Rust

Pre-Allocate Server Space Before an FTP Upload (ALLO)

Demonstrates the AllocateSize property, which sends the FTP ALLO command to pre-allocate disk space on the server before an upload. Set it to the size in bytes of the file about to be uploaded.

Background: ALLO asks the server to reserve storage in advance, a requirement of certain legacy systems — older mainframes in particular — that need the exact file size up front to allocate a dataset. Modern servers allocate space dynamically and typically ignore or accept ALLO without needing it, so most applications never set this. Provide it only when targeting a host known to require pre-allocation.

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Rust


let ftp = chilkat::Ftp2::new();

ftp.set_hostname("ftp.example.com");
ftp.set_username("myFtpLogin");

// 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.
ftp.set_password("myPassword");

if ftp.connect().is_err() {
    println!("{}", ftp.last_error_text());
    return;
}

// AllocateSize sends the FTP ALLO command to pre-allocate disk space on the server before an
// upload.  It is rarely needed -- mainly for certain legacy systems that require the exact size
// in advance -- since most servers allocate space dynamically.  Set it to the size in bytes of
// the file about to be uploaded.
ERROR: Assignment type mismatch.  ExpressionType=int, atgType=uint

if ftp.put_file("qa_data/bigfile.zip", "uploads/bigfile.zip").is_err() {
    println!("{}", ftp.last_error_text());
    return;
}

println!("Uploaded with pre-allocation.");

if ftp.disconnect().is_err() {
    println!("{}", ftp.last_error_text());
    return;
}