CkPython

Read Text at a 64-bit Offset from a Remote SFTP File

Demonstrates the Chilkat SFtp.ReadFileText64 method, which reads up to a number of bytes from a specific 64-bit byte offset of an open handle and decodes them to text. The arguments are the handle, the offset, the maximum number of bytes, and the charset. The 64-bit offset supports very large files.

Background: This is the large-file counterpart to reading at a 32-bit offset: use it whenever the position you need lies beyond the ~4 GB reach of a 32-bit integer, for example seeking into a multi-gigabyte archive or database file. Everything else about the read is the same.

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import sys
import chilkat

success = False

#  Demonstrates the SFtp.ReadFileText64 method, which reads up to a number of bytes from a
#  specific 64-bit byte offset of an open handle and decodes them to text.  The 1st argument is
#  the handle, the 2nd is the offset, the 3rd is the maximum number of bytes, and the 4th is the
#  charset.  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","readOnly","openExisting")
if (sftp.get_LastMethodSuccess() == False):
    print(sftp.lastErrorText())
    sys.exit()

#  Read 6 bytes starting at a byte offset beyond the 32-bit (4 GB) range.
offset = 5000000000
numBytes = 6
text = sftp.readFileText64(handle,offset,numBytes,"utf-8")
if (sftp.get_LastMethodSuccess() == False):
    print(sftp.lastErrorText())
    sys.exit()

print(text)

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

sftp.Disconnect()