Rust
Get the Value of a MIME Header Field

Demonstrates how to get the value of a MIME header field. If the header field is not in the top-level MIME header, we must first navigate to the correct MIME part.
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// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

let mime = chilkat::Mime::new();

// The contents of this MIME file are shown below, 
// and is also available at https://www.chilkatsoft.com/sampleMime.txt
if mime.load_mime_file("qa_data/mime/sampleMime.txt").is_err() {
    println!("{}", mime.last_error_text());
    return;
}

// The MIME used in this example has the following nested structure
// 
// multipart/alternative
//     text/plain
//     multipart/related
//         text/html
//         image/jpeg
// 

// Getting the content of a top-level MIME header is easy.
// MIME header fields are case insensitive.
println!("Subject = {}", mime.get_header_field("subject").unwrap_or_default());
println!("MIME-Version = {}", mime.get_header_field("mime-version").unwrap_or_default());

// To get a MIME header in a sub-part, first navigate to it..

let mp_related = chilkat::Mime::new();
if mime.part_at(1, &mp_related).is_err() {
    println!("{}", mime.last_error_text());
    return;
}

let p_jpg = chilkat::Mime::new();
if mp_related.part_at(1, &p_jpg).is_err() {
    println!("{}", mp_related.last_error_text());
    return;
}

println!("JPG Content-ID = {}", p_jpg.get_header_field("content-id").unwrap_or_default());
println!("JPG Content-Type = {}", p_jpg.get_header_field("content-type").unwrap_or_default());

// --------------------------------------------------------------
// --------------------------------------------------------------
// The MIME sample file loaded at the beginning of this example
// contains the following MIME:

// Subject: Test email.
// Content-Type: multipart/alternative;
// 	boundary="------------DB171738719FB06D67DEBAA0"
// MIME-Version: 1.0
// 
// --------------DB171738719FB06D67DEBAA0
// Content-Type: text/plain; charset="utf-8"; format=flowed
// Content-Transfer-Encoding: 7bit
// 
// This is a test.
// 
// --------------DB171738719FB06D67DEBAA0
// Content-Type: multipart/related;
// 	boundary="------------A940F1230E6F0105F03DB2CB"
// 
// --------------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-Type: image/jpeg; name="starfish20.jpg"
// Content-Transfer-Encoding: base64
// Content-ID: <part1.E16AE3B4.1505C436@chilkatsoft.com>
// Content-Disposition: inline; filename="starfish20.jpg"
// 
// /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--
// 
// --------------DB171738719FB06D67DEBAA0--
//