Flutter SDK

Chargebee's Flutter SDK enables you to build a seamless and efficient customer experience for your subscription business.

Post-installation, initialization, and authentication with the Chargebee site, this SDK will support the following process.

• Sync In-App Subscriptions with Chargebee: Integrate your App developed on Flutter with Chargebee to process and track in-app subscriptions of the Apple App Store and Google Play Store on your Chargebee account. Thus you can create a single source of truth for subscriptions across Apple, Google, and Web stores. Use this if you are selling digital goods or services or are REQUIRED to use Apple's and Google's in-app purchases as per their app review guidelines (Apple and Google). For SDK methods to work, ensure that prerequisites (Apple and Google) are configured in Chargebee.

Requirements

The following requirements must be set up before installing Chargebee's Flutter SDK.

• Flutter version 2.10.0 and above
• Dart SDK version 2.16.2 and above
• Android Gradle Plugin 4.0.0
• Gradle 6.1.1+
• AndroidX
• Java 8+ and Kotlin
• iOS 12+
• Swift 5+

Installation

To use Chargebee SDK in your Flutter app, follow these steps:

1. Add Chargebee as a dependency in your pubspec.yamlfile.

   dependencies: 
    chargebee_flutter: ^0.4.2

2. Install dependency.

   flutter pub get

Configuring SDK

Prerequisites Before configuring the Chargebee Flutter SDK for syncing In-App Purchases, follow these steps.

1. iOS: Integrate the Apple App Store account with your Chargebee site.
   Android: Integrate Google Play Store account with your Chargebee site.
2. iOS: On theSync Overview pageof theweb app, click View Keys and use the value of generated App ID as the SDK Key.
   Android: On the Sync Overview page of the web app, click Set up notifications and use the generated App ID value as the SDK Key.
3. On the Chargebee site, navigate to Configure Chargebee > API Keys to create a new Publishable API Key or use an existing Publishable API Key.

Note: During the publishable API key creation you must allow read-only access to plans/items otherwise this key will not work in the following snippet. Read more.

Initialize the Chargebee Flutter SDK with your Chargebee site, Publishable API Key, and SDK Keys by including the following snippets in your app delegate during app startup.

import 'package:chargebee_flutter/chargebee_flutter.dart';
try {
  await Chargebee.configure("SITE_NAME", "API-KEY", "iOS SDK Key", "Android SDK Key");
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

Integrating In-App Purchases

This section describes how to use the SDK to integrate In-App Purchase information. For details on In-App Purchase, read more.

Get all IAP Product Identifiers from Chargebee

Every In-App Purchase subscription product that you configure in your account, can be configured in Chargebee as a Plan. Start by retrieving the IAP Product IDs from your Chargebee account using the following function.

try {
  final result = await Chargebee.retrieveProductIdentifiers(queryparam);
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

For example, query parameters can be passed as "limit": "100".

Get IAP Products

Retrieve the IAP Product objects with Product IDs using the following function.

try {
  List<Product> products = await Chargebee.retrieveProducts({productList: "[Product ID's from Google or Apple]"});
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

You can present any of the above products to your users for them to purchase.

Buy or Subscribe Product

Pass the Product and CBCustomer objects to the following function when the user chooses the product to purchase.

CBCustomer - Optional object. Although this is an optional object, we recommend passing the necessary customer details, such as customerId, firstName, lastName, and email if it is available before the user subscribes to your App. This ensures that the customer details in your database match the customer details in Chargebee. If the customerId is not passed in the customer's details, then the value of customerId will be the same as the subscriptionId created in Chargebee.

Note: The customer parameter in the below code snippet is an instance of CBCustomer class that contains the details of the customer who wants to subscribe or buy the product.

try {
  final customer = CBCustomer('customerId','firstName','lastName','emailId');
  final result = await Chargebee.purchaseStoreProduct(product, customer: customer);
  print("subscription id : ${result.subscriptionId}");
  print("subscription status : ${result.status}");
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

The above function will handle the purchase against Apple App Store or Google Play Store and send the in-app purchase receipt for server-side receipt verification to your Chargebee account. Use the Subscription ID returned by the above function to check for Subscription status on Chargebee and confirm the access - granted or denied.

Invoke Show Manage Subscriptions Settings

For Android

The showManageSubscriptionsSettings() function is designed to invoke the Manage Subscriptions in your app using Chargebee's Flutter SDKs. Chargebee.showManageSubscriptionsSettings(), opens the Play Store App subscriptions settings page.

For iOS

The showManageSubscriptionsSettings() function is designed to invoke the upgrade/downgrade flow in your app using Chargebee's Flutter SDKs. Chargebee.shared.showManageSubscriptionsSettings(), opens the App Store App subscriptions settings page.

Note: Upgrades and downgrades are handled through Apple App Store Server Notifications in Chargebee.

Upgrade or Downgrade Subscription

When a user changes their subscription level from a lower price plan to a higher price plan, it's considered an upgrade. On the other hand, when a user switches from a higher-price plan to a lower-price plan, it's considered a downgrade. In the case of the Apple App Store, you can arrange the subscriptions using the drag-and-drop option in Edit Subscription Order in App Store Connect. Learn more.

One-Time Purchases

The purchaseNonSubscriptionProduct function handles the one-time purchase against Apple App Store and Google Play Store and then sends the IAP receipt for server-side receipt verification to your Chargebee account. Post verification a Charge corresponding to this one-time purchase will be created in Chargebee. The Apple App Store supports three types of one-time purchases consumable, non_consumable and non_renewing_subscription. The Google Play Store supports two types of one-time purchases consumable and non_consumable.

try {
  final productType = OneTimeProductType.consumable;
  final customer = CBCustomer('id','','','');
  final result = await Chargebee.purchaseNonSubscriptionProduct(product, productType, customer);
  debugPrint('invoice id : ${result.invoiceId}');
  debugPrint('charge id : ${result.chargeId}');
  debugPrint('customer id : ${result.customerId}');
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

The given code defines a function named purchaseNonSubscriptionProduct in the Chargebee class, which takes three input parameters:

• product: An instance of Product class, representing the product to be purchased from the Apple App Store or Google Play Store.
• customer: Optional. An instance of CBCustomer class, initialized with the customer's details such as customerId, firstName, lastName, and email.
• productType: An enum instance of productType type, indicating the type of product to be purchased. It can be either .consumable, or non_consumable, or non_renewing_subscription. Currently non_renewing_subscription product type supports only in Apple App Store.

The function is called asynchronously, and it returns a Result object with a success or failure case, as mentioned are below.

• If the purchase is successful, it returns NonSubscriptionPurchaseResult object. which includes the invoiceId, chargeId, and customerId associated with the purchase.
• If there is any failure during the purchase, it returns PlatformException. which includes an error object that can be used to handle the error.

Restore Purchases

The restorePurchases() function helps to recover your app user's previous purchases without making them pay again. Sometimes, your app user may want to restore their previous purchases after switching to a new device or reinstalling your app. You can use the restorePurchases() function to allow your app user to easily restore their previous purchases.

To retrieve inactive purchases along with the active purchases for your app user, you can call the restorePurchases() function with the includeInactivePurchases parameter set to true. If you only want to restore active subscriptions, set the parameter to false. Here is an example of how to use the restorePurchases() function in your code with the includeInactivePurchases parameter set to true.

try {
  final result = await Chargebee.restorePurchases(true);
  print("result : $result");
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

Return Subscriptions Object

The restorePurchases() function returns an array of subscription objects and each object holds three attributes subscriptionId, planId, and storeStatus. The value of storeStatus can be used to verify subscription status.

Error Handling

In the event of any failures while finding associated subscriptions for the restored items, The SDK will return an error, as mentioned in the following table.

These are the possible error codes and their descriptions:

Error Code	Description
2014	This error occurs when the user attempts to restore a purchase, but there is no receipt associated with the purchase.
2015	This error occurs when the attempt to refresh the receipt for a purchase fails.
2016	This error occurs when the attempt to restore a purchase fails for reasons other than a missing or invalid receipt.
2017	This error occurs when the URL for the receipt bundle provided during the restore process is invalid or cannot be accessed.
2018	This error occurs when the data contained within the receipt is not valid or cannot be parsed.
2019	This error occurs when there are no products available to restore.
2020	This error occurs when there is an error with the Chargebee service during the restore process.

Synchronization of Apple App Store/Google Play Store Purchases with Chargebee through Receipt Validation

Receipt validation is crucial to ensure that the purchases made by your users are synced with Chargebee. In rare cases, when a purchase is made at the Apple App Store/Google Play Store, and the network connection goes off or the server not responding, the purchase details may not be updated in Chargebee. In such cases, you can use a retry mechanism by following these steps:

• Add a network listener, as shown in the example project.
• Save the product identifier in the cache once the purchase is initiated and clear the cache once the purchase is successful.
• When the network connectivity is lost after the purchase is completed at Apple App Store/Google Play Store but not synced with Chargebee, retrieve the product from the cache once the network connection is back and initiate validateReceipt() / validateReceiptForNonSubscriptions() by passing productId and CBCustomer(optional) as input. This will validate the receipt and sync the purchase in Chargebee as a subscription or one-time purchase. For subscriptions, use the function to validateReceipt();for one-time purchases, use the function validateReceiptForNonSubscriptions().

Use the function available for the retry mechanism.

Function for validating the Subscriptions receipt

try {
  final customer = CBCustomer('customerId','firstName','lastName','emailId');
  final result = await Chargebee.validateReceipt(productId, customer);
  print("subscription id : ${result.subscriptionId}");
  print("subscription status : ${result.status}");
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

Function for validating the One-Time Purchases receipt

try {
  final productType = OneTimeProductType.consumable;
  final customer = CBCustomer('id','','','');
  final result = await Chargebee.validateReceiptForNonSubscriptions(productId, productType, customer);
  debugPrint('invoice id : ${result.invoiceId}');
  debugPrint('charge id : ${result.chargeId}');
  debugPrint('customer id : ${result.customerId}');
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

Get Subscription Status for Existing Subscribers using Query Parameters

Use this method to check the subscription status of a subscriber who has already purchased the product.

Use query parameters - Subscription ID, Customer ID, or Status for checking the Subscription status on Chargebee and confirm the access - granted or denied.

try {
  final result = await Chargebee.retrieveSubscriptions(queryparam);
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

For example, query parameters can be passed as "customer_id" : "id", "subscription_id": "id", or "status": "active".

Retrieve Entitlements of a Subscription

Use the query parameter - Subscription ID for retrieving the list of entitlements associated with the subscription.

try {
  final result = await Chargebee.retrieveEntitlements(queryparam);
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

For example, query parameters can be passed as "subscriptionId": "id".

Note: Entitlements feature is available only if your Chargebee site is on Product Catalog 2.0.

Get all items

If your Chargebee site is configured to Product Catalog 2.0, use the following functions to retrieve the item list.

try {
  final result = await Chargebee.retrieveAllItems(queryparam);
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

For example, query parameters can be passed as "sort_by[desc]" : "name" or "limit": "100".

Get All Plans

If your Chargebee site is configured to Product Catalog 1.0, use the relevant functions to retrieve the plan list.

try {
  final result = await Chargebee.retrieveAllPlans(queryparam);
} on PlatformException catch (e) {
  print('Error Message: ${e.message}, Error Details: ${e.details}, Error Code: ${e.code}');
}

For example, query parameters can be passed as "sort_by[desc]" : "name" or "limit": "100".

License

Chargebee is available under the MIT license. For more information, see the LICENSE file.