B4X

Socket Receive String Until Specific Byte Value is Received

Demonstrates the Chilkat Socket ReceiveStringUntilByte method. B4X

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 ChilkatSocket
sock.Initialize("sock")

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

Dim useTls As Boolean = False
Dim port As Int = 4242
Dim maxWaitMs As Int = 5000
success = sock.Connect("tcpbin.com", port, useTls, maxWaitMs)
If success = False Then
    Log(sock.LastErrorText)
    Return
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 Int = 0
Dim s1 As String = sock.ReceiveStringUntilByte(lookForByte)
If sock.LastMethodSuccess = False Then
    Log(sock.LastErrorText)
    Return
End If

Log(s1)

Dim s2 As String = sock.ReceiveStringUntilByte(lookForByte)
If sock.LastMethodSuccess = False Then
    Log(sock.LastErrorText)
    Return
End If

Log(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