CkPython

Write Text at a 64-bit Offset in a Remote SFTP File

Demonstrates the Chilkat SFtp.WriteFileText64 method, which encodes text and writes it at a specific 64-bit byte offset in an open handle. The arguments are the handle, the offset, the charset, and the text. The 64-bit offset supports very large files.

Background: A 32-bit offset tops out at about 4 GB, so files larger than that require the 64-bit form to address positions beyond that boundary. The behavior is otherwise identical to the 32-bit version — the only difference is the width of the offset argument, chosen to match the size of the file you are working with.

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import sys
import chilkat

success = False

#  Demonstrates the SFtp.WriteFileText64 method, which encodes text and writes it at a specific
#  64-bit byte offset in an open handle.  The 1st argument is the handle, the 2nd is the offset,
#  the 3rd is the charset, and the 4th is the text.  The 64-bit offset supports very large files.

sftp = chilkat.CkSFtp()

#  Connect, authenticate, and initialize the SFTP subsystem.
port = 22
success = sftp.Connect("sftp.example.com",port)
if (success == False):
    print(sftp.lastErrorText())
    sys.exit()

#  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.
password = "mySshPassword"

success = sftp.AuthenticatePw("mySshLogin",password)
if (success == False):
    print(sftp.lastErrorText())
    sys.exit()

success = sftp.InitializeSftp()
if (success == False):
    print(sftp.lastErrorText())
    sys.exit()

handle = sftp.openFile("subdir/hugefile.dat","readWrite","openOrCreate")
if (sftp.get_LastMethodSuccess() == False):
    print(sftp.lastErrorText())
    sys.exit()

#  Write at a byte offset beyond the 32-bit (4 GB) range.
offset = 5000000000
success = sftp.WriteFileText64(handle,offset,"utf-8","MARKER")
if (success == False):
    print(sftp.lastErrorText())
    sys.exit()

success = sftp.CloseHandle(handle)
if (success == False):
    print(sftp.lastErrorText())
    sys.exit()

print("Wrote at the 64-bit offset.")

sftp.Disconnect()