Rust

Add a Related Item from a BinData Object

Demonstrates the Chilkat Email.AddRelatedBd method, which adds a related item (such as an inline image) using the contents of a BinData object, and returns the generated Content-ID. This example loads an image into a BinData, adds it, captures the Content-ID, and references it from the HTML body.

Background: This is the binary, Content-ID-based way to embed an inline resource — the right choice for images, whose bytes belong in a BinData rather than a string. Because Chilkat generates the Content-ID, the usual pattern is: add the item first, capture the returned ID, then build the matching <img src="cid:..."> reference from it (done here with a StringBuilder).

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// Demonstrates the AddRelatedBd method, which adds a related item (such as an inline image)
// using the contents of a BinData object, and returns the generated Content-ID.

let email = chilkat::Email::new();
email.set_subject("Related image from BinData");

// Load the image data from a file into a BinData object.
let bd_image = chilkat::BinData::new();
if bd_image.load_file("qa_data/images/logo.png").is_err() {
    println!("{}", bd_image.last_error_text());
    return;
}

// Add the image as a related item; capture its generated Content-ID.
let Ok(cid) = email.add_related_bd("logo.png", &bd_image) else {
    println!("{}", email.last_error_text());
    return;
};

// Reference the related item in the HTML body by its Content-ID.
let sb_html = chilkat::StringBuilder::new();
let _ = sb_html.append("<html><body><img src=\"cid:PLACEHOLDER_CID\"/></body></html>");
let num_replaced = sb_html.replace("PLACEHOLDER_CID", &cid);
email.set_html_body(&sb_html.get_as_string().unwrap_or_default());

println!("NumRelatedItems = {}", email.num_related_items());

// Note: The path "qa_data/images/logo.png" is a relative local filesystem path,
// relative to the current working directory of the running application.