Merge pull request #428 from twonlyapp/hotfix_ack

fix infinite loop issue with receipts

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.5.2
+
+- Hotfix: Fixed an infinite loop involving delivery receipts
+
 ## 0.5.1
 
 - Improve: Show delivery and read receipt indicators for text messages

lib/src/database/daos/receipts.dao.dart

@@ -250,6 +250,25 @@ class ReceiptsDao extends DatabaseAccessor<TwonlyDB> with _$ReceiptsDaoMixin {
         null;
   }
 
+  /// Claims a new delivery-receipt attempt after [cooldown] has elapsed.
+  ///
+  /// Updating the timestamp before sending prevents repeated server batches from
+  /// starting multiple delivery-receipt attempts during the same cooldown.
+  Future<bool> claimDuplicateReceiptResend(
+    String receiptId,
+    Duration cooldown,
+  ) async {
+    final now = clock.now();
+    final updated =
+        await (update(receivedReceipts)..where(
+              (t) =>
+                  t.receiptId.equals(receiptId) &
+                  t.createdAt.isSmallerOrEqualValue(now.subtract(cooldown)),
+            ))
+            .write(ReceivedReceiptsCompanion(createdAt: Value(now)));
+    return updated > 0;
+  }
+
   Future<void> gotReceipt(String receiptId) async {
     await into(
       receivedReceipts,

lib/src/services/api/api.service.dart

@@ -299,9 +299,17 @@ class ApiService {
     return result;
   }
 
-  Future<void> sendResponse(ClientToServer response) async {
+  Future<bool> sendResponse(ClientToServer response) async {
-    if (_channel != null) {
+    final channel = _channel;
-      _channel!.sink.add(response.writeToBuffer());
+    if (channel == null || channel.closeCode != null) {
+      return false;
+    }
+    try {
+      channel.sink.add(response.writeToBuffer());
+      return true;
+    } catch (e) {
+      Log.warn('Could not send response to server: $e');
+      return false;
     }
   }
 

lib/src/services/api/server_messages.api.dart

@@ -80,9 +80,16 @@ Future<void> handleServerMessage(server.ServerToClient msg) async {
     ..seq = msg.v0.seq
     ..response = response;
 
-  await apiService.sendResponse(ClientToServer()..v0 = v0);
+  final responseSent = await apiService.sendResponse(ClientToServer()..v0 = v0);
+  if (responseSent) {
+    Log.info(
+      'Successfully queued response for server message ${msg.v0.seq}.',
+    );
+  } else {
+    Log.warn('Could not send response for server message ${msg.v0.seq}.');
+  }
   AppState.gotMessageFromServer = true;
-  Log.info('All messages from the server proccessed.');
+  Log.info('All messages from the server processed.');
 }
 
 DateTime lastPushKeyRequest = clock.now().subtract(const Duration(hours: 1));
@@ -141,8 +148,25 @@ Future<void> _handleClient2ClientMessage(
   }
 
   if (await twonlyDB.receiptsDao.isDuplicated(receiptId)) {
+    if (message.type == Message_Type.SENDER_DELIVERY_RECEIPT) {
       Log.info(
-      '[$receiptId] Message is a duplicate. Sending delivery receipt again.',
+        '[$receiptId] Delivery receipt is a duplicate. Skipping receipt response.',
+      );
+      return;
+    }
+    const duplicateReceiptCooldown = Duration(days: 10);
+    final shouldResend = await twonlyDB.receiptsDao.claimDuplicateReceiptResend(
+      receiptId,
+      duplicateReceiptCooldown,
+    );
+    if (!shouldResend) {
+      Log.info(
+        '[$receiptId] Message is a duplicate. Skipping delivery receipt during cooldown.',
+      );
+      return;
+    }
+    Log.info(
+      '[$receiptId] Message is a duplicate and cooldown elapsed. Sending delivery receipt again.',
     );
     try {
       final response = Message(type: Message_Type.SENDER_DELIVERY_RECEIPT);

pubspec.yaml

@@ -3,7 +3,7 @@ description: "twonly, a privacy-friendly way to connect with friends through sec
 
 publish_to: 'none'
 
-version: 0.5.1+171
+version: 0.5.2+172
 
 environment:
   sdk: ^3.11.0