Fix crash on reconnect & ignore rtt topic ID (#8)

* Ensure proper cleanup when reconnecting * wait for rtt to connect before continuing * ignore rtt message topic ID * update version and changelog
mjansen4857 · Dec 22, 2023 · cb432be · cb432be
1 parent 75f1f42
commit cb432be
Show file tree

Hide file tree

Showing 3 changed files with 32 additions and 15 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 1.3.2
+
+- Fix crash on reconnecting to server
+- Ignore rtt protocol topic ID
+
 ## 1.3.1
 
 - Fix connections being timed out too quickly

diff --git a/lib/src/nt4_client.dart b/lib/src/nt4_client.dart
@@ -45,7 +45,9 @@ class NT4Client {
   int _timeoutInterval = _pingTimeoutMsV40;
 
   WebSocketChannel? _mainWebsocket;
+  StreamSubscription<dynamic>? _mainWebsocketSub;
   WebSocketChannel? _rttWebsocket;
+  StreamSubscription<dynamic>? _rttWebsocketSub;
 
   /// Create an NT4 client. This will connect to an NT4 server running at
   /// [serverBaseAddress]. This should be either 'localhost' if running a
@@ -450,14 +452,14 @@ class NT4Client {
       _useRTT = true;
       _pingInterval = _pingIntervalMsV41;
       _timeoutInterval = _pingTimeoutMsV41;
-      _rttConnect();
+      await _rttConnect();
     } else {
       _useRTT = false;
       _pingInterval = _pingIntervalMsV40;
       _timeoutInterval = _pingTimeoutMsV40;
     }
 
-    _mainWebsocket!.stream.listen(
+    _mainWebsocketSub = _mainWebsocket!.stream.listen(
       (data) {
         if (!_serverConnectionActive) {
           _lastAnnouncedValues.clear();
@@ -470,10 +472,11 @@ class NT4Client {
       },
       onDone: _wsOnClose,
       onError: (err) {},
+      cancelOnError: true,
     );
 
     NT4Topic timeTopic = NT4Topic(
-        name: "Time",
+        name: 'Time',
         type: NT4TypeStr.typeInt,
         id: -1,
         pubUID: -1,
@@ -500,7 +503,7 @@ class NT4Client {
     }
   }
 
-  void _rttConnect() async {
+  Future<void> _rttConnect() async {
     if (!_useRTT || _rttConnectionActive) {
       return;
     }
@@ -523,32 +526,34 @@ class NT4Client {
 
     _rttConnectionActive = true;
 
-    _rttWebsocket!.stream.listen(
+    _rttWebsocketSub = _rttWebsocket!.stream.listen(
       (data) {
         if (data is! List<int>) {
           return;
         }
 
         var msg = Unpacker.fromList(data).unpackList();
 
-        int topicID = msg[0] as int;
+        // rtt socket will only send timestamps, we can ignore the topic ID
         int timestampUS = msg[1] as int;
         var value = msg[3];
 
         if (value is! int) {
           return;
         }
 
-        if (topicID == -1) {
-          _wsHandleRecieveTimestamp(timestampUS, value);
-        }
+        _wsHandleRecieveTimestamp(timestampUS, value);
       },
       onDone: _rttOnClose,
+      onError: (error) {},
+      cancelOnError: true,
     );
   }
 
-  void _rttOnClose() {
-    _rttWebsocket?.sink.close();
+  void _rttOnClose() async {
+    await _rttWebsocketSub?.cancel();
+    _rttWebsocketSub = null;
+    await _rttWebsocket?.sink.close();
     _rttWebsocket = null;
 
     _lastReceivedTime = 0;
@@ -557,9 +562,16 @@ class NT4Client {
     _useRTT = false;
   }
 
-  void _wsOnClose() {
-    _mainWebsocket?.sink.close();
-    _rttWebsocket?.sink.close();
+  void _wsOnClose() async {
+    _pingTimer?.cancel();
+    _pongTimer?.cancel();
+
+    await _mainWebsocketSub?.cancel();
+    _mainWebsocketSub = null;
+    await _mainWebsocket?.sink.close();
+    await _rttWebsocketSub?.cancel();
+    _rttWebsocketSub = null;
+    await _rttWebsocket?.sink.close();
 
     _mainWebsocket = null;
     _rttWebsocket = null;

diff --git a/pubspec.yaml b/pubspec.yaml
@@ -1,6 +1,6 @@
 name: nt4
 description: Dart implementation of the WPILib NT4 protocol
-version: 1.3.1
+version: 1.3.2
 repository: https://github.com/mjansen4857/nt4
 
 environment: