Perl

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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use strict;
use warnings;
use Chilkat2;

# 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.

my $sftp = Chilkat2::SFtp->new;

# Connect, authenticate, and initialize the SFTP subsystem.
my $port = 22;
my $success = $sftp->Connect('sftp.example.com', $port);
if (!$success) {
    print $sftp->LastErrorText, "\n";
    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.
my $password = 'mySshPassword';

$success = $sftp->AuthenticatePw('mySshLogin', $password);
if (!$success) {
    print $sftp->LastErrorText, "\n";
    exit;
}

$success = $sftp->InitializeSftp();
if (!$success) {
    print $sftp->LastErrorText, "\n";
    exit;
}

my $handle = $sftp->OpenFile('subdir/hugefile.dat', 'readOnly', 'openExisting');
if (!$sftp->LastMethodSuccess) {
    print $sftp->LastErrorText, "\n";
    exit;
}

# Supplying the offset as a string is convenient in languages without a native 64-bit integer.
my $offset = '5000000000';
my $numBytes = 6;
my $text = $sftp->ReadFileText64s($handle, $offset, $numBytes, 'utf-8');
if (!$sftp->LastMethodSuccess) {
    print $sftp->LastErrorText, "\n";
    exit;
}

print $text, "\n";

$success = $sftp->CloseHandle($handle);
if (!$success) {
    print $sftp->LastErrorText, "\n";
    exit;
}

$sftp->Disconnect();