Ruby

Get the Byte Count of the Last SFTP Read

Demonstrates the Chilkat SFtp.LastReadNumBytes method, which returns the number of bytes received by the most recent read for a handle. The only argument is the handle.

Background: SFTP reads may return fewer bytes than requested even before the end of the file, so knowing the actual count is useful for tracking progress and for advancing an explicit offset by the right amount. Both a normal EOF read and a failed read report 0, so pair this with Eof and LastReadFailed to interpret a zero-byte result correctly.

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Ruby

require 'chilkat'

success = false

#  Demonstrates the SFtp.LastReadNumBytes method, which returns the number of bytes received by
#  the most recent read for a handle.  The only argument is the handle.

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/data.txt","readOnly","openExisting")
if (sftp.get_LastMethodSuccess() == false)
    print sftp.lastErrorText() + "\n";
    exit
end

bd = Chilkat::CkBinData.new()
chunkSize = 4096
reading = true
while reading
    success = sftp.ReadFileBd(handle,chunkSize,bd)
    if (sftp.LastReadFailed(handle))
        print sftp.lastErrorText() + "\n";
        exit
    end

    #  Report how many bytes the last read actually returned.  A normal EOF read reports 0.
    lastCount = sftp.LastReadNumBytes(handle)
    print "Last read returned " + lastCount.to_s() + " bytes." + "\n";

    reading = !sftp.Eof(handle)
end

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

print "Total: " + bd.get_NumBytes().to_s() + " bytes." + "\n";

sftp.Disconnect()