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Get the most updated file

Posted on 2004-10-08
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Last Modified: 2012-06-21
Hi All,

After making a connection to FTP server and setting the FTP direcotry , in my vb application, how can I get the name of the most updated file? There exists many files in that direcotry.

Thanks!

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Question by:cplau
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mladenovicz earned 125 total points
ID: 12260030
Here is the FTP functions sample

Const FTP_TRANSFER_TYPE_UNKNOWN = &H0
Const FTP_TRANSFER_TYPE_ASCII = &H1
Const FTP_TRANSFER_TYPE_BINARY = &H2
Const INTERNET_DEFAULT_FTP_PORT = 21               ' default for FTP servers
Const INTERNET_SERVICE_FTP = 1
Const INTERNET_FLAG_PASSIVE = &H8000000            ' used for FTP connections
Const INTERNET_OPEN_TYPE_PRECONFIG = 0                    ' use registry configuration
Const INTERNET_OPEN_TYPE_DIRECT = 1                        ' direct to net
Const INTERNET_OPEN_TYPE_PROXY = 3                         ' via named proxy
Const INTERNET_OPEN_TYPE_PRECONFIG_WITH_NO_AUTOPROXY = 4   ' prevent using java/script/INS
Const MAX_PATH = 260
Private Type FILETIME
    dwLowDateTime As Long
    dwHighDateTime As Long
End Type
Private Type WIN32_FIND_DATA
    dwFileAttributes As Long
    ftCreationTime As FILETIME
    ftLastAccessTime As FILETIME
    ftLastWriteTime As FILETIME
    nFileSizeHigh As Long
    nFileSizeLow As Long
    dwReserved0 As Long
    dwReserved1 As Long
    cFileName As String * MAX_PATH
    cAlternate As String * 14
End Type
Private Declare Function InternetCloseHandle Lib "wininet" (ByRef hInet As Long) As Long
Private Declare Function InternetConnect Lib "wininet.dll" Alias "InternetConnectA" (ByVal hInternetSession As Long, ByVal sServerName As String, ByVal nServerPort As Integer, ByVal sUserName As String, ByVal sPassword As String, ByVal lService As Long, ByVal lFlags As Long, ByVal lContext As Long) As Long
Private Declare Function InternetOpen Lib "wininet.dll" Alias "InternetOpenA" (ByVal sAgent As String, ByVal lAccessType As Long, ByVal sProxyName As String, ByVal sProxyBypass As String, ByVal lFlags As Long) As Long
Private Declare Function FtpSetCurrentDirectory Lib "wininet.dll" Alias "FtpSetCurrentDirectoryA" (ByVal hFtpSession As Long, ByVal lpszDirectory As String) As Boolean
Private Declare Function FtpGetCurrentDirectory Lib "wininet.dll" Alias "FtpGetCurrentDirectoryA" (ByVal hFtpSession As Long, ByVal lpszCurrentDirectory As String, lpdwCurrentDirectory As Long) As Long
Private Declare Function FtpCreateDirectory Lib "wininet.dll" Alias "FtpCreateDirectoryA" (ByVal hFtpSession As Long, ByVal lpszDirectory As String) As Boolean
Private Declare Function FtpRemoveDirectory Lib "wininet.dll" Alias "FtpRemoveDirectoryA" (ByVal hFtpSession As Long, ByVal lpszDirectory As String) As Boolean
Private Declare Function FtpDeleteFile Lib "wininet.dll" Alias "FtpDeleteFileA" (ByVal hFtpSession As Long, ByVal lpszFileName As String) As Boolean
Private Declare Function FtpRenameFile Lib "wininet.dll" Alias "FtpRenameFileA" (ByVal hFtpSession As Long, ByVal lpszExisting As String, ByVal lpszNew As String) As Boolean
Private Declare Function FtpGetFile Lib "wininet.dll" Alias "FtpGetFileA" (ByVal hConnect As Long, ByVal lpszRemoteFile As String, ByVal lpszNewFile As String, ByVal fFailIfExists As Long, ByVal dwFlagsAndAttributes As Long, ByVal dwFlags As Long, ByRef dwContext As Long) As Boolean
Private Declare Function FtpPutFile Lib "wininet.dll" Alias "FtpPutFileA" (ByVal hConnect As Long, ByVal lpszLocalFile As String, ByVal lpszNewRemoteFile As String, ByVal dwFlags As Long, ByVal dwContext As Long) As Boolean
Private Declare Function InternetGetLastResponseInfo Lib "wininet.dll" Alias "InternetGetLastResponseInfoA" (lpdwError As Long, ByVal lpszBuffer As String, lpdwBufferLength As Long) As Boolean
Private Declare Function FtpFindFirstFile Lib "wininet.dll" Alias "FtpFindFirstFileA" (ByVal hFtpSession As Long, ByVal lpszSearchFile As String, lpFindFileData As WIN32_FIND_DATA, ByVal dwFlags As Long, ByVal dwContent As Long) As Long
Private Declare Function InternetFindNextFile Lib "wininet.dll" Alias "InternetFindNextFileA" (ByVal hFind As Long, lpvFindData As WIN32_FIND_DATA) As Long
Const PassiveConnection As Boolean = True
Private Sub Form_Load()
    'KPD-Team 2000
    'URL: http://www.allapi.net
    'E-Mail: KPDTeam@allapi.net
    Dim hConnection As Long, hOpen As Long, sOrgPath  As String
    'open an internet connection
    hOpen = InternetOpen("API-Guide sample program", INTERNET_OPEN_TYPE_PRECONFIG, vbNullString, vbNullString, 0)
    'connect to the FTP server
    hConnection = InternetConnect(hOpen, "your ftp server", INTERNET_DEFAULT_FTP_PORT, "your login", "your password", INTERNET_SERVICE_FTP, IIf(PassiveConnection, INTERNET_FLAG_PASSIVE, 0), 0)
    'create a buffer to store the original directory
    sOrgPath = String(MAX_PATH, 0)
    'get the directory
    FtpGetCurrentDirectory hConnection, sOrgPath, Len(sOrgPath)
    'create a new directory 'testing'
    FtpCreateDirectory hConnection, "testing"
    'set the current directory to 'root/testing'
    FtpSetCurrentDirectory hConnection, "testing"
    'upload the file 'test.htm'
    FtpPutFile hConnection, "C:\test.htm", "test.htm", FTP_TRANSFER_TYPE_UNKNOWN, 0
    'rename 'test.htm' to 'apiguide.htm'
    FtpRenameFile hConnection, "test.htm", "apiguide.htm"
    'enumerate the file list from the current directory ('root/testing')
    EnumFiles hConnection
    'retrieve the file from the FTP server
    FtpGetFile hConnection, "apiguide.htm", "c:\apiguide.htm", False, 0, FTP_TRANSFER_TYPE_UNKNOWN, 0
    'delete the file from the FTP server
    FtpDeleteFile hConnection, "apiguide.htm"
    'set the current directory back to the root
    FtpSetCurrentDirectory hConnection, sOrgPath
    'remove the direcrtory 'testing'
    FtpRemoveDirectory hConnection, "testing"
    'close the FTP connection
    InternetCloseHandle hConnection
    'close the internet connection
    InternetCloseHandle hOpen
End Sub
Public Sub EnumFiles(hConnection As Long)
    Dim pData As WIN32_FIND_DATA, hFind As Long, lRet As Long
    'set the graphics mode to persistent
    Me.AutoRedraw = True
    'create a buffer
    pData.cFileName = String(MAX_PATH, 0)
    'find the first file
    hFind = FtpFindFirstFile(hConnection, "*.*", pData, 0, 0)
    'if there's no file, then exit sub
    If hFind = 0 Then Exit Sub
    'show the filename
    Me.Print Left(pData.cFileName, InStr(1, pData.cFileName, String(1, 0), vbBinaryCompare) - 1)
    Do
        'create a buffer
        pData.cFileName = String(MAX_PATH, 0)
        'find the next file
        lRet = InternetFindNextFile(hFind, pData)
        'if there's no next file, exit do
        If lRet = 0 Then Exit Do
        'show the filename
        Me.Print Left(pData.cFileName, InStr(1, pData.cFileName, String(1, 0), vbBinaryCompare) - 1)
    Loop
    'close the search handle
    InternetCloseHandle hFind
End Sub
Sub ShowError()
    Dim lErr As Long, sErr As String, lenBuf As Long
    'get the required buffer size
    InternetGetLastResponseInfo lErr, sErr, lenBuf
    'create a buffer
    sErr = String(lenBuf, 0)
    'retrieve the last respons info
    InternetGetLastResponseInfo lErr, sErr, lenBuf
    'show the last response info
    MsgBox "Error " + CStr(lErr) + ": " + sErr, vbOKOnly + vbCritical
End Sub

Enumfiles  method will be interesting for you. WIN32_FIND_DATA UDT have file time "properties" u can use to determine the newest file
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LVL 8

Expert Comment

by:mladenovicz
ID: 12260048
you can use FileTimeToLocalFileTime API to convert FILETIME to system time

Private Type SYSTEMTIME
wYear As Integer
wMonth As Integer
wDayOfWeek As Integer
wDay As Integer
wHour As Integer
wMinute As Integer
wSecond As Integer
wMilliseconds As Integer
End Type

Private Declare Function FileTimeToLocalFileTime Lib "kernel32" (lpFileTime As FILETIME, lpLocalFileTime As FILETIME) As Long
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Author Comment

by:cplau
ID: 12260902
Dear mladenovicz,

Beside checking all files at that directory, how about if sub-direcotries exists?

Can I know which sub-direcotires exists? Then change to that direcotry and search it again. Thank!
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Author Comment

by:cplau
ID: 12260946
Dear mladenovicz,

For your suggested method, is it very time-consuming if many files exists in their directory? e.g. 500 files.

Is there a major difference between getting all 500 files once without checking and get each one by one with checking tis modified time?
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Expert Comment

by:mladenovicz
ID: 12261000
FtpFindFirstFile will pickup subfolders too. You should check dwFileAttributes As Long from WIN32_FIND_DATA  to check if it is subfolder, after that you should call recursively your function that looks for file

You should loop through files with FtpFindFirstFile (see EnumFiles method) and find the newest file. I think that you don't have to download all files.
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LVL 8

Expert Comment

by:mladenovicz
ID: 12563696
I think that my answer is correct, but let's hear cplau 's opinion
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