[firebase_messaging] data message not triggering onMessage on foreground

[kabychow]

Everything works perfectly fine when i send a notification message

JSON for notification message:

{
   "priority": "high",
   "notification": {
      "title": "Title",
      "body": "Body"
   },
   "data": {
      "click_action": "FLUTTER_NOTIFICATION_CLICK",
      "another_key": "mydata"
   },
   "to": "<my_fcmtoken>"
}

But onMessage event stops triggering when I send a data message (removing the notification key)

JSON for data message:

{
   "priority": "high",
   "data": {
      "click_action": "FLUTTER_NOTIFICATION_CLICK",
      "another_key": "mydata"
   },
   "to": "<my_fcmtoken>"
}

both getting success=1 from the google fcm response

This issue happens to me on iOS device (I don't have an Android device to test if it happens on Android)
I am using firebase_messaging 4.0.0+1

[ZatacaSystems]

here is the solution @cgfischer @Khaibin

[cgfischer]

I have the same problem with onMessage not being called on data messages under iOS. In all test cases the Android and iOS flutter app is running in foreground. Messages with the "notification" work fine on both Android and iOS but when I remove the notification element and send just a "data" message, then the iOS application does not receive the onMessage callback.

In my case I am using python on my back-end server to publish notification messages. The python code looks like:

                msg = firebase_messaging.Message(
                    android=firebase_messaging.AndroidConfig(
                        priority='high', ttl=30.0),
                    apns=firebase_messaging.APNSConfig(
                        headers={'apns-priority': '10'}),
                    data=data_message,
                    # notification=firebase_messaging.Notification(
                    #    title='GC Runner data',
                    #    body=data_message['op']),
                    token=fcm_token)
                rc = firebase_messaging.send(msg)

Everything works fine (iOS and Android receive onMessage callback) when the notification parameter is passed into the Message constructor. When I comment out this parameter (as shown) then the iOS app stops receiving the onMessage callback.

Here is my flutter doctor output:

C:\projects\mobile\golfdb>flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel beta, v1.4.9-hotfix.1, on Microsoft Windows [Version 10.0.17134.706], locale en-US)
[√] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
[√] Android Studio (version 3.3)
[√] VS Code, 64-bit edition (version 1.33.1)
[√] Connected device (2 available)

• No issues found!

Here is my pubspec.yaml:

C:\projects\mobile\golfdb>type pubspec.yaml
name: golfdb
description: A new Flutter project.

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# Read more about versioning at semver.org.
version: 1.0.0+14

environment:
  sdk: ">=2.1.0-dev.5.0 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  intl: ^0.15.7

  shared_preferences: ^0.4.3
  flutter_secure_storage: ^3.1.2
  device_info: ^0.2.1
  http: ^0.11.3
  cached_network_image: ^0.5.1
  flutter_cache_manager: ^0.2.0
  uuid: ^1.0.3
  charts_flutter: ^0.5.0
  flutter_markdown: ^0.2.0
  path_provider: ^0.4.1
  audioplayers: ^0.7.8
  keyboard_visibility: ^0.5.1

  firebase_core: ^0.3.4
  firebase_messaging: ^4.0.0+3
  firebase_analytics: ^2.1.1+3

  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^0.1.2

dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_launcher_icons: "^0.7.0"

flutter_icons:
  image_path: "icons/icon-test.png"
  android: true
  ios: true

# For information on the generic Dart part of this file, see the
# following page: https://www.dartlang.org/tools/pub/pubspec

# The following section is specific to Flutter.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #  - images/a_dot_burr.jpeg
  #  - images/a_dot_ham.jpeg
  assets:

[github-actions]

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