Rust

Convert a MIME Entity to multipart/mixed

Demonstrates the Chilkat Mime.ConvertToMultipartMixed method, which wraps the current entity in a new outer multipart/mixed, making the original the first child. It takes no arguments.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is how you turn an existing single-part message into one that can hold attachments — rather than rebuilding it, you wrap it, and its content becomes the first child of a new multipart/mixed. Message-level and custom headers are carried onto the new outer entity so the message identity is preserved. Afterward, AppendPartFromFile adds attachments beside the original body.

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Rust


let mime = chilkat::Mime::new();
if mime.load_mime_file("qa_data/message.eml").is_err() {
    println!("{}", mime.last_error_text());
    return;
}

// Wrap the current entity in a new outer multipart/mixed entity.  The original entity becomes the
// first child, which is what you do to add attachments to an existing single-part message.
if mime.convert_to_multipart_mixed().is_err() {
    println!("{}", mime.last_error_text());
    return;
}

// Now attachments can be appended alongside the original content.
if mime.append_part_from_file("qa_data/report.pdf").is_err() {
    println!("{}", mime.last_error_text());
    return;
}

println!("Number of parts: {}", mime.num_parts());