#include <GUIConstantsEx.au3>
#include <MsgBoxConstants.au3>

; Start First clicking on "1. Server"
; Then start a second instance of the script selecting "2. Client"

Example()

Func Example()
        TCPStartup() ; Start the TCP service.

        ; Register OnAutoItExit to be called when the script is closed.
        OnAutoItExitRegister("OnAutoItExit")

        ; Assign Local variables the loopback IP Address and the Port.
        Local $sIPAddress = "127.0.0.1" ; This IP Address only works for testing on your own computer.
        Local $iPort = 65432 ; Port used for the connection.

        #Region GUI
        Local $sTitle = "TCP Start"
        Local $hGUI = GUICreate($sTitle, 250, 70)

        Local $idBtnServer = GUICtrlCreateButton("1. Server", 65, 10, 130, 22)

        Local $idBtnClient = GUICtrlCreateButton("2. Client", 65, 40, 130, 22)

        GUISetState(@SW_SHOW, $hGUI)

        While 1
                Switch GUIGetMsg()
                        Case $GUI_EVENT_CLOSE
                                ExitLoop
                        Case $idBtnServer
                                WinSetTitle($sTitle, "", "TCP Server started")
                                GUICtrlSetState($idBtnClient, $GUI_HIDE)
                                GUICtrlSetState($idBtnServer, $GUI_DISABLE)
                                If Not MyTCP_Server($sIPAddress, $iPort) Then ExitLoop
                        Case $idBtnClient
                                WinSetTitle($sTitle, "", "TCP Client started")
                                GUICtrlSetState($idBtnServer, $GUI_HIDE)
                                GUICtrlSetState($idBtnClient, $GUI_DISABLE)
                                If Not MyTCP_Client($sIPAddress, $iPort) Then ExitLoop
                EndSwitch

                Sleep(10)
        WEnd

        #EndRegion GUI
EndFunc   ;==>Example

Func MyTCP_Client($sIPAddress, $iPort)
        ; Assign a Local variable the socket and connect to a listening socket with the IP Address and Port specified.
        Local $iSocket = TCPConnect($sIPAddress, $iPort)
        Local $iError = 0

        ; If an error occurred display the error code and return False.
        If @error Then
                ; The server is probably offline/port is not opened on the server.
                $iError = @error
                MsgBox(($MB_ICONERROR + $MB_SYSTEMMODAL), "", "Client:" & @CRLF & "Could not connect, Error code: " & $iError)
                Return False
        EndIf

        ; Send the string "tata" to the server.
        TCPSend($iSocket, "tata")

        ; If an error occurred display the error code and return False.
        If @error Then
                $iError = @error
                MsgBox(($MB_ICONERROR + $MB_SYSTEMMODAL), "", "Client:" & @CRLF & "Could not send the data, Error code: " & $iError)
                Return False
        EndIf

        ; Close the socket.
        TCPCloseSocket($iSocket)
EndFunc   ;==>MyTCP_Client

Func MyTCP_Server($sIPAddress, $iPort)
        ; Assign a Local variable the socket and bind to the IP Address and Port specified with a maximum of 100 pending connexions.
        Local $iListenSocket = TCPListen($sIPAddress, $iPort, 100)
        Local $iError = 0

        If @error Then
                ; Someone is probably already listening on this IP Address and Port (script already running?).
                $iError = @error
                MsgBox(($MB_ICONERROR + $MB_SYSTEMMODAL), "", "Server:" & @CRLF & "Could not listen, Error code: " & $iError)
                Return False
        EndIf

        ; Assign a Local variable to be used by the Client socket.
        Local $iSocket = 0

        Do ; Wait for someone to connect (Unlimited).
                ; Accept incomming connexions if present (Socket to close when finished; one socket per client).
                $iSocket = TCPAccept($iListenSocket)

                ; If an error occurred display the error code and return False.
                If @error Then
                        $iError = @error
                        MsgBox(($MB_ICONERROR + $MB_SYSTEMMODAL), "", "Server:" & @CRLF & "Could not accept the incoming connection, Error code: " & $iError)
                        Return False
                EndIf

                If GUIGetMsg() = $GUI_EVENT_CLOSE Then Return False
        Until $iSocket <> -1 ;if different from -1 a client is connected.

        ; Close the Listening socket to allow afterward binds.
        TCPCloseSocket($iListenSocket)

        ; Assign a Local variable the data received.
        Local $sReceived = TCPRecv($iSocket, 4) ;we're waiting for the string "tata" OR "toto" (example script TCPRecv): 4 bytes length.

        ; Notes: If you don't know how much length will be the data,
        ; use e.g: 2048 for maxlen parameter and call the function until the it returns nothing/error.

        ; Display the string received.
        MsgBox($MB_SYSTEMMODAL, "", "Server:" & @CRLF & "Received: " & $sReceived)

        ; Close the socket.
        TCPCloseSocket($iSocket)
EndFunc   ;==>MyTCP_Server

Func OnAutoItExit()
        TCPShutdown() ; Close the TCP service.
EndFunc   ;==>OnAutoItExit