieve something from a server somewhere
}
This event will trigger when user taps the notification to open the app and when this app is on background state or foreground state.
If this app is closed this event will not trigger, but we can also get the content in public override bool FinishedLaunching(UIApplication app, NSDictionary options) with the parameter options.
Moreover if you want to get it in PCL, we can make a MessagingCenter to achieve this:
Send content on native platform:
MessagingCenter.Send<object, NSDictionary>(this, "Notification", userInfo);
Then receive this MessagingCenter on PCL somewhere you like:
MessagingCenter.Subscribe<object, NSDictionary>(this, "Notification", (sender, dic) =>
{
});