(Go) Build a multipart/related MIME Message

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

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

    var success bool

    // Start with an empty MIME object...
    mime := chilkat.NewMime()

    // Initialize it as multipart/related.
    mime.NewMultipartRelated()

    // Set a top-level MIME header field.
    mime.SetHeaderField("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.
    crypt := chilkat.NewCrypt2()
    crypt.SetEncodingMode("hex")

    sbContentId := chilkat.NewStringBuilder()
    sbContentId.Append("part1.")
    sbContentId.Append(*crypt.GenRandomBytesENC(4))
    sbContentId.Append(".")
    sbContentId.Append(*crypt.GenRandomBytesENC(4))
    sbContentId.Append("@chilkatsoft.com")

    // Create the HTML body.
    sbHtml := chilkat.NewStringBuilder()
    sbHtml.Append("<html><head>\r\n")
    sbHtml.Append("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=utf-8\">\r\n")
    sbHtml.Append("  </head>\r\n")
    sbHtml.Append("  <body bgcolor=\"#FFFFFF\" text=\"#000000\">\r\n")
    sbHtml.Append("    <p>This is a test.&nbsp; <img src=\"cid:CONTENT_ID\" height=\"20\" width=\"20\"></p>\r\n")
    sbHtml.Append("  </body>\r\n")
    sbHtml.Append("</html>\r\n")
    numReplacements := sbHtml.Replace("CONTENT_ID",*sbContentId.GetAsString())

    // Create the HTML MIME part.
    htmlMime := chilkat.NewMime()
    htmlMime.SetBodyFromHtml(*sbHtml.GetAsString())
    htmlMime.SetEncoding("8bit")
    htmlMime.SetCharset("utf-8")

    // Load our JPG image from a file.
    fac := chilkat.NewFileAccess()

    jpgBytes = fac.ReadEntireFile("qa_data/jpg/starfish20.jpg")

    // Create an image/jpeg MIME part.
    jpgMime := chilkat.NewMime()
    jpgMime.SetBodyFromBinary(jpgBytes)
    // 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.
    jpgMime.SetContentType("image/jpeg")
    jpgMime.SetName("starfish20.jpg")
    jpgMime.SetEncoding("base64")
    jpgMime.SetDisposition("inline")
    jpgMime.SetFilename("starfish20.jpg")

    sbContentIdHdr := chilkat.NewStringBuilder()
    sbContentIdHdr.Append("<CONTENT_ID>")
    numReplacements = sbContentIdHdr.Replace("CONTENT_ID",*sbContentId.GetAsString())
    jpgMime.SetHeaderField("Content-ID",*sbContentIdHdr.GetAsString())

    // Add both parts as children of the multipart/related
    mime.AppendPart(htmlMime)
    mime.AppendPart(jpgMime)
    fmt.Println(*mime.GetMime())

    // --------------------------------------------------------------
    // --------------------------------------------------------------
    // 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--
    // 

    mime.DisposeMime()
    crypt.DisposeCrypt2()
    sbContentId.DisposeStringBuilder()
    sbHtml.DisposeStringBuilder()
    htmlMime.DisposeMime()
    fac.DisposeFileAccess()
    jpgMime.DisposeMime()
    sbContentIdHdr.DisposeStringBuilder()