(Go) Send HTML Email with CSS as Related Item using Content-Location

Demonstrates how to compose an HTML email with an external CSS file included as a related item and referenced by Content-Location.

Some email clients display embedded (related) content best using CID's (Content-IDs), whereas other email clients display related content best by Content-Location. The choice you make may depend on the software used by the intended recipient of your email. (Does' the recipient read email on an iPhone? Android? Outlook? GMail? Thunderbird? etc.)

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

    // The mailman object is used for sending and receiving email.
    mailman := chilkat.NewMailMan()

    // Use your SMTP server hostname.  This example uses office365, but it could be any SMTP server..
    mailman.SetSmtpHost("outlook.office365.com")
    mailman.SetSmtpPort(587)
    mailman.SetStartTLS(true)

    // Set the SMTP login/password
    mailman.SetSmtpUsername("OFFICE365-SMTP-LOGIN")
    mailman.SetSmtpPassword("OFFICE365-SMTP-PASSWORD")

    // Create a new email object
    email := chilkat.NewEmail()
    email.SetSubject("HTML Email with embedded CSS")
    email.SetFrom("Chilkat Support <my-office365-user@mydomain.com>")
    email.AddTo("Chilkat Support","support@chilkatsoft.com")

    sbCss := chilkat.NewStringBuilder()
    bCrlf := true
    sbCss.AppendLine("body {",bCrlf)
    sbCss.AppendLine("    background-color: powderblue;",bCrlf)
    sbCss.AppendLine("}",bCrlf)
    sbCss.AppendLine("h1 {",bCrlf)
    sbCss.AppendLine("    color: blue;",bCrlf)
    sbCss.AppendLine("}",bCrlf)
    sbCss.AppendLine("p {",bCrlf)
    sbCss.AppendLine("    color: red;",bCrlf)
    sbCss.AppendLine("}",bCrlf)

    // The filenameInHtml is what should exists within the HTML (in the href atribute)
    filenameInHtml := "styles.css"
    // Call AddRelatedString2 to use Content-Location.
    email.AddRelatedString2(filenameInHtml,*sbCss.GetAsString(),"utf-8")

    sbHtml := chilkat.NewStringBuilder()
    sbHtml.AppendLine("<!DOCTYPE html>",bCrlf)
    sbHtml.AppendLine("<html>",bCrlf)
    sbHtml.AppendLine("<head>",bCrlf)
    sbHtml.AppendLine("  <link rel=\"stylesheet\" href=\"styles.css\">",bCrlf)
    sbHtml.AppendLine("</head>",bCrlf)
    sbHtml.AppendLine("<body>",bCrlf)
    sbHtml.AppendLine("",bCrlf)
    sbHtml.AppendLine("<h1>This is a heading</h1>",bCrlf)
    sbHtml.AppendLine("<p>This is a paragraph.</p>",bCrlf)
    sbHtml.AppendLine("",bCrlf)
    sbHtml.AppendLine("</body>",bCrlf)
    sbHtml.AppendLine("</html>",bCrlf)

    email.SetHtmlBody(*sbHtml.GetAsString())

    success := mailman.SendEmail(email)
    if success != true {
        fmt.Println(mailman.LastErrorText())
    }
    else {
        fmt.Println("Mail Sent!")
    }


    mailman.DisposeMailMan()
    email.DisposeEmail()
    sbCss.DisposeStringBuilder()
    sbHtml.DisposeStringBuilder()