[#71] Weighing: Fix reconnection behaviour when COM port is connected/disconnected

Elwig/App.xaml.cs

@@ -149,7 +149,7 @@ namespace Elwig {
                 } catch (Exception e) {
                     list.Add(new InvalidScale(s.Id));
                     if (s.Required)
-                        MessageBox.Show($"Verbindung zu Waage {s.Id} konnte nicht hergestellt werden:\n\n{e.Message}", "Waagen-Fehler",
+                        MessageBox.Show($"Verbindung zu Waage {s.Id} konnte nicht hergestellt werden:\n\n{e.Message}", "Waagenfehler",
                             MessageBoxButton.OK, MessageBoxImage.Error);
                 }
             }
@@ -249,15 +249,19 @@ namespace Elwig {
         private void OnSerialPortConnected(object? sender, string name) {
             for (var i = 0; i < Config.Scales.Count; i++) {
                 var s = Config.Scales[i];
-                if ((s.Connection?.StartsWith($"serial://{name}:") ?? false) && Scales[i] is InvalidScale) {
+                if (s.Connection?.StartsWith($"serial://{name}:") ?? false) {
+                    if (Scales[i] is InvalidScale) {
                         try {
                             Scales[i] = Scale.FromConfig(s);
                             MessageBox.Show($"Verbindung zu Waage {s.Id} wieder hergestellt!", $"Waage {s.Id}", MessageBoxButton.OK, MessageBoxImage.Information);
                         } catch (Exception e) {
                             Scales[i] = new InvalidScale(s.Id);
-                        MessageBox.Show($"Verbindung zu Waage {s.Id} konnte nicht hergestellt werden:\n\n{e.Message}", "Waagen-Fehler",
+                            MessageBox.Show($"Verbindung zu Waage {s.Id} konnte nicht hergestellt werden:\n\n{e.Message}", "Waagenfehler",
                                 MessageBoxButton.OK, MessageBoxImage.Error);
                         }
+                    } else if (Scales[i] is IEventScale) {
+                        MessageBox.Show($"Verbindung zu Waage {s.Id} wieder hergestellt!", $"Waage {s.Id}", MessageBoxButton.OK, MessageBoxImage.Information);
+                    }
                 }
             }
             UpdateScales();
@@ -268,6 +272,7 @@ namespace Elwig {
                 var s = Config.Scales[i];
                 if ((s.Connection?.StartsWith($"serial://{name}:") ?? false) && Scales[i] is not InvalidScale) {
                     MessageBox.Show($"Verbindung zu Waage {s.Id} unterbrochen!", $"Waagen {s.Id}", MessageBoxButton.OK, MessageBoxImage.Warning);
+                    if (Scales[i] is ICommandScale) {
                         try {
                             Scales[i].Dispose();
                         } catch {
@@ -276,6 +281,7 @@ namespace Elwig {
                         Scales[i] = new InvalidScale(s.Id);
                     }
                 }
+            }
             UpdateScales();
         }
 

Elwig/Helpers/SerialPortWatcher.cs

@@ -17,28 +17,34 @@ namespace Elwig.Helpers {
         public SerialPortWatcher() {
             _knownPorts = SerialPort.GetPortNames();
             _deviceArrivalWatcher = new ManagementEventWatcher("SELECT * FROM Win32_DeviceChangeEvent WHERE EventType = 2");
-            _deviceArrivalWatcher.EventArrived += (s, e) => OnDeviceArrived();
+            _deviceArrivalWatcher.EventArrived += OnDeviceArrived;
             _deviceRemovalWatcher = new ManagementEventWatcher("SELECT * FROM Win32_DeviceChangeEvent WHERE EventType = 3");
-            _deviceRemovalWatcher.EventArrived += (s, e) => OnDeviceRemoved();
+            _deviceRemovalWatcher.EventArrived += OnDeviceRemoved;
             _deviceArrivalWatcher.Start();
             _deviceRemovalWatcher.Start();
 
         }
 
-        private void OnDeviceArrived() {
+        private void OnDeviceArrived(object sender, EventArrivedEventArgs evt) {
+            App.MainDispatcher.Invoke(() => {
+                // "synchronized"
                 string[] currentPorts = SerialPort.GetPortNames();
                 var newPorts = currentPorts.Except(_knownPorts).ToArray();
                 foreach (var port in newPorts)
                     SerialPortConnected?.Invoke(this, port);
                 _knownPorts = currentPorts;
+            });
         }
 
-        private void OnDeviceRemoved() {
+        private void OnDeviceRemoved(object sender, EventArrivedEventArgs evt) {
+            App.MainDispatcher.Invoke(() => {
+                // "synchronized"
                 string[] currentPorts = SerialPort.GetPortNames();
                 var removedPorts = _knownPorts.Except(currentPorts).ToArray();
                 foreach (var port in removedPorts)
                     SerialPortDisconnected?.Invoke(this, port);
                 _knownPorts = currentPorts;
+            });
         }
 
         public void Dispose() {

Elwig/Helpers/Weighing/AveryEventScale.cs

@@ -15,15 +15,17 @@ namespace Elwig.Helpers.Weighing {
         public bool IsReady { get; private set; }
         public bool HasFillingClearance { get; private set; }
 
-        public event IEventScale.EventHandler<WeighingEventArgs> WeighingEvent;
+        public event IEventScale.EventHandler<WeighingEventArgs>? WeighingEvent;
 
         private bool IsRunning = true;
         private readonly Thread BackgroundThread;
+        private readonly string Connection;
 
-        public AveryEventScale(string id, string model, string cnx, string? empty = null, string? filling = null, int? limit = null, string? log = null) :
+        public AveryEventScale(string id, string model, string cnx, string? log = null, bool required = true) :
-            base(cnx, empty, filling, limit, log) {
+            base(cnx, null, null, null, log, true, !required) {
             ScaleId = id;
             Model = model;
+            Connection = cnx;
             IsReady = true;
             HasFillingClearance = false;
             Stream.WriteTimeout = -1;
@@ -50,19 +52,49 @@ namespace Elwig.Helpers.Weighing {
                     var data = await Receive();
                     if (data != null)
                         RaiseWeighingEvent(new WeighingEventArgs(data.Value));
+                } catch (ThreadInterruptedException) {
+                    // ignore
+                } catch (IOException) {
+                    await Task.Delay(500);
+                    await Reconnect();
+                } catch (TimeoutException) {
+                    await Task.Delay(500);
+                    await Reconnect();
                 } catch (Exception ex) {
-                    MessageBox.Show($"Beim Wiegen ist ein Fehler Aufgetreten:\n\n{ex.Message}", "Waagenfehler",
+                    MessageBox.Show($"Beim Wiegen ist ein Fehler Aufgetreten:\n\n{ex.Message} ({ex.GetType().Name})", "Waagenfehler",
                         MessageBoxButton.OK, MessageBoxImage.Error);
                 }
             }
         }
 
+        protected async Task Reconnect() {
+            try { Reader.Close(); } catch { }
+            try { Stream.Close(); } catch { }
+            try { Serial?.Close(); } catch { }
+            while (IsRunning) {
+                try {
+                    if (Connection.StartsWith("serial:")) {
+                        Serial = Utils.OpenSerialConnection(Connection);
+                        Stream = Serial.BaseStream;
+                    } else if (Connection.StartsWith("tcp:")) {
+                        Tcp = Utils.OpenTcpConnection(Connection);
+                        Stream = Tcp.GetStream();
+                    }
+                    Reader = new(Stream, Encoding.ASCII, false, 512);
+                    break;
+                } catch {
+                    // ignore
+                }
+                await Task.Delay(1000);
+            }
+        }
+
         protected async Task<WeighingResult?> Receive() {
             var line = "";
             while (line.Length < 33) {
                 var ch = Reader.Read();
                 if (ch == -1) {
-                    return null;
+                    throw new IOException("Connection closed");
                 } else if (line.Length > 0 || ch == ' ') {
                     line += char.ToString((char)ch);
                 }
@@ -71,7 +103,7 @@ namespace Elwig.Helpers.Weighing {
             if (line == null || line == "") {
                 return null;
             } else if (line.Length != 33 || line[0] != ' ' || line[9] != ' ' || line[15] != ' ' || line[20] != ' ' || line[32] != ' ') {
-                throw new IOException($"Invalid event from scale: '{line}'");
+                throw new FormatException($"Invalid event from scale: '{line}'");
             }
 
             var date    = line[ 1.. 9];
@@ -81,7 +113,7 @@ namespace Elwig.Helpers.Weighing {
             var unit    = line[30..32];
 
             if (unit != "kg") {
-                throw new IOException($"Unsupported unit in weighing event: '{unit}'");
+                throw new WeighingException($"Unsupported unit in weighing event: '{unit}'");
             }
 
             identNr = identNr.Length > 0 && identNr != "0" ? identNr : null;

Elwig/Helpers/Weighing/GassnerScale.cs

@@ -36,7 +36,7 @@ namespace Elwig.Helpers.Weighing {
             var line = await Reader.ReadUntilAsync('\x03');
             if (LogPath != null) await File.AppendAllTextAsync(LogPath, $"{line}\r\n");
             if (line == null || line.Length < 4 || !line.StartsWith('\x02')) {
-                throw new IOException("Invalid response from scale");
+                throw new FormatException("Invalid response from scale");
             }
 
             var status = line[1..3];
@@ -45,9 +45,9 @@ namespace Elwig.Helpers.Weighing {
                 switch (status[1]) {
                     case 'M': msg = "Waage in Bewegung"; break;
                 }
-                throw new IOException($"Waagenfehler {status}: {msg}");
+                throw new WeighingException($"Waagenfehler {status}: {msg}");
             } else if (status[0] != ' ') {
-                throw new IOException($"Invalid response from scale (error code {status})");
+                throw new WeighingException($"Invalid response from scale (error code {status})");
             }
 
             return line[1..^1];
@@ -57,7 +57,7 @@ namespace Elwig.Helpers.Weighing {
             await SendCommand(incIdentNr ? '\x05' : '?');
             string record = await ReceiveResponse();
             if (record.Length != 45)
-                throw new IOException("Invalid response from scale: Received record has invalid size");
+                throw new FormatException("Invalid response from scale: Received record has invalid size");
             var line = record[2..];
 
             var brutto  = line[ 0.. 7].Trim();

Elwig/Helpers/Weighing/Scale.cs

@@ -1,8 +1,9 @@
-using System.IO.Ports;
-using System.IO;
-using System.Net.Sockets;
 using System;
+using System.IO;
+using System.IO.Ports;
+using System.Net.Sockets;
 using System.Text;
+using System.Windows;
 
 namespace Elwig.Helpers.Weighing {
     public abstract class Scale : IDisposable {
@@ -27,7 +28,7 @@ namespace Elwig.Helpers.Weighing {
             if (config.Type == "SysTec-IT") {
                 return new SysTecITScale(config.Id, config.Model!, config.Connection!, config.Empty, config.Filling, limit, config.Log);
             } else if (config.Type == "Avery-Async") {
-                return new AveryEventScale(config.Id, config.Model!, config.Connection!, config.Empty, config.Filling, limit, config.Log);
+                return new AveryEventScale(config.Id, config.Model!, config.Connection!, config.Log, config.Required);
             } else if (config.Type == "Gassner") {
                 return new GassnerScale(config.Id, config.Model!, config.Connection!, config.Empty, config.Filling, limit, config.Log);
             } else {
@@ -35,10 +36,17 @@ namespace Elwig.Helpers.Weighing {
             }
         }
 
-        protected Scale(string cnx, string? empty, string? filling, int? limit, string? log) {
+        protected Scale(string cnx, string? empty, string? filling, int? limit, string? log, bool softFail = false, bool failSilent = false) {
             if (cnx.StartsWith("serial:")) {
+                try {
                     Serial = Utils.OpenSerialConnection(cnx);
-                Stream = Serial.BaseStream;
+                } catch (Exception e) {
+                    if (!softFail) throw;
+                    if (!failSilent)
+                        MessageBox.Show($"Verbindung zu Waage konnte nicht hergestellt werden:\n\n{e.Message}", "Waagenfehler",
+                            MessageBoxButton.OK, MessageBoxImage.Warning);
+                }
+                Stream = Serial?.BaseStream ?? Stream.Null;
             } else if (cnx.StartsWith("tcp:")) {
                 Tcp = Utils.OpenTcpConnection(cnx);
                 Stream = Tcp.GetStream();

Elwig/Helpers/Weighing/SysTecITScale.cs

@@ -34,14 +34,14 @@ namespace Elwig.Helpers.Weighing {
             var line = await Reader.ReadUntilAsync("\r\n");
             if (LogPath != null) await File.AppendAllTextAsync(LogPath, line);
             if (line == null || line.Length < 4 || !line.StartsWith('<') || !line.EndsWith(">\r\n")) {
-                throw new IOException("Invalid response from scale");
+                throw new FormatException("Invalid response from scale");
             }
 
             var error = line[1..3];
             string msg = $"Unbekannter Fehler (Fehler code {error})";
             if (error[0] == '0') {
                 if (error[1] != '0') {
-                    throw new IOException($"Invalid response from scale (error code {error})");
+                    throw new WeighingException($"Invalid response from scale (error code {error})");
                 }
             } else if (error[0] == '1') {
                 switch (error[1]) {
@@ -52,21 +52,21 @@ namespace Elwig.Helpers.Weighing {
                     case '6': msg = "Drucker nicht bereit"; break;
                     case '7': msg = "Druckmuster enthält ungültiges Kommando"; break;
                 }
-                throw new IOException($"Waagenfehler {error}: {msg}");
+                throw new WeighingException($"Waagenfehler {error}: {msg}");
             } else if (error[0] == '2') {
                 switch (error[1]) {
                     case '0': msg = "Brutto negativ"; break;
                 }
-                throw new IOException($"Fehler {error}: {msg}");
+                throw new WeighingException($"Fehler {error}: {msg}");
             } else if (error[0] == '3') {
                 switch (error[1]) {
                     case '1': msg = "Übertragunsfehler"; break;
                     case '2': msg = "Ungültiger Befehl"; break;
                     case '3': msg = "Ungültiger Parameter"; break;
                 }
-                throw new IOException($"Kommunikationsfehler {error}: {msg}");
+                throw new WeighingException($"Kommunikationsfehler {error}: {msg}");
             } else {
-                throw new IOException($"Invalid response from scale (error code {error})");
+                throw new WeighingException($"Invalid response from scale (error code {error})");
             }
 
             return line[1..^3];
@@ -76,7 +76,7 @@ namespace Elwig.Helpers.Weighing {
             await SendCommand(incIdentNr ? $"RN{InternalScaleNr}" : $"RM{InternalScaleNr}");
             string record = await ReceiveResponse();
             if (record.Length != 62)
-                throw new IOException("Invalid response from scale: Received record has invalid size");
+                throw new FormatException("Invalid response from scale: Received record has invalid size");
             var line = record[2..];
 
             var status     = line[ 0.. 2];
@@ -94,9 +94,9 @@ namespace Elwig.Helpers.Weighing {
             var crc16      = line[52..60].Trim();
 
             if (Utils.CalcCrc16Modbus(record[..54]) != ushort.Parse(crc16)) {
-                throw new IOException($"Invalid response from scale: Invalid CRC16 checksum ({crc16} != {Utils.CalcCrc16Modbus(record[..54])})");
+                throw new WeighingException($"Invalid response from scale: Invalid CRC16 checksum ({crc16} != {Utils.CalcCrc16Modbus(record[..54])})");
             } else if (unit != "kg") {
-                throw new IOException($"Unsupported unit in weighing response: '{unit}'");
+                throw new WeighingException($"Unsupported unit in weighing response: '{unit}'");
             }
 
             identNr = identNr.Length > 0 && identNr != "0" ? identNr : null;

Elwig/Helpers/Weighing/WeighingException.cs

@@ -0,0 +1,6 @@
+using System;
+
+namespace Elwig.Helpers.Weighing {
+    class WeighingException(string? message = null) : Exception(message) {
+    }
+}