Visual Basic 6.0

Read Text from a Remote SFTP File (Sequential)

Demonstrates the Chilkat SFtp.ReadFileText method, which reads up to a number of bytes from the current position of an open handle and decodes them to text. The arguments are the handle, the maximum number of bytes, and the charset. This example reads in chunks until end-of-file.

Background: Reading a file in bounded chunks keeps memory use predictable regardless of file size, which is why the loop reads a fixed amount and repeats until Eof. A subtlety worth knowing: the byte limit is applied to the encoded bytes, so a chunk boundary could in principle fall in the middle of a multibyte character — accumulating the pieces and decoding the whole avoids any such issue in practice here since the text is reassembled in a StringBuilder.

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Visual Basic 6.0

Dim success As Long
success = 0

'  Demonstrates the SFtp.ReadFileText method, which reads up to a number of bytes from the current
'  position of an open handle and decodes them to text.  The 1st argument is the handle, the 2nd
'  is the maximum number of bytes, and the 3rd is the charset.

Dim sftp As New ChilkatSFtp

'  Connect, authenticate, and initialize the SFTP subsystem.
Dim port As Long
port = 22
success = sftp.Connect("sftp.example.com",port)
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

'  Normally you would not hard-code the password in source.  You should instead obtain it
'  from an interactive prompt, environment variable, or a secrets vault.
Dim password As String
password = "mySshPassword"

success = sftp.AuthenticatePw("mySshLogin",password)
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

success = sftp.InitializeSftp()
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

'  Open the remote file for reading.
Dim handle As String
handle = sftp.OpenFile("subdir/notes.txt","readOnly","openExisting")
If (sftp.LastMethodSuccess = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

'  Read the file in chunks until end-of-file, accumulating the text.
Dim sbContent As New ChilkatStringBuilder
Dim chunkSize As Long
chunkSize = 4096
Dim reading As Long
reading = 1
Do While reading
    Dim chunk As String
    chunk = sftp.ReadFileText(handle,chunkSize,"utf-8")
    If (sftp.LastReadFailed(handle)) Then
        Debug.Print sftp.LastErrorText
        Exit Sub
    End If

    success = sbContent.Append(chunk)

    '  Stop once the end of the file has been reached.
    reading = Not sftp.Eof(handle)
Loop

success = sftp.CloseHandle(handle)
If (success = 0) Then
    Debug.Print sftp.LastErrorText
    Exit Sub
End If

Debug.Print sbContent.GetAsString()

sftp.Disconnect