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Pilz.Networking/UDPManager.vb

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+Imports System.IO
+Imports System.Net
+Imports System.Net.NetworkInformation
+Imports System.Net.Sockets
+Imports System.Threading
+Imports Newtonsoft.Json.Linq
+
+Public Class UDPManager
+    Inherits ConnectionManagerBase
+
+    Private ReadOnly client As UdpClient
+    Private listenTask As Task = Nothing
+    Private ReadOnly cancelTokenSource As New CancellationTokenSource
+    Private ReadOnly cancelToken As CancellationToken = cancelTokenSource.Token
+
+    Public Sub New(port As Integer)
+        MyBase.New(port)
+        client = New UdpClient(port)
+    End Sub
+
+    Protected Overrides Sub Finalize()
+        MyBase.Finalize()
+        client.Client.Shutdown(SocketShutdown.Both)
+        client.Close()
+    End Sub
+
+    Public Overrides Sub Start()
+        If Not IsListening Then
+            StartInternal()
+        End If
+    End Sub
+
+    Private Sub StartInternal()
+        IsListening = True
+        listenTask = Task.Run(
+            Sub()
+                Try
+                    RetriveAnyData(cancelToken)
+                Catch ex As Exception
+                    IsListening = False
+                End Try
+            End Sub)
+    End Sub
+
+    ''' <summary>
+    ''' Stop listening on given port.
+    ''' </summary>
+    Public Overrides Sub [Stop]()
+        If IsListening Then
+            IsListening = False
+            cancelTokenSource.Cancel()
+            listenTask.Wait()
+        End If
+    End Sub
+
+    Private Sub RetriveAnyData(ct As CancellationToken)
+        Dim doExit = Sub() ct.ThrowIfCancellationRequested()
+        Dim receiveTask As Task(Of UdpReceiveResult) = client.ReceiveAsync()
+
+        'Wait for the data and cancel if requested
+        receiveTask.Wait(ct)
+
+        Dim buf As Byte() = receiveTask.Result.Buffer
+        Dim ip As String = receiveTask.Result.RemoteEndPoint.Address.ToString
+        Dim cmd As String = String.Empty
+        Dim content As Object = Nothing
+
+        doExit()
+
+        Try
+            Dim res = DecodeFromBytes(buf)
+            cmd = res.cmd
+            content = res.content
+        Catch ex As Exception
+        End Try
+
+        RaiseRetriveData(ip, cmd, content)
+
+        doExit()
+        StartInternal()
+    End Sub
+
+    Public Overrides Sub Send(empfängerIP As String, cmd As String, content As Object)
+        Dim ep As New IPEndPoint(GetIPFromHost(empfängerIP).MapToIPv4, Port)
+        Dim udp As New UdpClient
+        Dim buf As Byte() = EncodeToBytes(cmd, content)
+
+        udp.Connect(ep)
+        udp.Send(buf, buf.Length)
+        udp.Client.Shutdown(SocketShutdown.Both)
+        udp.Close()
+    End Sub
+
+End Class