PowerBuilder

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. PowerBuilder

integer li_rc
long li_Success
oleobject loo_Sftp
string ls_Hostname
long li_Port
string ls_Handle
string ls_LocalFilePath
oleobject loo_Fac
long li_BlockSize
long li_NumBlocks
oleobject loo_Bd
long i

li_Success = 0

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

loo_Sftp = create oleobject
li_rc = loo_Sftp.ConnectToNewObject("Chilkat.SFtp")
if li_rc < 0 then
    destroy loo_Sftp
    MessageBox("Error","Connecting to COM object failed")
    return
end if

//  Set some timeouts, in milliseconds:
loo_Sftp.ConnectTimeoutMs = 5000
loo_Sftp.IdleTimeoutMs = 10000

//  Connect to the SSH server.  
//  The standard SSH port = 22
//  The hostname may be a hostname or IP address.
ls_Hostname = "sftp.example.com"
li_Port = 22
li_Success = loo_Sftp.Connect(ls_Hostname,li_Port)
if li_Success <> 1 then
    Write-Debug loo_Sftp.LastErrorText
    destroy loo_Sftp
    return
end if

//  Authenticate with the SSH server.  Chilkat SFTP supports
//  both password-based authenication as well as public-key
//  authentication.  This example uses password authenication.
li_Success = loo_Sftp.AuthenticatePw("myLogin","myPassword")
if li_Success <> 1 then
    Write-Debug loo_Sftp.LastErrorText
    destroy loo_Sftp
    return
end if

//  After authenticating, the SFTP subsystem must be initialized:
li_Success = loo_Sftp.InitializeSftp()
if li_Success <> 1 then
    Write-Debug loo_Sftp.LastErrorText
    destroy loo_Sftp
    return
end if

//  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.)
ls_Handle = loo_Sftp.OpenFile("big.zip","writeOnly","createTruncate")
if loo_Sftp.LastMethodSuccess <> 1 then
    Write-Debug loo_Sftp.LastErrorText
    destroy loo_Sftp
    return
end if

//  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.
ls_LocalFilePath = "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.
loo_Fac = create oleobject
li_rc = loo_Fac.ConnectToNewObject("Chilkat.FileAccess")

li_Success = loo_Fac.OpenForRead(ls_LocalFilePath)
if li_Success = 0 then
    loo_Sftp.CloseHandle(ls_Handle)
    Write-Debug loo_Fac.LastErrorText
    destroy loo_Sftp
    destroy loo_Fac
    return
end if

//  If we were to split the local file into 128K chunks, how many chunks (blocks) would
//  we have, including the last partial block?
li_BlockSize = 131072
li_NumBlocks = loo_Fac.GetNumBlocks(li_BlockSize)
Write-Debug "Number of blocks = " + string(li_NumBlocks)

loo_Bd = create oleobject
li_rc = loo_Bd.ConnectToNewObject("Chilkat.BinData")

i = 0
do while i < li_NumBlocks
    //  Read the Nth block, which gets appended to the bd.  (which means
    //  we must clear the contents of bd before the next iteration)
    li_Success = loo_Fac.ReadBlockBd(i,li_BlockSize,loo_Bd)
    if li_Success = 0 then
        loo_Sftp.CloseHandle(ls_Handle)
        Write-Debug loo_Fac.LastErrorText
        destroy loo_Sftp
        destroy loo_Fac
        destroy loo_Bd
        return
    end if

    //  Upload this block to the open remote file.
    li_Success = loo_Sftp.WriteFileBd(ls_Handle,loo_Bd)
    if li_Success = 0 then
        Write-Debug loo_Sftp.LastErrorText
        destroy loo_Sftp
        destroy loo_Fac
        destroy loo_Bd
        return
    end if

    //  Clear the contents for the next iteration.
    loo_Bd.Clear()

    i = i + 1
loop

//  Close the local file.
loo_Fac.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.
li_Success = loo_Sftp.CloseHandle(ls_Handle)
if li_Success <> 1 then
    Write-Debug loo_Sftp.LastErrorText
    destroy loo_Sftp
    destroy loo_Fac
    destroy loo_Bd
    return
end if

Write-Debug "Success."


destroy loo_Sftp
destroy loo_Fac
destroy loo_Bd