AmazonSimpleNotificationServiceClient - How to PublishRequest with TargetArn that contains Custom Payload without "default" value?

Question

I have:

1. Written a running Android App that recieved FCM notification.
2. Setup Amazon SNS: Mobile:Push notifications.
3. I am able to publish message using Amazon SNS Console through "Custom payload for each delivery protocol".

{ "GCM": "{ "data": { "MyTitle": "Sample endpoints", "MyMessage": "Important" } }" }

Amazon SNS Console - Publish Message

4. My running Android App is able to recieve the message with "data" only. This is what I expected to recieve.

"{MyTitle=Sample endpoints, MyMessage=Important}"

Android Studio - Message received

5. Wrote a .NET application using "AmazonSimpleNotificationServiceClient" [AWSSDK.SimpleNotificationService 3.7.4.3] to publish request, trying to do the exact same way to publish message like Amazon SNS Console. I am able to published successfully.

Visual studio .NET Application

6. My running Android App recieved the message but the message is wrapped within the "default" attribute. This is not expected, I want the same message I recieved from the Amazon SNS Console.

{default={"GCM": "{ "data": {"MyTitle": "Sample endpoints", "MyMessgae" : "Criticald" } } " }}

Android Studio - Message received

7. I tried to utilize PublishRequest.MessageSturcture to "json" (this requires "default" attribute before it can be published). I removed that, the message automatically wrapped with "default".
8. How do I send custom raw message from .NET Application the same way I can send "Custom Payload for each delivery protocol" from Amazon SNS Console? I want to publish to the "platform endpoint ARN".

Answer 1

Sending the message from the AWS Console is different from sending the message using AmazonSimpleNotificationServiceClient.

You will need to construct "PublishRequest" object.

• Set "MessageStructure = json"
• Use TargetArn / TopicArn.
• Message = needs to be in specific format. It is mandatory to have "default" member with dummy data follow by "GCM" or "APNS" ... The content of the "GCM" is a string and not child node.

This is a working code:

        // Android Payload
        string payload = "\\\"data\\\":{\\\"MyTitle\\\":\\\"test message \\\", \\\"MyMessage\\\": \\\"Important\\\"}";

        // iOS Payload
        //string payload = "\\\"notification\\\" : {\\\"content_available\\\" : true }, \\\"data\\\": { \\\"MyTitle\\\": \\\"Sample message for iOS endpoints\\\", \\\"MyMessage\\\":\\\"Hello world\\\",\\\"Payload\\\": {\\\"InstructionID\\\": \\\"f7a87860-11f4-47e1-8a39-3da2ffd6eadb\\\",\\\"IsAlert\\\": false,\\\"Content\\\": \\\"This is new content\\\",\\\"Value\\\": 2.554,\\\"Counter\\\": 290,\\\"DateTime\\\": \\\"2022-09-11T16:13:57.2009482Z\\\"}}";
        var request = new PublishRequest
        {   
            Message = "{\"default\": \"default message\",\"GCM\":\"{" + payload + "}\"}",
            TargetArn = fcmARN,
            MessageStructure = "json"
        };
        
        try
        {
            var response = await snsClient.PublishAsync(request);
            if (response.HttpStatusCode.Equals(HttpStatusCode.OK))
                Console.WriteLine("Message Sent to Topic");
            else
                Console.WriteLine("Failed - Message Sent to Topic");
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex);
        }

Example Message: enter image description here