PHP

Read Text at a 32-bit Offset from a Remote SFTP File

Demonstrates the Chilkat SFtp.ReadFileText32 method, which reads up to a number of bytes from a specific 32-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.

Background: Reading from an explicit offset lets you fetch just the part of a file you need — a header, a record at a known position, a slice of a large log — without downloading everything before it. As with offset writes, the offset counts bytes rather than characters, so it must respect the encoded width of any multibyte content.

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<?php

use Chilkat2\SFtp;

// Demonstrates the SFtp.ReadFileText32 method, which reads up to a number of bytes from a
// specific 32-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.

$sftp = new SFtp();

// Connect, authenticate, and initialize the SFTP subsystem.
$port = 22;
try {
    $sftp->Connect('sftp.example.com', $port);

    // 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';

    $sftp->AuthenticatePw('mySshLogin', $password);

    $sftp->InitializeSftp();

    $handle = $sftp->OpenFile('subdir/record.dat', 'readOnly', 'openExisting');

    // Read 5 bytes starting at byte offset 10, without first reading the bytes before it.
    $offset = 10;
    $numBytes = 5;
    $text = $sftp->ReadFileText32($handle, $offset, $numBytes, 'utf-8');
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo $text, "\n";

try {
    $sftp->CloseHandle($handle);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

$sftp->Disconnect();