(Visual FoxPro) SFTP Upload Large File in Parts

See more SFTP Examples

Demonstrates how to split a large file into N parts and then upload each part separately. This technique can be used to potentially avoid limits a SFTP server might impose on upload file size.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loSftp
LOCAL lcHostname
LOCAL lnPort
LOCAL lnSuccess
LOCAL lcHandle
LOCAL lcLocalFilePath
LOCAL loFac
LOCAL lnBlockSize
LOCAL lnNumBlocks
LOCAL loBd
LOCAL i

* This example assumes the Chilkat API to have been previously unlocked.
* See Global Unlock Sample for sample code.

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.SFtp')
loSftp = CreateObject('Chilkat.SFtp')

* Set some timeouts, in milliseconds:
loSftp.ConnectTimeoutMs = 5000
loSftp.IdleTimeoutMs = 10000

* Connect to the SSH server.  
* The standard SSH port = 22
* The hostname may be a hostname or IP address.
lcHostname = "sftp.example.com"
lnPort = 22
lnSuccess = loSftp.Connect(lcHostname,lnPort)
IF (lnSuccess <> 1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

* Authenticate with the SSH server.  Chilkat SFTP supports
* both password-based authenication as well as public-key
* authentication.  This example uses password authenication.
lnSuccess = loSftp.AuthenticatePw("myLogin","myPassword")
IF (lnSuccess <> 1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

* After authenticating, the SFTP subsystem must be initialized:
lnSuccess = loSftp.InitializeSftp()
IF (lnSuccess <> 1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

* Open a remote file for writing on the SSH server.
* If the file already exists, it is overwritten.
* (Specify "createNew" instead of "createTruncate" to
* prevent overwriting existing files.)
lcHandle = loSftp.OpenFile("big.zip","writeOnly","createTruncate")
IF (loSftp.LastMethodSuccess <> 1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    CANCEL
ENDIF

* We're going to upload the local file "qa_data/zips/big.zip" (a relative local path from our current working directory)
* to the SFTP server.
lcLocalFilePath = "qa_data/zips/big.zip"

* Rather than uploading in one shot, we'll read the local file in chunks
* and upload a chunk at a time.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.FileAccess')
loFac = CreateObject('Chilkat.FileAccess')

lnSuccess = loFac.OpenForRead(lcLocalFilePath)
IF (lnSuccess = 0) THEN
    loSftp.CloseHandle(lcHandle)
    ? loFac.LastErrorText
    RELEASE loSftp
    RELEASE loFac
    CANCEL
ENDIF

* If we were to split the local file into 128K chunks, how many chunks (blocks) would
* we have, including the last partial block?
lnBlockSize = 131072
lnNumBlocks = loFac.GetNumBlocks(lnBlockSize)
? "Number of blocks = " + STR(lnNumBlocks)

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.BinData')
loBd = CreateObject('Chilkat.BinData')
i = 0
DO WHILE i < lnNumBlocks
    * Read the Nth block, which gets appended to the bd.  (which means
    * we must clear the contents of bd before the next iteration)
    lnSuccess = loFac.ReadBlockBd(i,lnBlockSize,loBd)
    IF (lnSuccess = 0) THEN
        loSftp.CloseHandle(lcHandle)
        ? loFac.LastErrorText
        RELEASE loSftp
        RELEASE loFac
        RELEASE loBd
        CANCEL
    ENDIF

    * Upload this block to the open remote file.
    lnSuccess = loSftp.WriteFileBd(lcHandle,loBd)
    IF (lnSuccess = 0) THEN
        ? loSftp.LastErrorText
        RELEASE loSftp
        RELEASE loFac
        RELEASE loBd
        CANCEL
    ENDIF

    * Clear the contents for the next iteration.
    loBd.Clear()

    i = i + 1
ENDDO

* Close the local file.
loFac.FileClose()

* -----------------------------------------------------------------------------
* This is important.  You must close the handle on the server.
* Otherwise open handles will accumulate on the server until eventually a limit
* is reached and the server will fail on a call to OpenFile.
* -----------------------------------------------------------------------------

* Close the remote file handle on the server.
lnSuccess = loSftp.CloseHandle(lcHandle)
IF (lnSuccess <> 1) THEN
    ? loSftp.LastErrorText
    RELEASE loSftp
    RELEASE loFac
    RELEASE loBd
    CANCEL
ENDIF

? "Success."

RELEASE loSftp
RELEASE loFac
RELEASE loBd