Asynchronous Operator | TCP | Serialization

Question

Hello dear Sirs, 

I need your help to make my server and client asynch.

Here is the code 

Dll to serialize : 

Public Class Class1
    <Serializable()>
    Public Class PacketMaker
        Public Property File As Byte()
        Public Property Type_Packet As PacketType
    End Class
    Public Enum PacketType As Integer
        MSG = &H5057
        File = &H5056
    End Enum
End Class

Server : 

Imports System.Net
Imports System.Net.Sockets
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Text
Imports System.Threading
Imports ClassLibrary1.Class1
Public Class Form1
    Public T As TcpListener = New TcpListener(IPAddress.Any, 8080)
    Private client As TcpClient
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        T.Start()
        Task.Run(Sub() D())
    End Sub
    Public Sub D()
        While True
            client = T.AcceptTcpClient()
            Task.Run(Sub() ThreadProc2(client))

           Task.Run(Sub() ThreadProc(client))

        End While
    End Sub

    Private Sub ThreadProc(ByVal obj As Object)
        Dim client = CType(obj, TcpClient)
        Dim B As BinaryFormatter = New BinaryFormatter()
        Dim p As PacketMaker = New PacketMaker()
        p.Type_Packet = PacketType.MSG
        p.File = IO.File.ReadAllBytes("File1.zip")
        B.Serialize(client.GetStream(), p)
    End Sub

    Private Sub ThreadProc2(ByVal obj As Object)
        Dim client = CType(obj, TcpClient)
        Dim B As BinaryFormatter = New BinaryFormatter()
        Dim p As PacketMaker = New PacketMaker()
        p.Type_Packet = PacketType.File
        p.File = IO.File.ReadAllBytes("File2.zip")
        B.Serialize(client.GetStream(), p)

    End Sub

End Class

Client : 

Imports System.Net
Imports System.Net.Sockets
Imports System.Runtime.Serialization.Formatters.Binary
Imports ClassLibrary1.Class1

Public Class Form1
    Private T As TcpClient = New TcpClient()
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim address As String = "192.168.0.15"
        T.Connect(IPAddress.Parse(address), 8080)
        Dim N As NetworkStream = T.GetStream()
        Task.Run(Sub() R(N))
    End Sub
    Public  Sub R(ByVal L As NetworkStream)
        Dim sf As BinaryFormatter = New BinaryFormatter()

        While True

            Dim po As PacketMaker = CType(sf.Deserialize(L), PacketMaker)
    

           IO.File.WriteAllBytes(po.Type_Packet.ToString(), po.File)
        End While
    End Sub


End Class

The server send 2 files and client need to receive them but here nothing is happening. No file is written (MSG & FILE). The only way to avoid problem I have found is to set a synclock here :

  Private Sub ThreadProc(ByVal obj As Object)

        SyncLock T

            Dim client = CType(obj, TcpClient)
        Dim B As BinaryFormatter = New BinaryFormatter()
        Dim p As PacketMaker = New PacketMaker()
        p.Type_Packet = PacketType.MSG
        p.File = IO.File.ReadAllBytes("File1.zip")
            B.Serialize(client.GetStream(), p)
        End SyncLock
    End Sub

    Private Sub ThreadProc2(ByVal obj As Object)

        SyncLock T

            Dim client = CType(obj, TcpClient)
        Dim B As BinaryFormatter = New BinaryFormatter()
        Dim p As PacketMaker = New PacketMaker()
        p.Type_Packet = PacketType.File
        p.File = IO.File.ReadAllBytes("File2.zip")
        B.Serialize(client.GetStream(), p)

        End SyncLock

    End Sub

Answer 1

Hello,

The following are suggestions, incomplete but are solid ideas to use with asynchronous operations. Don't have time to write up a code sample.

Make sure to read the following to get a handle on this type of coding.

Consider using the following where the method need to be marked with Async

Dim client As TcpClient = Await listener.AcceptTcpClientAsync()

I'd use a function e.g.

Public Async Function Run() As Task

And it may be beneficial to have a way to cancel the operation

Public Async Function Run(ByVal cancellationToken As CancellationToken) As Task

Finally consider using a TraceListener to log operations, I have a simple/basic example here.

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Answer 2

So according to : Asynchronous Programming with Async and Await - Visual Basic | Microsoft Docs I can't use TcpClient | Listener Async with binaryformatter and serialization ?

Answer 3

Hi Arsium,

We’re doing research on this issue. It might take some time before we get back to you.

Thank you for your patience

Best Regards,

Xingyu Zhao

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Answer 4

Okay okay no problem hope you will find an idea / solution

Answer 5

Hi Arsium,

Did you consider using asynchronous socket?

Here are two related references you can refer to.

1. Using an Asynchronous Server Socket
2. Using an Asynchronous Client Socket

Besides, here's an example of asynchronous tcp server you may need.

    Private Async Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs)
        Await Task.Run(Sub() RunServerAsync())
    End Sub
    Private Async Sub RunServerAsync()
        Dim listener = New TcpListener(IPAddress.Any, 8080)
        listener.Start()

        Try
            While True
                Await Accept(Await listener.AcceptTcpClientAsync())
            End While
        Finally
            listener.Stop()
        End Try
    End Sub

    Private Async Function Accept(ByVal client As TcpClient) As Task
        Await Task.Yield()
        Try
            Using client
                Using n As NetworkStream = client.GetStream()
                    Dim send_data As Byte()
                    Dim bf As BinaryFormatter = New BinaryFormatter()

                    Using ms = New MemoryStream()
                        bf.Serialize(ms, yourObject)
                        send_data = ms.ToArray()
                    End Using

                    Await n.WriteAsync(send_data, 0, send_data.Length)
                End Using
            End Using

        Catch ex As Exception
            Console.WriteLine(ex.Message)
        End Try
    End Function

Best Regards,

Xingyu Zhao

---

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Answer 6

Okay okay I misspoke my request : is it possible to serialize in parallel (not async) while using binaryformatter and network stream ?

Answer 7

Okay okay I misspoke my request : is it possible to serialize in parallel (not async) while using binaryformatter and network stream ? This causes my problem (not async) I'm beginner sry

Answer 8

Hi Arsium,

>>is it possible to serialize in parallel (not async) while using binaryformatter and network stream ?

Yes, when you send multiple messages using TCP, you need to split the message at the other end in some way.

As you can see in the following code, I save each length of the message to byte array with a fixed length of 4.

Server:

Public Class Form1
    Private port As Integer = 8080
    Private _running As Boolean
    Private listener As TcpListener
    Private connectedTcpClient As TcpClient
    Private _bFormatter As BinaryFormatter = New BinaryFormatter()
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        listener = New TcpListener(IPAddress.Any, port)
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        If Not _running Then
            listener.Start()
            Me._running = True
            Task.Factory.StartNew(Sub()
                                      ListenForClientConnections()
                                  End Sub)
        End If
    End Sub
    Private Sub ListenForClientConnections()
        While Me._running
            Me.connectedTcpClient = listener.AcceptTcpClient()
            Dim networkStream As NetworkStream = Me.connectedTcpClient.GetStream()

            Dim p As PacketMaker = New PacketMaker()
            p.Type_Packet = PacketType.MSG
            p.File = File.ReadAllBytes("D:\test.txt") 'File1.zip
            Dim p2 As PacketMaker = New PacketMaker()
            p2.Type_Packet = PacketType.File
            p2.File = File.ReadAllBytes("D:\test2.txt") 'File2.zip

            SendMessage(_bFormatter, networkStream, p)
            SendMessage(_bFormatter, networkStream, p2)
        End While
    End Sub

    Private Sub SendMessage(ByVal _bFormatter As BinaryFormatter, ByVal networkStream As NetworkStream, ByVal p As PacketMaker)
        Dim header As Byte() = New Byte(3) {}
        Dim send_dataLen As Integer = 0
        Dim send_data As Byte()

        Using ms = New MemoryStream()
            _bFormatter.Serialize(ms, p)
            send_data = ms.ToArray()
            send_dataLen = ms.ToArray().Length
        End Using
        ' Convert the integer type length value to byte array and then send it.
        header = convertToByteArray(header, send_dataLen)
        networkStream.Write(header, 0, header.Length)
        networkStream.Write(send_data, 0, send_data.Length)
    End Sub

    Private Function convertToByteArray(ByVal header As Byte(), ByVal i As Integer) As Byte()
        Dim swi As Switcher = New Switcher()
        swi.intVal = i
        header(0) = swi.b0
        header(1) = swi.b1
        header(2) = swi.b2
        header(3) = swi.b3
        Return header
    End Function
    Public Sub StopListen()
        If Me._running Then
            listener.Stop()
            Me._running = False
        End If
    End Sub
End Class

<StructLayout(LayoutKind.Explicit)>
Structure Switcher
    <FieldOffset(0)>
    Public intVal As Integer
    <FieldOffset(0)>
    Public b0 As Byte
    <FieldOffset(1)>
    Public b1 As Byte
    <FieldOffset(2)>
    Public b2 As Byte
    <FieldOffset(3)>
    Public b3 As Byte
End Structure

Client:

    Private address As String = "your ip address"
    Private port As Integer = 8080
    Private client As TcpClient = New TcpClient()
    Private _bFormatter As BinaryFormatter = New BinaryFormatter()
    Private _running As Boolean
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        client.Connect(IPAddress.Parse(address), port)
        StartListening()
    End Sub
    Public Sub StartListening()
        SyncLock Me

            If Not _running Then
                Me._running = True
                Task.Factory.StartNew(Sub()
                                          ListenForMessage()
                                      End Sub)
            Else
                Me._running = True
                Task.Factory.StartNew(Sub()
                                          ListenForMessage()
                                      End Sub)
            End If
        End SyncLock
    End Sub

    Private Sub ListenForMessage()
        While Me._running
            Dim networkStream As NetworkStream = client.GetStream()
            Dim header As Byte() = New Byte(3) {}
            Dim receive_data As Byte() = New Byte(65534) {}
            Dim packageLen As Integer = 0
            Dim offset As Integer = 0
            Dim bytesRead As Integer = networkStream.Read(receive_data, 0, receive_data.Length)
            Dim count As Integer = 3

            While bytesRead <> 0 AndAlso bytesRead > offset

                Using ms = New MemoryStream()
                    ms.Write(receive_data, offset, 4)
                    header = ms.ToArray()
                    ' Convert length of message byte array to the integer 
                    packageLen = BitConverter.ToInt32(header, 0)
                    ms.Seek(0, SeekOrigin.Begin)
                    ms.Write(receive_data, offset + 4, packageLen)
                    ms.Seek(0, SeekOrigin.Begin)
                    Dim po As PacketMaker = CType(_bFormatter.Deserialize(ms), PacketMaker)
                    File.WriteAllBytes("D:\test" & count & ".txt", po.File)
                    count += 1
                End Using

                offset += packageLen + 4
            End While
        End While
    End Sub

I use two txt files to make the test.

Content in two files.

Result of my test.

Hope it could be helpful.

Best Regards,

Xingyu Zhao

 

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Answer 9

Okay okay thx I will try that !

Answer 10

Hello Sir , 

I've tried your code and nothing is happening with those sent files...I tried with 200MB for first file and 8MB for second and nothing happened. However , it seems working with low size files.