Perl

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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Perl

use chilkat();

$success = 0;

#  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->new();

#  Connect, authenticate, and initialize the SFTP subsystem.
$port = 22;
$success = $sftp->Connect("sftp.example.com",$port);
if ($success == 0) {
    print $sftp->lastErrorText() . "\r\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.
$password = "mySshPassword";

$success = $sftp->AuthenticatePw("mySshLogin",$password);
if ($success == 0) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

$success = $sftp->InitializeSftp();
if ($success == 0) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

$handle = $sftp->openFile("subdir/hugefile.dat","readOnly","openExisting");
if ($sftp->get_LastMethodSuccess() == 0) {
    print $sftp->lastErrorText() . "\r\n";
    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() == 0) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

print $text . "\r\n";

$success = $sftp->CloseHandle($handle);
if ($success == 0) {
    print $sftp->lastErrorText() . "\r\n";
    exit;
}

$sftp->Disconnect();