send idempotency keys with redirect checkout

android/app/src/main/kotlin/org/getlantern/lantern/handler/MethodHandler.kt

@@ -470,7 +470,8 @@ class MethodHandler : FlutterPlugin,
                         val url = Mobile.paymentRedirect(
                             map["provider"] as String,
                             map["planId"] as String,
-                            map["email"] as String
+                            map["email"] as String,
+                            map["idempotencyKey"] as? String ?: ""
                         )
                         withContext(Dispatchers.Main) {
                             success(url)

lantern-core/core.go

@@ -119,10 +119,10 @@
 	StripeBillingPortalUrl() (string, error)
 	AcknowledgeGooglePurchase(purchaseToken, planId string) (string, error)
 	AcknowledgeApplePurchase(receipt, planII string) (string, error)
-	PaymentRedirect(provider, planID, email string) (string, error)
+	PaymentRedirect(provider, planID, email, idempotencyKey string) (string, error)
 	ActivationCode(email, resellerCode string) error
 	SubscriptionPaymentRedirectURL(redirectBody account.PaymentRedirectData) (string, error)
-	StripeSubscriptionPaymentRedirect(subscriptionType, planID, email string) (string, error)
+	StripeSubscriptionPaymentRedirect(subscriptionType, planID, email, idempotencyKey string) (string, error)
 }
 
 type SplitTunnel interface {
@@ -866,25 +866,27 @@
 	return lc.client.SubscriptionPaymentRedirectURL(lc.ctx, redirectBody)
 }
 
-func (lc *LanternCore) StripeSubscriptionPaymentRedirect(subscriptionType, planID, email string) (string, error) {
+func (lc *LanternCore) StripeSubscriptionPaymentRedirect(subscriptionType, planID, email, idempotencyKey string) (string, error) {
 	deviceID := lc.MyDeviceId()
 	redirectBody := account.PaymentRedirectData{
-		Provider:    "stripe",
-		Plan:        planID,
-		DeviceName:  deviceID,
-		Email:       email,
-		BillingType: account.SubscriptionType(subscriptionType),
+		Provider:       "stripe",
+		Plan:           planID,
+		DeviceName:     deviceID,
+		Email:          email,
+		BillingType:    account.SubscriptionType(subscriptionType),
+		IdempotencyKey: idempotencyKey,
 	}
 	return lc.SubscriptionPaymentRedirectURL(redirectBody)
 }
 
-func (lc *LanternCore) PaymentRedirect(provider, planId, email string) (string, error) {
+func (lc *LanternCore) PaymentRedirect(provider, planId, email, idempotencyKey string) (string, error) {
 	deviceName := lc.MyDeviceId()
 	body := account.PaymentRedirectData{
-		Provider:   provider,
-		Plan:       planId,
-		DeviceName: deviceName,
-		Email:      email,
+		Provider:       provider,
+		Plan:           planId,
+		DeviceName:     deviceName,
+		Email:          email,
+		IdempotencyKey: idempotencyKey,
 	}
 	return lc.client.PaymentRedirect(lc.ctx, body)
 }

lantern-core/ffi/ffi.go

@@ -633,16 +633,17 @@ func fetchUserData() *C.char {
 // Fetch stipe subscription payment redirect link
 //
 //export stripeSubscriptionPaymentRedirect
-func stripeSubscriptionPaymentRedirect(subType, _planId, _email *C.char) *C.char {
+func stripeSubscriptionPaymentRedirect(subType, _planId, _email, _idempotencyKey *C.char) *C.char {
 	subscriptionType := C.GoString(subType)
 	planID := C.GoString(_planId)
 	email := C.GoString(_email)
+	idempotencyKey := C.GoString(_idempotencyKey)
 	return runOnGoStack(func() *C.char {
 		c, errStr := requireCore()
 		if errStr != nil {
 			return errStr
 		}
-		redirect, err := c.StripeSubscriptionPaymentRedirect(subscriptionType, planID, email)
+		redirect, err := c.StripeSubscriptionPaymentRedirect(subscriptionType, planID, email, idempotencyKey)
 		if err != nil {
 			return SendError(err)
 		}
@@ -653,16 +654,17 @@ func stripeSubscriptionPaymentRedirect(subType, _planId, _email *C.char) *C.char
 // Fetch payment redirect link for providers like alipay
 //
 //export paymentRedirect
-func paymentRedirect(_plan, _provider, _email *C.char) *C.char {
+func paymentRedirect(_plan, _provider, _email, _idempotencyKey *C.char) *C.char {
 	plan := C.GoString(_plan)
 	provider := C.GoString(_provider)
 	email := C.GoString(_email)
+	idempotencyKey := C.GoString(_idempotencyKey)
 	return runOnGoStack(func() *C.char {
 		c, errStr := requireCore()
 		if errStr != nil {
 			return errStr
 		}
-		redirect, err := c.PaymentRedirect(provider, plan, email)
+		redirect, err := c.PaymentRedirect(provider, plan, email, idempotencyKey)
 		if err != nil {
 			return SendError(err)
 		}

lantern-core/mobile/mobile.go

@@ -555,17 +555,18 @@ func AcknowledgeApplePurchase(receipt, planII string) (string, error) {
 	})
 }
 
-func PaymentRedirect(provider, planId, email string) (string, error) {
-	return withCoreR(func(c lanterncore.Core) (string, error) { return c.PaymentRedirect(provider, planId, email) })
-
+func PaymentRedirect(provider, planId, email, idempotencyKey string) (string, error) {
+	return withCoreR(func(c lanterncore.Core) (string, error) {
+		return c.PaymentRedirect(provider, planId, email, idempotencyKey)
+	})
 }
 
 // /This is specifically for stripe subscriptions that require a redirect to complete the payment
 // This is only used for macos
-func StripeSubscriptionPaymentRedirect(subType, planId, email string) (string, error) {
+func StripeSubscriptionPaymentRedirect(subType, planId, email, idempotencyKey string) (string, error) {
 	slog.Debug("stripeSubscriptionPaymentRedirect called")
 	return withCoreR(func(c lanterncore.Core) (string, error) {
-		return c.StripeSubscriptionPaymentRedirect(subType, planId, email)
+		return c.StripeSubscriptionPaymentRedirect(subType, planId, email, idempotencyKey)
 	})
 }
 

lib/core/common/common.dart

@@ -83,6 +83,14 @@ String generatePassword() {
   ).join();
 }
 
+String generatePaymentRedirectIdempotencyKey() {
+  final random = Random.secure();
+  return List.generate(
+    16,
+    (_) => random.nextInt(256).toRadixString(16).padLeft(2, '0'),
+  ).join();
+}
+
 bool isStoreVersion() {
   if (!PlatformUtils.isMobile) {
     return false;

lib/features/plans/provider/payment_notifier.dart

@@ -54,12 +54,14 @@ class PaymentNotifier extends _$PaymentNotifier {
     String planId,
     String email,
   ) async {
+    final idempotencyKey = generatePaymentRedirectIdempotencyKey();
     return ref
         .read(lanternServiceProvider)
         .stipeSubscriptionPaymentRedirect(
           type: type,
           planId: planId,
           email: email,
+          idempotencyKey: idempotencyKey,
         );
   }
 
@@ -77,9 +79,15 @@ class PaymentNotifier extends _$PaymentNotifier {
     required String planId,
     required String email,
   }) async {
+    final idempotencyKey = generatePaymentRedirectIdempotencyKey();
     return ref
         .read(lanternServiceProvider)
-        .paymentRedirect(provider: provider, planId: planId, email: email);
+        .paymentRedirect(
+          provider: provider,
+          planId: planId,
+          email: email,
+          idempotencyKey: idempotencyKey,
+        );
   }
 
   Future<Either<Failure, String?>> startUpgradeFlow({

lib/lantern/lantern_core_service.dart

@@ -84,17 +84,19 @@ abstract class LanternCoreService {
 
   Future<Either<Failure, String>> getOAuthProvider();
 
-
   ///Payments methods
-  Future<Either<Failure, String>> stipeSubscriptionPaymentRedirect(
-      {required BillingType type,
-      required String planId,
-      required String email});
+  Future<Either<Failure, String>> stipeSubscriptionPaymentRedirect({
+    required BillingType type,
+    required String planId,
+    required String email,
+    required String idempotencyKey,
+  });
 
   Future<Either<Failure, String>> paymentRedirect({
     required String provider,
     required String planId,
     required String email,
+    required String idempotencyKey,
   });
 
   // this is used for stripe subscription

lib/lantern/lantern_ffi_service.dart

@@ -738,6 +738,7 @@ class LanternFFIService implements LanternCoreService {
     required BillingType type,
     required String planId,
     required String email,
+    required String idempotencyKey,
   }) async {
     try {
       appLogger.debug('Starting Stripe Subscription Payment Redirect');
@@ -747,6 +748,7 @@ class LanternFFIService implements LanternCoreService {
               type.name.toCharPtr,
               planId.toCharPtr,
               email.toCharPtr,
+              idempotencyKey.toCharPtr,
             )
             .toDartString();
       });
@@ -889,6 +891,7 @@ class LanternFFIService implements LanternCoreService {
     required String provider,
     required String planId,
     required String email,
+    required String idempotencyKey,
   }) async {
     try {
       final result = await runInBackground<String>(() async {
@@ -897,6 +900,7 @@ class LanternFFIService implements LanternCoreService {
               planId.toCharPtr,
               provider.toCharPtr,
               email.toCharPtr,
+              idempotencyKey.toCharPtr,
             )
             .toDartString();
       });

lib/lantern/lantern_generated_bindings.dart

@@ -5669,8 +5669,14 @@ class LanternBindings {
     ffi.Pointer<ffi.Char> subType,
     ffi.Pointer<ffi.Char> _planId,
     ffi.Pointer<ffi.Char> _email,
+    ffi.Pointer<ffi.Char> _idempotencyKey,
   ) {
-    return _stripeSubscriptionPaymentRedirect(subType, _planId, _email);
+    return _stripeSubscriptionPaymentRedirect(
+      subType,
+      _planId,
+      _email,
+      _idempotencyKey,
+    );
   }
 
   late final _stripeSubscriptionPaymentRedirectPtr =
@@ -5680,6 +5686,7 @@ class LanternBindings {
             ffi.Pointer<ffi.Char>,
             ffi.Pointer<ffi.Char>,
             ffi.Pointer<ffi.Char>,
+            ffi.Pointer<ffi.Char>,
           )
         >
       >('stripeSubscriptionPaymentRedirect');
@@ -5690,15 +5697,17 @@ class LanternBindings {
               ffi.Pointer<ffi.Char>,
               ffi.Pointer<ffi.Char>,
               ffi.Pointer<ffi.Char>,
+              ffi.Pointer<ffi.Char>,
             )
           >();
 
   ffi.Pointer<ffi.Char> paymentRedirect(
     ffi.Pointer<ffi.Char> _plan,
     ffi.Pointer<ffi.Char> _provider,
     ffi.Pointer<ffi.Char> _email,
+    ffi.Pointer<ffi.Char> _idempotencyKey,
   ) {
-    return _paymentRedirect(_plan, _provider, _email);
+    return _paymentRedirect(_plan, _provider, _email, _idempotencyKey);
   }
 
   late final _paymentRedirectPtr =
@@ -5708,6 +5717,7 @@ class LanternBindings {
             ffi.Pointer<ffi.Char>,
             ffi.Pointer<ffi.Char>,
             ffi.Pointer<ffi.Char>,
+            ffi.Pointer<ffi.Char>,
           )
         >
       >('paymentRedirect');
@@ -5717,6 +5727,7 @@ class LanternBindings {
           ffi.Pointer<ffi.Char>,
           ffi.Pointer<ffi.Char>,
           ffi.Pointer<ffi.Char>,
+          ffi.Pointer<ffi.Char>,
         )
       >();
 

lib/lantern/lantern_platform_service.dart

@@ -651,6 +651,7 @@ class LanternPlatformService implements LanternCoreService {
     required BillingType type,
     required String planId,
     required String email,
+    required String idempotencyKey,
   }) async {
     if (!PlatformUtils.isMacOS) {
       return left(
@@ -663,7 +664,12 @@ class LanternPlatformService implements LanternCoreService {
     try {
       final redirectUrl = await _methodChannel.invokeMethod<String>(
         'stripeSubscriptionPaymentRedirect',
-        {"type": type.name, "planId": planId, "email": email},
+        {
+          "type": type.name,
+          "planId": planId,
+          "email": email,
+          "idempotencyKey": idempotencyKey,
+        },
       );
       return Right(redirectUrl!);
     } catch (e) {
@@ -758,14 +764,20 @@ class LanternPlatformService implements LanternCoreService {
     required String provider,
     required String planId,
     required String email,
+    required String idempotencyKey,
   }) async {
     if (PlatformUtils.isIOS) {
       throw UnimplementedError("This not supported on IOS");
     }
     try {
       final redirectUrl = await _methodChannel.invokeMethod<String>(
         'paymentRedirect',
-        {'provider': provider, 'planId': planId, 'email': email},
+        {
+          'provider': provider,
+          'planId': planId,
+          'email': email,
+          'idempotencyKey': idempotencyKey,
+        },
       );
       return Right(redirectUrl!);
     } catch (e, stackTrace) {

lib/lantern/lantern_service.dart

@@ -175,18 +175,21 @@ class LanternService implements LanternCoreService {
     required BillingType type,
     required String planId,
     required String email,
+    required String idempotencyKey,
   }) {
     if (PlatformUtils.isFFISupported) {
       return _ffiService.stipeSubscriptionPaymentRedirect(
         type: type,
         planId: planId,
         email: email,
+        idempotencyKey: idempotencyKey,
       );
     }
     return _platformService.stipeSubscriptionPaymentRedirect(
       type: type,
       planId: planId,
       email: email,
+      idempotencyKey: idempotencyKey,
     );
   }
 
@@ -354,18 +357,21 @@ class LanternService implements LanternCoreService {
     required String provider,
     required String planId,
     required String email,
+    required String idempotencyKey,
   }) {
     if (PlatformUtils.isFFISupported) {
       return _ffiService.paymentRedirect(
         provider: provider,
         planId: planId,
         email: email,
+        idempotencyKey: idempotencyKey,
       );
     }
     return _platformService.paymentRedirect(
       provider: provider,
       planId: planId,
       email: email,
+      idempotencyKey: idempotencyKey,
     );
   }