Upload local file and append it to existing file

[Shardik]

The following code uses the WinAPI to upload a local file to an FTP server. If the file doesn't exist on the server, it is created. But an already existing file doesn't get overwritten. It remains intact and the uploaded file is appended to the end of the server file. This is especially useful in a datacenter with a mainframe where new data are transferred to the server at the end of every work day and collected there until the end of the week when the final processing on the mainframe takes place.

Code: Select all

; ----- Upload local file and append it to existing file on FTP-Server

; Please change to your UserID/Password etc.:
; -------------------------------------------------
#ClientFilename = "YourClientPathAndFilename.Txt"
#FTPServerIP = "YourServerNameOrIP"
#Password = "YourPassword"
#ServerFilename = "YourServerPathAndFilename.Txt"
#UserID = "YourUserID"
; -------------------------------------------------

#FileBufferSize = 1024
#FTP_TRANSFER_TYPE_ASCII = 1
#INTERNET_DEFAULT_FTP_PORT = 21
#INTERNET_SERVICE_FTP = 1

ErrorBuffer.S
ErrorBufferSize.L
ErrorCode.L
FTPConnectHandle.L
FTPFileHandle.L
FTPOpenHandle.L
NumBytesRead.L
NumBytesWritten.L

FTPOpenHandle = InternetOpen_("FTP", 1, "", "", 0)

If FTPOpenHandle = 0
  MessageRequester("Error", "Initialisation of FTP connection failed!", #MB_ICONERROR)
  End
EndIf

FTPConnectHandle = InternetConnect_(FTPOpenHandle, #FTPServerIP, #INTERNET_DEFAULT_FTP_PORT, #UserID, #Password, #INTERNET_SERVICE_FTP, 0, 0)

If FTPConnectHandle = 0
  MessageRequester("Error", "Connection to FTP Server failed!", #MB_ICONERROR)
Else
  If FtpCommand_(FTPConnectHandle, #True, #FTP_TRANSFER_TYPE_ASCII, "APPE " + #ServerFilename + #CRLF$, 0, @FTPFileHandle) = #False
    ErrorCode = GetLastError_()

    If ErrorCode = 0
      MessageRequester("Error", "The Windows call GetLastError() didn't return an error code!", #MB_ICONERROR)
    Else
      InternetGetLastResponseInfo_(@ErrorCode, 0, @ErrorBufferSize)

      If ErrorBufferSize > 0
        ErrorBuffer = Space(ErrorBufferSize)
        InternetGetLastResponseInfo_(@ErrorCode, @ErrorBuffer, @ErrorBufferSize)
        MessageRequester("Error", RemoveString(ErrorBuffer, #CRLF$))
      EndIf
    EndIf
  Else
    If FTPFileHandle = 0
      MessageRequester("Error", "The FTP Server didn't provide a data connection port!", #MB_ICONERROR)
    Else
      If ReadFile(1, #ClientFilename) = #False
        MessageRequester("Error", "Opening of local file '" + #ClientFilename + "' failed!", #MB_ICONERROR)
      Else
        *FileBuffer = AllocateMemory(#FileBufferSize)

        While Eof(1) = 0
          NumBytesRead = ReadData(1, *FileBuffer, #FileBufferSize)
          If InternetWriteFile_(FTPFileHandle, *FileBuffer, NumBytesRead, @NumBytesWritten) = #False
            MessageRequester("Error", "Upload of local file to FTP Server failed!", #MB_ICONERROR)
            AppendFailed = #True
            Break
          EndIf
        Wend

        If AppendFailed <> #True
          MessageRequester("Info", "The local file '" + #ClientFilename + "' was successfully appended" + #CR$ + "to the server file " + #ServerFilename, #MB_ICONINFORMATION)
        EndIf
      EndIf
    EndIf
  EndIf
EndIf

If InternetCloseHandle_(FTPOpenHandle) = #False
  MessageRequester("Error", "Closing of FTP connection failed!", #MB_ICONERROR)
EndIf

The code uses the powerful and not very well known WinInet function FTPCommand() with which you can send FTP commands to the FTP server which are not implemented in WinInet. For a better understanding of the FTPCommand() function and its powerful possibilities take a look at the following background information for Visual BASIC applications:

http://www.vbip.com/wininet/wininet-ftp-command-01.asp