Rust
Build a multipart/related MIME Message

Demonstrates how to construct a multipart/related MIME message containing HTML and a related JPG image.
Chilkat Rust Downloads

Rust

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Start with an empty MIME object...
let mime = chilkat::Mime::new();

// Initialize it as multipart/related.
let _ = mime.new_multipart_related();

// Set a top-level MIME header field.
let _ = mime.set_header_field("Subject", "Test HTML email with JPG image.");

// Generate a Content-ID.  This will contain random data that will allow
// the HTML's "img" tag to reference the image part in the MIME.
let crypt = chilkat::Crypt2::new();
crypt.set_encoding_mode("hex");

let sb_content_id = chilkat::StringBuilder::new();
let _ = sb_content_id.append("part1.");
let _ = sb_content_id.append(&crypt.gen_random_bytes_enc(4).unwrap_or_default());
let _ = sb_content_id.append(".");
let _ = sb_content_id.append(&crypt.gen_random_bytes_enc(4).unwrap_or_default());
let _ = sb_content_id.append("@chilkatsoft.com");

// Create the HTML body.
let sb_html = chilkat::StringBuilder::new();
let _ = sb_html.append("<html><head>\r\n");
let _ = sb_html.append("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\r\n");
let _ = sb_html.append("  </head>\r\n");
let _ = sb_html.append("  <body bgcolor=\"#FFFFFF\" text=\"#000000\">\r\n");
let _ = sb_html.append("    <p>This is a test.&nbsp; <img src=\"cid:CONTENT_ID\" height=\"20\" width=\"20\"></p>\r\n");
let _ = sb_html.append("  </body>\r\n");
let _ = sb_html.append("</html>\r\n");
let mut num_replacements = sb_html.replace("CONTENT_ID", &sb_content_id.get_as_string().unwrap_or_default());

// Create the HTML MIME part.
let html_mime = chilkat::Mime::new();
let _ = html_mime.set_body_from_html(&sb_html.get_as_string().unwrap_or_default());
html_mime.set_encoding("8bit");
html_mime.set_charset("utf-8");

// Load our JPG image from a file.
let fac = chilkat::FileAccess::new();

jpg_bytes = fac.read_entire_file("qa_data/jpg/starfish20.jpg");

// Create an image/jpeg MIME part.
let jpg_mime = chilkat::Mime::new();
let _ = jpg_mime.set_body_from_binary(&jpg_bytes);
// Setting the following properties has the effect of adding
// the Content-Type, Content-Transfer-Encoding, and Content-Disposition header fields.
// These header fields could also be set via the SetHeaderField method, in which case
// the values of the affected properties would be updated.
jpg_mime.set_content_type("image/jpeg");
jpg_mime.set_name("starfish20.jpg");
jpg_mime.set_encoding("base64");
jpg_mime.set_disposition("inline");
jpg_mime.set_filename("starfish20.jpg");

let sb_content_id_hdr = chilkat::StringBuilder::new();
let _ = sb_content_id_hdr.append("<CONTENT_ID>");
num_replacements = sb_content_id_hdr.replace("CONTENT_ID", &sb_content_id.get_as_string().unwrap_or_default());
let _ = jpg_mime.set_header_field("Content-ID", &sb_content_id_hdr.get_as_string().unwrap_or_default());

// Add both parts as children of the multipart/related
let _ = mime.append_part(&html_mime);
let _ = mime.append_part(&jpg_mime);
println!("{}", mime.get_mime().unwrap_or_default());

// --------------------------------------------------------------
// --------------------------------------------------------------
// This example builds the following MIME message.  The boundary
// and Content-ID strings contain random data and will be different.  

// Content-Type: multipart/related; boundary="------------A940F1230E6F0105F03DB2CB"
// Subject: Test HTML email with JPG image.
// 
// --------------A940F1230E6F0105F03DB2CB
// Content-Type: text/html; charset="utf-8"
// Content-Transfer-Encoding: 8bit
// 
// <html><head>
// <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
//   </head>
//   <body bgcolor="#FFFFFF" text="#000000">
//     <p>This is a test.&nbsp; <img src="cid:part1.E16AE3B4.1505C436@chilkatsoft.com" height="20" width="20"></p>
//   </body>
// </html>
// 
// --------------A940F1230E6F0105F03DB2CB
// Content-Transfer-Encoding: base64
// Content-Type: image/jpeg; name="starfish20.jpg"
// Content-Disposition: inline; filename="starfish20.jpg"
// Content-ID: <part1.E16AE3B4.1505C436@chilkatsoft.com>
// 
// /9j/4AAQSkZJRgABAQEASABIAAD//gAmRmlsZSB3cml0dGVuIGJ5IEFkb2JlIFBob3Rvc2hvcD8g
// NC4w/9sAQwAQCwwODAoQDg0OEhEQExgoGhgWFhgxIyUdKDozPTw5Mzg3QEhcTkBEV0U3OFBtUVdf
// YmdoZz5NcXlwZHhcZWdj/9sAQwEREhIYFRgvGhovY0I4QmNjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj
// Y2NjY2NjY2NjY2NjY2NjY2NjY2NjY2NjY2Nj/8IAEQgAFAAUAwERAAIRAQMRAf/EABcAAAMBAAAA
// AAAAAAAAAAAAAAIDBAX/xAAYAQADAQEAAAAAAAAAAAAAAAABAgMEAP/aAAwDAQACEAMQAAAB2kZY
// NNEijWKddfTmLgALWH//xAAbEAACAgMBAAAAAAAAAAAAAAABAgMRAAQSE//aAAgBAQABBQL0XqN+
// pM2aqJGMiqFFCyg7z//EABwRAAICAgMAAAAAAAAAAAAAAAERAAIQIQMSUf/aAAgBAwEBPwHqU5aq
// Axx+y1tMQl4elj//xAAcEQEAAQUBAQAAAAAAAAAAAAABEQACEBIhA1H/2gAIAQIBAT8B3Bhqy7Zc
// enyiwmGgDhiOzj//xAAdEAABAwUBAAAAAAAAAAAAAAABAAIREBIhIkFR/9oACAEBAAY/ArZyn+Cg
// xtxWuJaoCnqDuin/xAAcEAABBAMBAAAAAAAAAAAAAAABABEhYRAxQVH/2gAIAQEAAT8hkEwPUUR9
// DYfE4nxtRpIkBTsayuALIiuY/9oADAMBAAIAAwAAABDWPTsf/8QAGhEAAwADAQAAAAAAAAAAAAAA
// AAEREDFBIf/aAAgBAwEBPxC0DVPcWm+Ce4OesrkE6bjH/8QAGBEBAQEBAQAAAAAAAAAAAAAAAREA
// QRD/2gAIAQIBAT8QahMiOc8YgSrnTY3ELclHXn//xAAcEAEBAAIDAQEAAAAAAAAAAAABEQAhMUFx
// EFH/2gAIAQEAAT8Qn3igmSZSj+c4N4zapMy9IjFV98wncN2iuLFsCEbDGxQkI6RO/n//2Q==
// 
// --------------A940F1230E6F0105F03DB2CB--
//