Read WebSocket client data to the server vb.net - websocket

Question

Good afternoon. I clarify that I don't know much about WebSockets, but I'm learning about it. I am trying to make a connection between vb.net (server) and browser (client) using WebSocket. Searching on the internet I could make this work (Websocket Server VB.NET - Data Frame) Currently I can send a message from vb.net to the browser, but I have not known how to read the messages that the client sends to the server .. I found a code about it, but I do not understand well how it could be implemented to my code (WebSocket Server, client -> server frame mask)
CLIENT
function connect(host) {
var ws = new WebSocket(host);
ws.onopen = function () {
console('connected');
//ws.send("test");
};
ws.onmessage = function (evt) {
console('reveived data:'+evt.data);
};
ws.onclose = function () {
console('socket closed');
};
SERVER
Imports System.Net.Sockets
Imports System.Threading
Imports System.Net
Public Class Form1
Dim serverTcp As TcpListener
Dim serverThread As Thread
Dim host_ As String = ""
Dim curSocket As Socket
Sub Main()
'' Start server
serverThread = New Thread(AddressOf serverProc)
serverThread.Start()
End Sub
Private Sub serverProc()
Try
'' Listen to port 5665
serverTcp = New TcpListener(System.Net.IPAddress.Parse(host_), 5665)
serverTcp.Start()
Console.WriteLine("Listen to port 5665 ...")
'' Accept any connection
While (True)
curSocket = serverTcp.AcceptSocket()
Dim thread As New Thread(AddressOf clientProc)
thread.Start(curSocket)
End While
Catch ex As Exception
End Try
End Sub
Private Sub clientProc(ByVal sck As Socket)
Try
Dim netStream As New NetworkStream(sck)
Dim netReader As New IO.StreamReader(netStream)
Dim netWriter As New IO.StreamWriter(netStream)
Dim key As String = ""
Console.WriteLine("Accept new connection ...")
'' Reading handshake message
While (True)
Dim line As String = netReader.ReadLine()
If line.Length = 0 Then
Exit While
End If
If (line.StartsWith("Sec-WebSocket-Key: ")) Then
key = line.Split(":")(1).Trim()
End If
Console.WriteLine("Data: " & line)
End While
'' Calculate accept-key
key += "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
key = getSHA1Hash(key)
'' Response handshake message
Dim response As String
response = "HTTP/1.1 101 Switching Protocols" & vbCrLf
response &= "Upgrade: websocket" & vbCrLf
response &= "Connection: Upgrade" & vbCrLf
response &= "Sec-WebSocket-Accept: " & key & vbCrLf & vbCrLf
netWriter.Write(response)
netWriter.Flush()
'' Sending message
SendMessage(sck, "SEND.. VB.NET")
Catch ex As Exception
End Try
End Sub
Sub Msg(t As String)
Console.WriteLine(t)
End Sub
Function getSHA1Hash(ByVal strToHash As String) As String
Dim sha1Obj As New System.Security.Cryptography.SHA1CryptoServiceProvider
Dim bytesToHash() As Byte = System.Text.Encoding.ASCII.GetBytes(strToHash)
Dim result As String
bytesToHash = sha1Obj.ComputeHash(bytesToHash)
result = Convert.ToBase64String(bytesToHash)
Return result
End Function
Sub SendMessage(sck As Socket, message As String)
Dim rawData = System.Text.Encoding.UTF8.GetBytes(message)
Dim frameCount = 0
Dim frame(10) As Byte
frame(0) = CByte(129)
If rawData.Length <= 125 Then
frame(1) = CByte(rawData.Length)
frameCount = 2
ElseIf rawData.Length >= 126 AndAlso rawData.Length <= 65535 Then
frame(1) = CByte(126)
Dim len = CByte(rawData.Length)
frame(2) = CByte(((len >> 8) & CByte(255)))
frame(3) = CByte((len & CByte(255)))
frameCount = 4
Else
frame(1) = CByte(127)
Dim len = CByte(rawData.Length)
frame(2) = CByte(((len >> 56) & CByte(255)))
frame(3) = CByte(((len >> 48) & CByte(255)))
frame(4) = CByte(((len >> 40) & CByte(255)))
frame(5) = CByte(((len >> 32) & CByte(255)))
frame(6) = CByte(((len >> 24) & CByte(255)))
frame(7) = CByte(((len >> 16) & CByte(255)))
frame(8) = CByte(((len >> 8) & CByte(255)))
frame(9) = CByte((len & CByte(255)))
frameCount = 10
End If
Dim bLength = frameCount + rawData.Length
Console.WriteLine(frameCount)
Console.WriteLine(rawData.Length)
Dim reply(bLength + 1) As Byte
Dim bLim = 0
For i = 0 To frameCount - 1
Console.WriteLine(bLim)
reply(bLim) = frame(i)
bLim += 1
Next
For i = 0 To rawData.Length - 1
Console.WriteLine(bLim)
reply(bLim) = rawData(i)
bLim += 1
Next
sck.Send(reply)
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
host_ = Dns.GetHostEntry(Dns.GetHostName()).AddressList _
.Where(Function(a As IPAddress) Not a.IsIPv6LinkLocal AndAlso Not a.IsIPv6Multicast AndAlso Not a.IsIPv6SiteLocal) _
.Last() _
.ToString()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Main()
End Sub
Private Sub btnEnviarMensaje_Click(sender As Object, e As EventArgs) Handles btnEnviarMensaje.Click
SendMessage(curSocket, txtMensaje.Text)
End Sub
End Class

Answer 1

it is simple if you want implement this in your vb.net project
you have to put this code anywhere in your project to calling
you also can use it as a "clientProc" private sub or you also
can insert this code in button1 object if you will click on button
after handshake it will give you return web browser websocket client message
Dim netStream As New NetworkStream(curSocket)
Dim bytesArray(1024) As [Byte]
Dim byteslen As Int32
byteslen = netStream.Read(bytesArray, 0, bytesArray.Length)
If bytesArray.Length > 1 Then
Msg("---------------------------------------------------")
Msg("data type: " & bytesArray(0))
Dim secondByte As Byte = bytesArray(1)
Dim theLength As UInteger = secondByte And 127
Dim indexFirstMask As Integer = 2
If theLength = 126 Then
indexFirstMask = 4
ElseIf theLength = 127 Then
indexFirstMask = 10
End If
Msg("indexFirstMask: " & indexFirstMask)
Dim masks As New List(Of Byte)
Dim x As Integer = indexFirstMask
While (x < indexFirstMask + 4)
masks.Add(bytesArray(x))
x += 1
End While
Dim indexFirstDataByte = indexFirstMask + 4
Dim decoded(byteslen - indexFirstDataByte) As Byte
Dim i As Integer = 0, j As Integer = 0
For i = indexFirstDataByte To byteslen Step 1
Dim mask As Byte = masks(j Mod 4)
Dim encodedByte As Byte = bytesArray(i)
decoded(j) = (encodedByte Xor mask)
j += 1
Next
Console.WriteLine("FROM CLIENT: '" & System.Text.Encoding.UTF8.GetString(decoded) & "'")
'Console.WriteLine("temp " + decoded.ToString)
SendMessage(curSocket, "CONNECTION_OK")
End If