Rust

Send a Raw SMTP Command

Demonstrates the Chilkat MailMan.SmtpSendRawCommand method, which sends a raw command to the SMTP server and returns the server's response. The second argument specifies the charset to use if the command contains non-US-ASCII characters, and the third indicates whether to base64-encode the command before sending. This example sends a raw NOOP on an open connection.

Background: SMTP is a line-based text protocol (EHLO, MAIL FROM, RCPT TO, DATA, QUIT), so a raw-command hook lets you issue anything Chilkat doesn't wrap — a server extension, or a custom step during a manual auth exchange. The base64 flag exists because some SMTP exchanges (notably AUTH challenge/response) require the argument to be base64-encoded on the wire.

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Rust


// Demonstrates the MailMan.SmtpSendRawCommand method, which sends a raw command to the SMTP
// server and returns the server's response.  The 2nd argument is the charset used if the
// command contains non-US-ASCII characters, and the 3rd indicates whether to base64-encode
// the command before sending.

let mailman = chilkat::MailMan::new();

// Configure the SMTP server connection.
mailman.set_smtp_host("smtp.example.com");
mailman.set_smtp_port(465);
mailman.set_smtp_ssl(true);
mailman.set_smtp_username("user@example.com");
mailman.set_smtp_password("myPassword");

if mailman.open_smtp_connection().is_err() {
    println!("{}", mailman.last_error_text());
    return;
}

// Send the raw SMTP NOOP command (not base64-encoded).
let Ok(response) = mailman.smtp_send_raw_command("NOOP", "us-ascii", false) else {
    println!("{}", mailman.last_error_text());
    return;
};

println!("NOOP response: {}", response);

if mailman.close_smtp_connection().is_err() {
    println!("{}", mailman.last_error_text());
    return;
}