Verbesserung von Stabilität und Fehlerbehandlung

- Implementierung von `IDisposable` in der Klasse `Client`, um Ressourcen wie Timer und Kanäle ordnungsgemäß freizugeben.
- Einführung von `ActiveClients` und `ClientStatus` zur Verfolgung und Statusanzeige aktiver Clients.
- Verbesserte Fehlerbehandlung mit der Methode `HandleCommunicationError`, die Kommunikationsfehler protokolliert, den Client offline setzt und einen Reconnect auslöst.
- Optimierung der Reconnect-Logik mit asynchronen Wiederverbindungsversuchen und gestaffelten Verzögerungen.
- Erweiterung der Konstruktoren in `Client` um einen optionalen `pClientName`-Parameter und Generierung eines eindeutigen `ClientId`.
- Verbesserte Timer-Logik und asynchrone Verarbeitung in `UpdateTimer_Elapsed`.
- Einführung der Methode `EnsureAvailable`, um sicherzustellen, dass der Kanal vor Service-Aufrufen verfügbar ist.
- Hinzufügen asynchroner Varianten für Service-Methoden (`GetDatatable`, `GetScalarValue`, `ExecuteNonQuery`) und Fallback auf direkte Datenbankzugriffe.
- Verbesserte Timeout-Einstellungen und Verbindungsverwaltung in der Klasse `Channel`.
- Erweiterungen in `DatabaseWithFallback` für asynchrone Methoden und detaillierteres Logging.
- Aktualisierung der Assembly-Version auf `2.7.0`.

EDMIAPI/Client/Channel.vb

@@ -1,4 +1,5 @@
 Imports System.ServiceModel
+Imports System.Threading
 Imports System.Xml
 Imports DigitalData.Modules.Base
 Imports DigitalData.Modules.EDMI.API.EDMIServiceReference
@@ -10,31 +11,65 @@ Public Class Channel
     Private ReadOnly ChannelFactory As ChannelFactory(Of IEDMIServiceChannel)
 
     Public Event Reconnect As EventHandler
+    ' Verbindungszähler
+    Private Shared _ActiveConnections As Integer = 0
+    Public Shared ReadOnly Property ActiveConnections As Integer
+        Get
+            Return _ActiveConnections
+        End Get
+    End Property
 
     Public Shared Function GetBinding(Optional AuthenticationMode As TcpClientCredentialType = TcpClientCredentialType.Windows) As NetTcpBinding
         Return New NetTcpBinding() With {
-            .MaxReceivedMessageSize = Constants.ChannelSettings.MAX_RECEIVED_MESSAGE_SIZE,
-            .MaxBufferSize = Constants.ChannelSettings.MAX_BUFFER_SIZE,
-            .MaxBufferPoolSize = Constants.ChannelSettings.MAX_BUFFER_POOL_SIZE,
-            .TransferMode = TransferMode.Streamed,
-            .Security = New NetTcpSecurity() With {
-                .Mode = SecurityMode.Transport,
-                .Transport = New TcpTransportSecurity() With {
-                    .ClientCredentialType = AuthenticationMode
-                }
-            },
-            .ReaderQuotas = New XmlDictionaryReaderQuotas() With {
-                .MaxArrayLength = Constants.ChannelSettings.MAX_ARRAY_LENGTH,
-                .MaxStringContentLength = Constants.ChannelSettings.MAX_STRING_CONTENT_LENGTH
+        .MaxReceivedMessageSize = Constants.ChannelSettings.MAX_RECEIVED_MESSAGE_SIZE,
+        .MaxBufferSize = Constants.ChannelSettings.MAX_BUFFER_SIZE,
+        .MaxBufferPoolSize = Constants.ChannelSettings.MAX_BUFFER_POOL_SIZE,
+        .ListenBacklog = Constants.ChannelSettings.MAX_CONNECTIONS,
+        .MaxConnections = Constants.ChannelSettings.MAX_CONNECTIONS,
+        .TransferMode = TransferMode.Streamed,
+        .SendTimeout = TimeSpan.FromSeconds(30),      ' ← War: 5min → Schnellere Fehlererkennung
+        .ReceiveTimeout = TimeSpan.FromMinutes(10),   ' Keepalive < Firewall-Timeout (3600s) ✓
+        .OpenTimeout = TimeSpan.FromSeconds(30),      ' ← Neu: Verbindungsaufbau begrenzen
+        .CloseTimeout = TimeSpan.FromSeconds(30),
+        .Security = New NetTcpSecurity() With {
+            .Mode = SecurityMode.Transport,
+            .Transport = New TcpTransportSecurity() With {
+                .ClientCredentialType = AuthenticationMode
             }
+        },
+        .ReaderQuotas = New XmlDictionaryReaderQuotas() With {
+            .MaxArrayLength = Constants.ChannelSettings.MAX_ARRAY_LENGTH,
+            .MaxStringContentLength = Constants.ChannelSettings.MAX_STRING_CONTENT_LENGTH
         }
+    }
     End Function
 
     Public Sub New(pLogConfig As LogConfig, pServerAddress As ServerAddressStruct)
         MyBase.New(pLogConfig)
         ChannelFactory = GetChannelFactory(pServerAddress)
     End Sub
+    ''' <summary>
+    ''' Closes a channel gracefully, falls back to Abort on error
+    ''' </summary>
+    Public Shared Sub CloseChannel(pChannel As IEDMIServiceChannel)
+        If pChannel Is Nothing Then Return
 
+        Try
+            If pChannel.State = CommunicationState.Opened Then
+                pChannel.Close()
+            ElseIf pChannel.State = CommunicationState.Faulted OrElse
+                   pChannel.State = CommunicationState.Closing Then
+                pChannel.Abort()
+            End If
+            ' CommunicationState.Created / Closed → nichts tun, Zähler nicht betroffen
+        Catch ex As Exception
+            Try
+                pChannel.Abort()
+            Catch
+                ' Ignore
+            End Try
+        End Try
+    End Sub
     ''' <summary>
     ''' Creates a channel and adds a Faulted-Handler
     ''' </summary>
@@ -44,21 +79,45 @@ Public Class Channel
             Logger.Debug("Creating channel.")
             Dim oChannel = ChannelFactory.CreateChannel()
 
-            AddHandler oChannel.Faulted, Sub() RaiseEvent Reconnect(Me, Nothing)
+            ' Verbindung zählen beim Öffnen
+            AddHandler oChannel.Opened, Sub()
+                                            Dim oCount = Interlocked.Increment(_ActiveConnections)
+                                            Logger.Debug("Channel opened. Active connections: [{0}]", oCount)
+                                        End Sub
 
+            ' Verbindung abziehen beim Schließen oder Fehler
+            AddHandler oChannel.Closed, Sub()
+                                            Dim oCount = Interlocked.Decrement(_ActiveConnections)
+                                            Logger.Debug("Channel closed. Active connections: [{0}]", oCount)
+                                        End Sub
+
+            AddHandler oChannel.Faulted, Sub()
+                                             Dim oCount = Interlocked.Decrement(_ActiveConnections)
+                                             Logger.Warn("Channel faulted. Active connections: [{0}]", oCount)
+                                             RaiseEvent Reconnect(Me, Nothing)
+                                         End Sub
+
+            Logger.Debug("Channel created. State=[{0}]", oChannel.State)
             Return oChannel
         Catch ex As Exception
             Logger.Error(ex)
-            Throw ex
+            Throw
         End Try
     End Function
 
     Private Function GetChannelFactory(pServerAddress As ServerAddressStruct) As ChannelFactory(Of IEDMIServiceChannel)
         Dim oBinding = GetBinding()
         Dim oAddress = New EndpointAddress($"net.tcp://{pServerAddress.Host}:{pServerAddress.Port}/DigitalData/Services/Main")
+        Logger.Debug("Creating ChannelFactory with Binding: SendTimeout=[{0}], ReceiveTimeout=[{1}], MaxConnections=[{2}], MaxBufferSize=[{3}], TransferMode=[{4}]",
+            oBinding.SendTimeout,
+            oBinding.ReceiveTimeout,
+            oBinding.MaxConnections,
+            oBinding.MaxBufferSize,
+            oBinding.TransferMode)
         Dim oFactory = New ChannelFactory(Of IEDMIServiceChannel)(oBinding, oAddress)
         Return oFactory
     End Function
+
 End Class