CODEWITHSUNDEEP
iosflutterpush-notificationchatend-to-end-encryption
Rohit Kokate
Rohit Kokate

Reputation: 11

How to implement Notifications like WhatsApp for an E2EE Chat App built using Flutter?

I'm trying to send a Push Notification like any other messaging platform like WhatsApp, Telegram, etc. The message is supposed to be End-to-End Encrypted, so the encrypted message needs to be decrypted before showing in the notification banner in the mobile app using flutter_local_notifications. But the data messages are not received on iOS when the app is terminated. Only when a notification object with title or body is added in the payload, the message is received on iOS even in background or terminated state. But results in two notification banners for a message.

Read this in FlutterFire GithHub Discussion without success.

Push Notifications (Firebase) are triggered via AWS SNS: Mobile Push-Notifications. Here's the code invoking Push Notification with payload.

const payload = {
  GCM: JSON.stringify({
    data: {
      message: message
    },
    android: {
      priority: "high"
    },
    content_available: true
  }),
};

const params = {
  Message: JSON.stringify(payload),
  TargetArn: ENDPOINT_ARN,
  MessageStructure: 'json',
};

const publishCommand = new PublishCommand(params);

I highly doubt if WhatsApp, Telegram are actually using Push Notifications in their apps but some kind of background-service. But the background processing is still unpredictable on iOS. So what should be the notification solution for a E2EE chat app built using Flutter?

Upvotes: 0

Views: 115

Answers (1)

Mahmoud Gamal El-Din
Mahmoud Gamal El-Din

Reputation: 91

You will have to upgrade your flutter version for me 3.22.3

You will receive your notification in 
FirebaseMessaging.onBackgroundMessage

But we should be careful of many points

  • You should not open WebSocket

  • You should get your messages by making one HTTP request

  • You should do your work quickly as the IOS system will close your app at any time

  • this point happened to me: when checked for the internet it closed the app and didn't complete the work

  • Sometimes the IOS system will block your app when you try many times so it sometimes doesn't work after sending a lot of FCM

  • please read this comment also about how sometimes the message may not received in ios https://github.com/firebase/flutterfire/issues/9563#issuecomment-1259318869

  • this is backend server side

      admin.messaging().send({data,token,android: {priority: 'high',data,}, apns: {
payload: {
  aps: {
    contentAvailable: true,
    mutableContent: true,
    priority: 'high',
  },
},
headers: {
  'apns-push-type': 'background',
  'apns-priority': '5',
  'bundleIdentifier': 'com.example.packageId', // Replace with 
 your app's bundle identifier
},

    }, })

Upvotes: 0

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