Rust

Add a Content-Length Header to MIME

Demonstrates the Chilkat Mime.AddContentLength method, which computes the byte length of the entity's serialized body and adds or updates its Content-Length header. It takes no arguments and is a void method. The count is based on the transfer-encoded serialized body.

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

Background: Some protocols and consumers want a Content-Length declaring the body size up front. This computes it correctly from the encoded body — the bytes actually written — rather than the decoded content, and updates any existing header so it stays accurate. Call it after the body is final; if you change the body afterward, call it again, or remove the header, since a stale length is worse than none.

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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;
}

// Compute the byte length of the entity's serialized body and add (or update) its Content-Length
// header.  The count is based on the transfer-encoded serialized body.  It is a void method.
mime.add_content_length();

let Ok(content_length) = mime.get_header_field("Content-Length") else {
    println!("{}", mime.last_error_text());
    return;
};

println!("Content-Length: {}", content_length);