Rust

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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// 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.

let sftp = chilkat::SFtp::new();

// Connect, authenticate, and initialize the SFTP subsystem.
let port = 22;
if sftp.connect("sftp.example.com", port).is_err() {
    println!("{}", sftp.last_error_text());
    return;
}

// 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.
let password = "mySshPassword".to_string();

if sftp.authenticate_pw("mySshLogin", &password).is_err() {
    println!("{}", sftp.last_error_text());
    return;
}

if sftp.initialize_sftp().is_err() {
    println!("{}", sftp.last_error_text());
    return;
}

let Ok(handle) = sftp.open_file("subdir/record.dat", "readOnly", "openExisting") else {
    println!("{}", sftp.last_error_text());
    return;
};

// Read 5 bytes starting at byte offset 10, without first reading the bytes before it.
let offset = 10;
let num_bytes = 5;
let Ok(text) = sftp.read_file_text32(&handle, offset, num_bytes, "utf-8") else {
    println!("{}", sftp.last_error_text());
    return;
};

println!("{}", text);

if sftp.close_handle(&handle).is_err() {
    println!("{}", sftp.last_error_text());
    return;
}

sftp.disconnect();