Rust

Fetch an IMAP Attachment into a BinData

Demonstrates the Chilkat Imap.FetchAttachmentBd method, which stores one attachment's bytes in a BinData object. The first argument is the Email, the second is the zero-based attachment index, and the third is the BinData, which is cleared before the operation. This example fetches the first attachment and prints its byte count.

Background: A BinData holds raw bytes, so it works for any attachment type — image, PDF, zip, and so on. From there you can save it, hash it, or hand it to another API expecting a byte buffer, all without touching the filesystem. Use the string/StringBuilder variants only when the attachment is known to be text.

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// Demonstrates the Imap.FetchAttachmentBd method, which downloads one attachment's bytes into
// a BinData object.  The 1st argument is the Email, the 2nd is the zero-based attachment
// index, and the 3rd is the BinData (which is cleared first).
// 
// The message is fetched headers-only, then the attachment is downloaded on demand.

let imap = chilkat::Imap::new();

imap.set_ssl(true);
imap.set_port(993);

if imap.connect("imap.example.com").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

if imap.login("user@example.com", "myPassword").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

if imap.select_mailbox("Inbox").is_err() {
    println!("{}", imap.last_error_text());
    return;
}

// Fetch only the message headers.  Attachment bodies are NOT downloaded, but the ckx-imap-*
// metadata describing the attachments is present, so the attachment info methods still work.
let headers_only = true;
let use_uid = false;
let seq_num = 1;
let email = chilkat::Email::new();
if imap.fetch_email(headers_only, seq_num as u32, use_uid, &email).is_err() {
    println!("{}", imap.last_error_text());
    return;
}

let num_attach = imap.get_mail_num_attach(&email);
if num_attach > 0 {
    // Download just the first attachment's bytes from the server into a BinData.
    let bd = chilkat::BinData::new();
    if imap.fetch_attachment_bd(&email, 0, &bd).is_err() {
        println!("{}", imap.last_error_text());
        return;
    }

    println!("Attachment size: {} bytes", bd.num_bytes());
}

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