Price cheker NCR 7802 и Супермаг + : Оборудование

QFX Quick File Transfer Protocol
QFX is a very low overhead protocol that is a much simpler and faster alternative to
FTP for moving files quickly across the network. There is no authentication. The QFX
server permits access to files in and below its default directory; this is the extent of
security.
QFX packets consist of a 4-byte (network order) packet length, a 4-character token, and
possibly data. Packet length includes the 4-byte length field.
Tokens
INFO
File information request/response
SEND
File send request/response
DIFF
File timestamp comparison
ERRR
Error response
INFO exchange
Request
[ length ][ INFO ][ filespec <NUL>]
Response
[ length ][ INFO ][ YYYYMMDDhhmmss size <NUL>]
Four digits for year, two each for month (January is 01), day (01-31), hour (00-23),
minute (00-59), and second (00-59), followed by a single space character, and finally
the size of the file, in bytes.
Response
[ length ][ ERRR ]
Requested file does not exist or request is malformed. Explanatory message is
optional, should be string consisting of number, white space, optional text.
Request
[ length ][ SEND ][ filespec <NUL>]
Response
[ length ][ SEND ][ file data ]
Response
[ length ][ ERRR ]
Requested file does not exist or request is malformed. Explanatory message is
optional, should be string consisting of number, white space, optional text.
Request
[ length ][ DIFF ][ filespec <NUL>][ YYYYMMDDhhmmss<NUL>]
Response
[ length ][ DIFF ][ Bool ]
Bool value is TRUE if the file's date/time are DIFFERENT than the provided
timestamp and FALSE if it is the same.
Response
[ length ][ ERRR ]
Requested file does not exist or request is malformed. Explanatory message is
optional, should be string consisting of number, white space, optional text.

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim server As TcpListener
        server = Nothing
        Try
            ' Set the TcpListener on port 13000.
            Dim port As Int32 = 1283
            Dim localAddr As IPAddress = IPAddress.Parse("192.168.100.11")

            server = New TcpListener(localAddr, port)

            ' Start listening for client requests.
            server.Start()

            ' Buffer for reading data
            Dim bytes(1024) As Byte
            Dim data As String = Nothing

            ' Enter the listening loop.
            While True
                Application.DoEvents()
                l1.Items.Add("Waiting for a connection... ")

                ' Perform a blocking call to accept requests.
                ' You could also user server.AcceptSocket() here.
                Dim client As TcpClient = server.AcceptTcpClient()
                l1.Items.Add("Connected!")

                data = Nothing

                ' Get a stream object for reading and writing
                Dim stream As NetworkStream = client.GetStream()

                Dim i As Int32

                ' Loop to receive all the data sent by the client.
                i = stream.Read(bytes, 0, bytes.Length)
                While (i <> 0)
                    ' Translate data bytes to a ASCII string.
                    data = System.Text.Encoding.ASCII.GetString(bytes, 0, i)
                    l1.Items.Add(data)

                    ' Process the data sent by the client.
                    data = data.ToUpper()
                    Dim msg As Byte() = System.Text.Encoding.ASCII.GetBytes("Book PRICE 22,22")
                    'MsgBox(data)
                    ' Send back a response.
                    stream.Write(msg, 0, msg.Length)
                    l1.Items.Add(data)

                    i = stream.Read(bytes, 0, bytes.Length)

                End While

                ' Shutdown and end connection
                client.Close()
            End While
        Catch ex As SocketException
            l1.Items.Add(ex)
        Finally
            server.Stop()
        End Try

        l1.Items.Add(ControlChars.Cr + "Hit enter to continue....")
    End Sub