[firebase_messaging]: iOS devices never receive data-only message

[Pedrozena]

Is there an existing issue for this?

• I have searched the existing issues.

Are you aware of the differences between iOS and Android background message handling?

• I understand that iOS and Android background messages behave differently, and I've designed my application with that in mind.

Do you have an active Apple Developer account?

• I have an active Apple Developer account.

Are you using a physical iOS device to test background messages?

• I am using a physical iOS device to test background messages.

Have you enabled "Remote Notifications" & "Background Mode" (Checking options for "Background Processing" & "Remote Notifications") in your app's Xcode project?

Have you created an APNs key in your Apple Developer account & uploaded this APNs key to your Firebase console?

Have you disabled method swizzling for Firebase in your app?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key></key>
	<string></string>
	<key>NSBluetoothServices</key>
	<array>
		<string></string>
	</array>
	<key>CFBundleDisplayName</key>
	<string></string>
	<key>FirebaseDynamicLinksCustomDomains</key>
	<array>
		<string>https://----</string>
	</array>
	<key>LSApplicationCategoryType</key>
	<string></string>
	<key>GADApplicationIdentifier</key>
	<string>ca-app-pub--------</string>
	<key>LSApplicationQueriesSchemes</key>
	<array>
		<string>fbapi</string>
		<string>fb-messenger-api</string>
		<string>fbauth2</string>
		<string>fbshareextension</string>
	</array>
	<key>CFBundleInfoDictionaryVersion</key>
	<string>6.0</string>
	<key>BGTaskSchedulerPermittedIdentifiers</key>
	<array>
		<string>dev.flutter.background.refresh</string>
	</array>
	<key>CADisableMinimumFrameDurationOnPhone</key>
	<true/>
	<key>CFBundleDevelopmentRegion</key>
	<string>$(DEVELOPMENT_LANGUAGE)</string>
	<key>CFBundleExecutable</key>
	<string>$(EXECUTABLE_NAME)</string>
	<key>CFBundleIconName</key>
	<string>AppIcon</string>
	<key>CFBundleIdentifier</key>
	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
	<key>CFBundleName</key>
	<string>.....</string>
	<key>CFBundlePackageType</key>
	<string>APPL</string>
	<key>CFBundleShortVersionString</key>
	<string>$(FLUTTER_BUILD_NAME)</string>
	<key>CFBundleSignature</key>
	<string>????</string>
	<key>CFBundleURLTypes</key>
	<array>
		<dict>
			<key>CFBundleURLSchemes</key>
			<array>
				<string>com.googleusercontent.apps-----</string>
			</array>
		</dict>
		<dict>
			<key>CFBundleTypeRole</key>
			<string>Editor</string>
			<key>CFBundleURLName</key>
			<string>-----</string>
			<key>CFBundleURLSchemes</key>
			<array>
				<string>------</string>
			</array>
		</dict>
	</array>
	<key>CFBundleVersion</key>
	<string>$(FLUTTER_BUILD_NUMBER)</string>
	<key>FacebookAppID</key>
	<string>-------</string>
	<key>FacebookClientToken</key>
	<string>-------</string>
	<key>FacebookDisplayName</key>
	<string>com.....app</string>
	<key>FirebaseAppDelegateProxyEnabled</key>
	<string>YES</string>
	<key>ITSAppUsesNonExemptEncryption</key>
	<false/>
	<key>LSRequiresIPhoneOS</key>
	<true/>
	<key>NSAppTransportSecurity</key>
	<dict>
		<key>NSAllowsLocalNetworking</key>
		<true/>
	</dict>
	<key>NSBluetoothAlwaysUsageDescription</key>
	<string>bluetooth</string>
	<key>NSBluetoothPeripheralUsageDescription</key>
	<string>bluetooth</string>
	<key>NSCameraUsageDescription</key>
	<string>Allow access to camera to capture photos</string>
	<key>NSLocationAlwaysAndWhenInUseUsageDescription</key>
	<string>This app always needs location and when in use to function</string>
	<key>NSLocationAlwaysUsageDescription</key>
	<string>This app always needs location to function</string>
	<key>NSLocationWhenInUseUsageDescription</key>
	<string>This app needs location when in use to function</string>
	<key>NSMicrophoneUsageDescription</key>
	<false/>
	<key>NSPhotoLibraryAddUsageDescription</key>
	<string>App needs access to photo lib</string>
	<key>NSPhotoLibraryUsageDescription</key>
	<string>Allow access to photo library</string>
	<key>UIApplicationSupportsIndirectInputEvents</key>
	<true/>
	<key>UIBackgroundModes</key>
	<array>
		<string>fetch</string>
		<string>processing</string>
		<string>remote-notification</string>
	</array>
	<key>UILaunchStoryboardName</key>
	<string>LaunchScreen</string>
	<key>UIMainStoryboardFile</key>
	<string>Main</string>
	<key>UISupportedInterfaceOrientations</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
		<string>UIInterfaceOrientationLandscapeLeft</string>
		<string>UIInterfaceOrientationLandscapeRight</string>
	</array>
	<key>UISupportedInterfaceOrientations~ipad</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
		<string>UIInterfaceOrientationPortraitUpsideDown</string>
		<string>UIInterfaceOrientationLandscapeLeft</string>
		<string>UIInterfaceOrientationLandscapeRight</string>
	</array>
	<key>UIViewControllerBasedStatusBarAppearance</key>
	<string>true</string>
</dict>
</plist>

Are you sending messages to your app from the Firebase Admin SDK?

from firebase_admin import messaging
#firebase-admin           6.5.0

def send_message_to_token(data, token, notification=None):
    data = _convert_data(data)
    apns = None
    android = None
    if notification is not None:
        notification = messaging.Notification(**notification)
    else:
        apns = messaging.APNSConfig(
            payload=messaging.APNSPayload(
                aps=messaging.Aps(content_available=True, custom_data={"gcm.message_id": str(uuid.uuid4())})
            )
        )
        android = messaging.AndroidConfig(priority="high")    
    message = messaging.Message(data, notification=notification, token=token, apns=apns, android=android)
    messaging.send(message, app=get_app())
    logger.info(f"sent message to token: {token}")

Have you requested permission from the user to receive notifications?

• I have the relevant permission to receive notifications.

Have you used the 'Console' application on your macOS device to check if the iOS device's system is throttling your background messages?

No logs are printed so we can't tell if the message was delivered.

Additional context and comments

Android devices receive such messages, and iOS ones receive regular messages with non-null notifications.

While using legacy FCM api with the following payload:

{
  "to": token,
  "priority": "high",
  "content_available": true,
  "data": {
    "new_message": {
      "sender_uid": sender_uid,
      "message_payload": message,
    },
  },
}

the iOS devices regularly received also background messages.

[SelaseKay]

Hi @Pedrozena , What version of firebase_messaging are you experiencing this on?

[Pedrozena]

Hi @SelaseKay. We use:
firebase_messaging: ^15.0.1

[SelaseKay]

Kindly update to the latest version and try again.

[Pedrozena]

updating to version 15.1.3 doesn't solve the issue.

[Lyokone]

Hello @Pedrozena, if you are receiving normal notifications but not data only notifications, it's probably something to do with your setup since we are not doing anything between those 2.
I see that you are using the content_available key, is this the right key for the language you are using? In JS/TS you are supposed to use contentAvailable.
Also Apple doesn't guarantee that data only messages will be delivered, so you can get throttled while debugging this kind of feature.

[Pedrozena]

Yes, I'm using the official firebase_admin Python package, and that property is correct.
I opened the related issue there