VB.NET

Socket Receive String Until Specific Byte Value is Received

Demonstrates the Chilkat Socket ReceiveStringUntilByte method. VB.NET

Dim success As Boolean = False

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim sock As New Chilkat.Socket

' --------------------------------------------------------------------
' This example uses the public TCP echo service at https://tcpbin.com/
' --------------------------------------------------------------------

Dim useTls As Boolean = False
Dim port As Integer = 4242
Dim maxWaitMs As Integer = 5000
success = sock.Connect("tcpbin.com",port,useTls,maxWaitMs)
If (success = False) Then
    Debug.WriteLine(sock.LastErrorText)
    Exit Sub
End If


' Wait a max of 2 seconds for a response..
sock.MaxReadIdleMs = 2000

' Send some strings, each terminated by a 0 byte.
sock.SendString("This is the 1st string")
sock.SendByte(0)
sock.SendString("This is string number 2")
sock.SendByte(0)

' The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
sock.SendByte(10)

' Now let's receive what is echoed back....
' Receive each string and the NULL byte.
' The call to ReceiveStringUntilByte will receive incoming data until the lookForByte is encountered.
' The lookForByte is receive and discarded (it is not returned in the string)
Dim lookForByte As Integer = 0
Dim s1 As String = sock.ReceiveStringUntilByte(lookForByte)
If (sock.LastMethodSuccess = False) Then
    Debug.WriteLine(sock.LastErrorText)
    Exit Sub
End If

Debug.WriteLine(s1)

Dim s2 As String = sock.ReceiveStringUntilByte(lookForByte)
If (sock.LastMethodSuccess = False) Then
    Debug.WriteLine(sock.LastErrorText)
    Exit Sub
End If

Debug.WriteLine(s2)

' The echo server will also echo back the final LF
sock.ReceiveByte(True)
maxWaitMs = 100
sock.Close(100)

' Output:
' This is the 1st string
' This is string number 2