Send email via SMTP with attachment, plain/text, and text/hml

Question

My goal: Send transactional emails via SMTP with plain/text, text/html, and attachments.

My code: Implemented with JavaMail

My issue: It looks fine on hotmail, or outlook. But on gmail, it does not show the message body properly if it is an email with a .txt attachment (it works alright if attachments are images)

Any help would be highly appreciated.

Here is my raw SMTP output:

Subject: ALTERNATIVE | TXT | HTML |ATT.ATTACHMENT | Thu Jun 13 17:48:04 EDT
 2013
MIME-Version: 1.0
Content-Type: multipart/alternative; 
    boundary="----=_Part_0_21791733.1371160084561"

------=_Part_0_21791733.1371160084561
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Body message in text format!
------=_Part_0_21791733.1371160084561
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit

Body message in <b>html</b> format! Sent on Thu Jun 13 17:48:04 EDT 2013<br> to: [email protected]<br> to: [email protected]<br> cc: [email protected]<br> cc: [email protected]
------=_Part_0_21791733.1371160084561
Content-Type: text/plain; charset=us-ascii; name=email_attachment.txt
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename=email_attachment.txt

This is a text attachment file!
------=_Part_0_21791733.1371160084561--
.
250 Delivery in progress
QUIT

Some screenshots

Sent with only one .txt attachment. The message body does not display and attachment are duplicated.

Same message but with different attachment (.gif). Everything looks fine.

=== SOLUTION FOR JAVA DEVELOPERS ====

The overall idea is described here: http://www.coderanch.com/t/503380/java/java/Java-Mail-text-html-attachment

So, now my code looks like:

// contentPart is the content to be sent. It is divided in bodyContent and attachmentContent
            MimeMultipart contentPart = new MimeMultipart("mixed");

            // Message body in txt and html format
            MimeMultipart bodyPart = new MimeMultipart("alternative");
            // Creates plain text message
            BodyPart bodyTxt = new MimeBodyPart();
            bodyTxt.setText(getMessageBodyText());
            // Creates html message
            BodyPart bodyHtml = new MimeBodyPart();
            bodyHtml.setContent(getMessageBodyHtml(), "text/html");
            bodyPart.addBodyPart(bodyTxt);
            bodyPart.addBodyPart(bodyHtml);

            // Wrapper for bodyTxt and bodyHtml
            MimeBodyPart bodyContent = new MimeBodyPart();
            bodyContent.setContent(bodyPart);

            // At this point, contentPart contains bodyTxt and bodyHtml wrapped in a multipart/alternative
            contentPart.addBodyPart(bodyContent);

            // Adds attachments to contentPart
            if (getAttachments() != null) {
                for(File f : getAttachments()) {
                    try {
                        MimeBodyPart attachmentPart = new MimeBodyPart();
                        attachmentPart.attachFile(f);
                        contentPart.addBodyPart(attachmentPart);
                    } catch (IOException e) {
                        logger.severe("Could not attach file to email!" +
                                " TO: "+ getTo().toString() +
                                "; CC: "+ getCc().toString() +
                                "; ExceptionMessage: " + e.getMessage());
                        throw new SmtpRequestException(e.getMessage());
                    }
                }
            }

Answer 1

The structure of your message is wrong. You need nested multiparts to get the right structure, something like this:

  multipart/mixed
    multipart/alternative (holding the two forms of the body part)
      text/plain
      text/html
    text/plain or image/gif (the attachment)