B4X

Read Text at a String Offset from a Remote SFTP File

Demonstrates the Chilkat SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte offset as a decimal string. The arguments are the handle, the offset string, the maximum number of bytes, and the charset.

Background: The string-offset read exists for the same reason as its write counterpart: it lets code in languages without convenient 64-bit integers still address positions in very large files by supplying the offset as text. Functionally it is identical to the int64 version.

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B4X

Dim success As Boolean = False

'  Demonstrates the SFtp.ReadFileText64s method, which is like ReadFileText64 but takes the byte
'  offset as a decimal string.  The 1st argument is the handle, the 2nd is the offset string, the
'  3rd is the maximum number of bytes, and the 4th is the charset.

Dim sftp As ChilkatSFtp
sftp.Initialize("sftp")

'  Connect, authenticate, and initialize the SFTP subsystem.
Dim port As Int = 22
success = sftp.Connect("sftp.example.com", port)
If success = False Then
    Log(sftp.LastErrorText)
    Return
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 = "mySshPassword"

success = sftp.AuthenticatePw("mySshLogin", password)
If success = False Then
    Log(sftp.LastErrorText)
    Return
End If


success = sftp.InitializeSftp
If success = False Then
    Log(sftp.LastErrorText)
    Return
End If


Dim handle As String = sftp.OpenFile("subdir/hugefile.dat", "readOnly", "openExisting")
If sftp.LastMethodSuccess = False Then
    Log(sftp.LastErrorText)
    Return
End If


'  Supplying the offset as a string is convenient in languages without a native 64-bit integer.
Dim offset As String = "5000000000"
Dim numBytes As Int = 6
Dim text As String = sftp.ReadFileText64s(handle, offset, numBytes, "utf-8")
If sftp.LastMethodSuccess = False Then
    Log(sftp.LastErrorText)
    Return
End If

Log(text)

success = sftp.CloseHandle(handle)
If success = False Then
    Log(sftp.LastErrorText)
    Return
End If


sftp.Disconnect