Chumbaq Flutter SDK

Deep linking, deferred deep links, attribution, events, in-app messages, banners, and push notifications for Chumbaq.

Platform support

Android and iOS. The plugin pulls in the published native SDKs — from Maven Central on Android and through Swift Package Manager on iOS — so there is nothing to check out alongside it. iOS has one requirement; see iOS setup.

Anything that needs the native SDK throws UnsupportedError on web and desktop, with a message saying so, rather than failing quietly. Five members answer instead of throwing, because for each of them an answer is more useful than an exception:

Member	Where there is no native bridge
`Chumbaq.isInitialized`	`false`
`ChumbaqPush.isInitialized`	`false`
`ChumbaqPush.isRegistered`	`false`
`ChumbaqBannerCarousel`	renders `SizedBox.shrink()`
publishing to `Chumbaq.deepLinks`	drops the event

The first three are questions whose honest answer is "no" — making them throw would mean wrapping every feature check in a try. The carousel is a widget, and a widget cannot report an unsupported platform out of build without replacing the screen with an error box. The last is best-effort by design on every platform: it publishes only if something has already subscribed.

Three members are Android-only even now that the rest of the plugin runs on iOS. Each throws UnsupportedError there — none of them returns an empty stream or a quiet success:

Member	Why, and what to do on iOS
`ChumbaqPush.tokens`	APNs hands the device token to the host app's own app delegate, never to the plugin, so there is nothing to stream. Pass the token you receive to `ChumbaqPush.registerToken`.
`ChumbaqPush.registerMiPushToken`	Mi Push is a Xiaomi delivery channel, and Xiaomi handsets are Android handsets.
`ChumbaqBannerCarousel`	The widget hosts Android's native carousel view through a PlatformView. On iOS it renders `SizedBox.shrink()`; call `ChumbaqBanners.loadBanners` and build the carousel in Flutter.

Push engagement reporting is pure Dart over dart:io, so it needs only Chumbaq.init — on both platforms, and it worked on iOS before the rest of the plugin did.

To watch any of these do nothing, turn on diagnostics.

iOS setup

One hard requirement. It fails the build if unmet, before any of your code is compiled.

1. Swift Package Manager

The iOS plugin is a Swift package, with no podspec. The native iOS SDK it wraps ships as a Swift package and has no CocoaPods spec to depend on, so a pod could not pull it in.

Nothing to do on Flutter 3.44 or newer: Swift Package Manager has been on by default since 3.44.0, including on stable, and flutter config --list reporting enable-swift-package-manager: (Not set) means on. On an older Flutter, or a project where it was explicitly turned off, enable it once:

flutter config --enable-swift-package-manager

Without it there is no iOS support at all, and the build stops with the reason rather than a confusing no such module 'ChumbaqCore' later:

The following plugin(s) are only compatible with Swift Package Manager:
  - chumbaq

Minimum iOS: 14.0, level with the native SDK. Flutter 3.47 itself migrates host projects to a deployment target of 15.0, so in practice your app will be on 15.

Deep links

Two more steps, both specific to how iOS delivers links:

1. Register your custom scheme in ios/Runner/Info.plist, matching the customScheme you pass to ChumbaqConfig. Without it iOS never hands the URL to the app:

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLSchemes</key>
    <array><string>yourscheme</string></array>
  </dict>
</array>

2. For Universal Links, add the Associated Domains capability (applinks:your.chumbaq.host) and serve the matching apple-app-site-association file from that host.

The plugin registers for both the scene and the app-delegate URL callbacks, so a FlutterAppDelegate-based app needs no code of its own — including for a link that launched the app, which arrives before Chumbaq.init has run and is replayed to Chumbaq.deepLinks once it has.

Push

Push on iOS is APNs, and the host app owns registration:

func application(
  _ application: UIApplication,
  didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
) {
  let hex = deviceToken.map { String(format: "%02x", $0) }.joined()
  // Hand `hex` to Dart and call ChumbaqPush.instance.registerToken(hex).
}

Installation

dependencies:
  chumbaq: ^0.1.0

Getting started

final config = ChumbaqConfig.builder(
  baseUrl: 'https://your-chumbaq-host',
  apiKey: '<project API key>',
  projectId: '<project id>',
).build();

await Chumbaq.instance.init(config);

// Where a deep link should take the app.
Chumbaq.instance.deepLinks.listen((link) => router.go(link.url));

// After a fresh install, to claim the click that led to it.
final match = await Chumbaq.instance.matchDeferredDeepLink();

// Who this is, once they log in.
await Chumbaq.instance.identify(
  IdentifyParams.builder().externalUserId('u_42').build(),
);

In-app messages

ChumbaqMessages.instance.events.listen((event) => switch (event) {
  MessageLifecycleEvent(:final eventType) => log(eventType),
  MessageButtonAction(:final button) => router.go(button.actionUrl!),
  MessageCustomEvent(:final eventName) => analytics.track(eventName),
});

await ChumbaqMessages.instance.onAppOpen();
await ChumbaqMessages.instance.onScreenView('Home');
await ChumbaqMessages.instance.onEvent('purchase');

The native SDK draws the message — all five layouts, the picture, the theme and the buttons — so there is no Flutter widget to place. What arrives in Dart is the stream of what happened to it.

Push notifications

This SDK never intercepts a message. Firebase Messaging on Android, and APNs on iOS, are the app's; the SDK reports whatever the app hands it. On iOS that includes the device token itself — see iOS setup.

await ChumbaqPush.instance.init();

FirebaseMessaging.onMessage.listen(
  (message) => ChumbaqPush.instance.reportNotificationReceived(message.data),
);

FirebaseMessaging.onMessageOpenedApp.listen((message) async {
  // A tap also hands back the campaign's destination, if it has one.
  final url = await ChumbaqPush.instance.reportNotificationClicked(message.data);
  if (url != null) router.go(url);
});

The four engagement events

The backend accepts four, and each is a different column of a campaign's report. Only delivered and click have an obvious moment to hook; the other two are the app's to report, because Flutter is not what drew the notification.

Call	Reports	When
`reportNotificationReceived`	`delivered`	the device took the message
`reportNotificationImpression`	`impression`	the user could actually see it
`reportNotificationClicked`	`click`	they tapped it
`reportNotificationDismissed`	`dismissed`	they swiped it away

delivered is not impression: a push that arrives while notifications are blocked is delivered and never seen, and a click-through rate measured against deliveries flatters the campaign. dismissed is the only negative signal — without it a rejected notification looks like an ignored one.

All four take optional metadata, stored with the event and returned with the campaign's report.

Attributing an action-button tap

A button press is a click, but the campaign's report can only separate it from a tap on the body if the button's id comes along. Pass it as actionId; it is sent as metadata.actionId, the same key the Android SDK uses.

final actions = ChumbaqPush.actionsFrom(message.data);

final url = await ChumbaqPush.instance.reportNotificationClicked(
  message.data,
  actionId: actions.first.id,
);

The returned URL is the pressed button's own deepLinkUrl when it has one, and the campaign's destination otherwise.

Token updates — Android only

ChumbaqPush.instance.tokens.listen((token) => log('new push token: $token'));

Emits whenever Firebase issues a new registration token. Chumbaq has already registered it with the backend by then — the stream is for apps that need to do something of their own with it.

On iOS this throws UnsupportedError. APNs gives the device token to the host app's own application(_:didRegisterForRemoteNotificationsWithDeviceToken:) and never to the plugin, so there is nothing to stream; call ChumbaqPush.instance.registerToken with what you receive.

There is no replay: a refresh is an event, so a subscriber that starts listening afterwards sees nothing. A refresh delivered to a background service on a cold start, before Dart exists, is registered natively but has no stream to reach.

This rides on the plugin's own FirebaseMessagingService subclass, which the plugin's manifest installs in place of the native SDK's. An app that registers a service of its own instead should subclass ChumbaqFlutterMessagingService, or forward its onNewToken to ChumbaqFlutterMessagingService.publishToken(token).

Xiaomi devices — Android only

MIUI throttles background FCM hard enough that on Xiaomi handsets the vendor channel is the one that gets delivered. The app owns the Mi Push SDK — Chumbaq does not depend on Xiaomi's closed-source AAR — so add it to the Android build, call MiPushClient.registerPush, and hand the regId over:

await ChumbaqPush.instance.registerMiPushToken(regId);

This is an addition, not a replacement: the backend keeps both tokens, prefers the vendor channel, and still sends exactly one notification. A ChumbaqApiError with status 400 means the deployment has no Mi Push credentials configured.

Rich content is handed over as data, not drawn

Flutter has no notification UI of its own, and on Android the native SDK has already drawn the notification before Dart is running. So a campaign's extras are surfaced as typed models for the app to do what it likes with — attributing a tap to the button that caused it, or re-showing the same content in a screen:

final slides  = ChumbaqPush.carouselFrom(message.data);  // List<PushCarouselSlide>
final timer   = ChumbaqPush.timerFrom(message.data);     // PushTimer?
final actions = ChumbaqPush.actionsFrom(message.data);   // List<PushAction>
final image   = ChumbaqPush.imageUrlFrom(message.data);  // String?

Each of them answers empty or null for a payload that carries none, or carries one that cannot be read — malformed content costs the extras, never the notification.

imageUrlFrom is null for a campaign delivered over FCM, which carries an image field of its own that the Firebase client renders without help. It is non-null only where the client has to attach the picture itself.

Diagnostics

Almost nothing in this package throws at its caller. Engagement reporting must never cost an app a notification tap, a stream whose native listener fails to attach has to stay open, and a widget cannot throw out of build. The result is that a misconfigured integration looks exactly like a working one: calls return, streams stay open, and nothing happens.

ChumbaqDiagnostics.enabled = true;  // before Chumbaq.init

Turning this on makes those paths say so — which call went quiet, and whether it was a failure or a skip. Behaviour is identical either way; it is a debugging aid, not an error channel, and it is off by default.

Reports go to debugPrint. Send them somewhere else with ChumbaqDiagnostics.sink. Nothing logged carries an API key, a push token or a device fingerprint, so a report is safe to paste into an issue.

License

Licensed under the Apache License, Version 2.0.

Chumbaq Flutter SDK

Platform support

iOS setup

1. Swift Package Manager

Deep links

Push

Installation

Getting started

In-app messages

Push notifications

The four engagement events

Attributing an action-button tap

Token updates — Android only

Xiaomi devices — Android only

Rich content is handed over as data, not drawn

Diagnostics

License

Libraries

chumbaq package

Chumbaq Flutter SDK

Platform support

iOS setup

1. Swift Package Manager

Deep links

Push

Installation

Getting started

In-app messages

Push notifications

The four engagement events

Attributing an action-button tap

Token updates — Android only

Xiaomi devices — Android only

Rich content is handed over as data, not drawn

Diagnostics

Related SDKs

License

Libraries

chumbaq package