Using wininet.dll to retrieve FTP command output

Question

I'm trying to find a simple way of checking user stats via FTP, wininet seems to be the best option. How do I get the output from the command though?

Private Declare Function InternetCloseHandle Lib "wininet.dll" (ByVal HINet As Integer) As Integer
Private Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" (ByVal sAgent As String, ByVal lAccessType As Integer, ByVal sProxyName As String, ByVal sProxyBypass As String, ByVal lFlags As Integer) As Integer
Private Declare Function InternetConnect Lib "wininet.dll" Alias "InternetConnectA" (ByVal hInternetSession As Integer, ByVal sServerName As String, ByVal nServerPort As Integer, ByVal sUsername As String, ByVal sPassword As String, ByVal lService As Integer, ByVal lFlags As Integer, ByVal lContext As Integer) As Integer
Public Declare Function ftpCommand Lib "wininet.dll" Alias "FtpCommandA" (ByVal hConnect As Integer, ByVal fExpectResponse As Boolean, ByVal dwFlags As Integer, ByVal lpszCommand As String, ByRef dwContext As Integer, ByRef phFtpCommand As Integer) As Boolean

Dim INet, INetConn As Integer

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

    INet = InternetOpen("MyFTP", 1, vbNullString, vbNullString, 0)
    INetConn = InternetConnect(INet, "192.168.1.6", 21, "user", "pwd", 1, 0, 0)

    strCommand = "SITE SHOW SERVER 192.168.1.6.21"

    Dim retv As Long
    Dim Test = ftpCommand(INetConn, True, 2, strCommand, 0, retv)
    Debug.Write(Test)

    InternetCloseHandle(INetConn)
    InternetCloseHandle(INet)

End Sub

The output I'm expecting is:

Response:   200- Server IP = "192.168.1.6"
Response:   200- Port = "21"
Response:   200- Start time = "10/02/2010  02:46:57 PM"
Response:   200- Download = "0.000 KB"
Response:   200- Upload = "0.000 KB"
Response:   200- Online Users = "0"
Response:   200-======================================
Response:   200 Site command OK

Thanks.

Answer 1

I think you may find use of InternetGetLastResponseInfo which is a link to the c++ definition

(found this by navigating the WinINet function list) but provides a useful hint

it says:

InternetGetLastResponseInfo Function

Retrieves the last error description or server response on the thread calling this function.

Consider this sample implementation

Private Function GetServerResponse() As String
    Dim lError As Long
    Dim strBuffer As String
    Dim lBufferSize As Long
    Dim retVal As Long
    retVal = InternetGetLastResponseInfo(lError, strBuffer, lBufferSize)
    strBuffer = New String("", lBufferSize + 1)
    retVal = InternetGetLastResponseInfo(lError, strBuffer, lBufferSize)
    GetServerResponse = strBuffer
End Function

Which calls the external function (here for copy paste access)

 Declare Function InternetGetLastResponseInfo Lib "wininet" Alias "InternetGetLastResponseInfoA" (ByRef lpdwError As Long, ByVal lpszBuffer As String, ByRef lpdwBufferLength As Long) As Boolean

twice, once to get the buffer length and again to fill the buffer string then returns the filled buffer