Ruby

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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require 'chilkat'

success = 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.

sftp = Chilkat::CkSFtp.new()

#  Connect, authenticate, and initialize the SFTP subsystem.
port = 22
success = sftp.Connect("sftp.example.com",port)
if (success == false)
    print sftp.lastErrorText() + "\n";
    exit
end

#  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() + "\n";
    exit
end

success = sftp.InitializeSftp()
if (success == false)
    print sftp.lastErrorText() + "\n";
    exit
end

handle = sftp.openFile("subdir/hugefile.dat","readOnly","openExisting")
if (sftp.get_LastMethodSuccess() == false)
    print sftp.lastErrorText() + "\n";
    exit
end

#  Supplying the offset as a string is convenient in languages without a native 64-bit integer.
offset = "5000000000"
numBytes = 6
text = sftp.readFileText64s(handle,offset,numBytes,"utf-8")
if (sftp.get_LastMethodSuccess() == false)
    print sftp.lastErrorText() + "\n";
    exit
end

print text + "\n";

success = sftp.CloseHandle(handle)
if (success == false)
    print sftp.lastErrorText() + "\n";
    exit
end

sftp.Disconnect()