Image embedding in Java mail - CID not working

java html image email

19,211

I found that there wasn't anything wrong with the mail source. It's the way mailclients handle CIDs. Gmail.com requires the CID to be set between < and >. Thunderbird hasn't shown my images yet.. I think it needs to be unique of some sort.. Still haven't figured why and how to fix it. Found it through Embedding images into html email with java mail

19,211

Author by

krobbens

Updated on August 23, 2022

Comments

krobbens over 1 year

I'm working on an application to send mails to lists etc. It's written in Java using the javax.mail api. The problem here is, I can't embed images using a CID.

This is the source of the mail that is sent:

Delivered-To: [email protected]
Received: by 10.43.50.4 with SMTP id vc4csp85536icb;
        Tue, 17 Apr 2012 05:08:00 -0700 (PDT)
Received: by 10.204.141.25 with SMTP id k25mr4406030bku.72.1334664479298;
        Tue, 17 Apr 2012 05:07:59 -0700 (PDT)
Return-Path: <[email protected]>
Received: from mail-bk0-f43.google.com (mail-bk0-f43.google.com [209.85.214.43])
        by mx.google.com with ESMTPS id ad16si7984294bkc.150.2012.04.17.05.07.58
        (version=TLSv1/SSLv3 cipher=OTHER);
        Tue, 17 Apr 2012 05:07:59 -0700 (PDT)
Received-SPF: pass (google.com: domain of [email protected] designates 209.85.214.43 as permitted sender) client-ip=209.85.214.43;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of - designates 209.85.214.43 as permitted sender) smtp.mail=-; dkim=pass [email protected]
Received: by mail-bk0-f43.google.com with SMTP id j5so5978375bkw.2
        for <[email protected]>; Tue, 17 Apr 2012 05:07:58 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=gmail.com; s=20120113;
        h=date:from:to:message-id:subject:mime-version:content-type;
        bh=Xj44O9fBIzirvcquOGxJbYLtbqgBc2Ags7prNUuAtSQ=;
        b=WWTCdrFgs3RCT/g2qXHR0fLCTc73TmNMA15sff0oIDksB6Nn3IwTYAqTVmoGiNrkW5
         08WDpTRADEKAOvjQ5FC9/uBCh1RXWTjxtawfjHc7vfUpqKbXOCj8Ab6GWXQMmX/+WB6T
         KVYLhk3/+GddIJI1XsAX9zprSYVcP6MMJ5/U+idIDlC7xQGGNuvzvpAnlnlGuWzgKc6j
         qPoFSAAaio6zICY9uSaI0deBIYTEQ2hIuBDJG8oaRvGVvpjhzJaBK+ab+rPJEboHPg8S
         3WSCG/Pp212VOw/YXOLUQV0jmMbuqAbsGdeER+Okbwe11sWi+zvPz+jhplB0NB2wq0Fn
         mWzA==
Received: by 10.204.130.13 with SMTP id q13mr4084640bks.128.1334664478358;
        Tue, 17 Apr 2012 05:07:58 -0700 (PDT)
Return-Path: <[email protected]>
Received: from Akoya ([xx])
        by mx.google.com with ESMTPS id z14sm37467763bky.15.2012.04.17.05.07.51
        (version=SSLv3 cipher=OTHER);
        Tue, 17 Apr 2012 05:07:54 -0700 (PDT)
Date: Tue, 17 Apr 2012 05:07:54 -0700 (PDT)
From: BP MM <[email protected]>
To: xx xx <[email protected]>
Message-ID: <404745073.01334664469900.JavaMail.xx@Akoya>
Subject: TestImage
MIME-Version: 1.0
Content-Type: multipart/mixed; 
    boundary="----=_Part_2_854532868.1334664469871"

------=_Part_2_854532868.1334664469871
Content-Type: multipart/mixed; 
    boundary="----=_Part_1_1457048287.1334664469871"

------=_Part_1_1457048287.1334664469871
Content-Type: image/png; name=logo.png
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename=logo.png
Content-ID: img_cid

[base64 data]
------=_Part_1_1457048287.1334664469871--

------=_Part_2_854532868.1334664469871
Content-Type: multipart/alternative; 
    boundary="----=_Part_0_1033690582.1334664469858"

------=_Part_0_1033690582.1334664469858
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hello


------=_Part_0_1033690582.1334664469858
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit

<html>
<body>
<H1>Hello</H1>
<img src="cid:img_cid">
</body>
</html>

------=_Part_0_1033690582.1334664469858--

------=_Part_2_854532868.1334664469871--

I've tried different CID's, adding < and > to the CID, setting disposition to inline, validated HTML etc. Can't get this to work, Thunderbird and Gmail view the mail with 'dead' images. I've read that the client looks for the cid in the mail, so I figuered it should fetch the image correctly. Sending the attachment does work, but embedding doesn't. Anyone that has a clue? Is it related to the Multipart structure?

The java code for creating the message (i've commented some lines trying to solve it..)

    /*
     * The method to create a MimeMessage, this message can be sent with the transport method.
     */
    private Message createMessage(final Mail mail, final Member member, final MailingList list,
            final MailAccount mailAccount, final Session session)
            throws MessagingException, UnsupportedEncodingException {
        // Get attachments
        @SuppressWarnings("unchecked")
        List<File> attachments = (List<File>) mail.getProperty(Mail.ATTACHMENTS_KEY);

        // Create content parts
        String plainContent = templateEngine.replaceTemplateTags(mail, member, list, mailAccount);
        String htmlContent = templateEngine.replaceHTMLTemplateTags(mail, member, list, mailAccount);

        Multipart multiContentPart = new MimeMultipart("alternative");
//      Multipart attachmentsBodyPart = new MimeMultipart();
        Multipart rootBodyPart = new MimeMultipart();

        // Create plain text part
        if (!plainContent.equals("")) {
            BodyPart plainMessageBodyPart = new MimeBodyPart();
            plainMessageBodyPart.setContent(plainContent, "text/plain");
            multiContentPart.addBodyPart(plainMessageBodyPart);
        }

        // Create html part
        if (!htmlContent.equals("")) {
            BodyPart htmlMessageBodyPart = new MimeBodyPart();
            htmlMessageBodyPart.setContent(htmlContent, "text/html");
            multiContentPart.addBodyPart(htmlMessageBodyPart);
        }

        // Create attachments
        if (attachments != null && attachments.size() > 0) {
            for (int i = 0; i < attachments.size(); i++) {
                BodyPart attachmentBodyPart = new MimeBodyPart();
                DataSource source = new FileDataSource(attachments.get(i));
                attachmentBodyPart.setDataHandler(new DataHandler(source));
                attachmentBodyPart.setFileName(attachments.get(i).getName());
                attachmentBodyPart.setHeader("Content-ID", "<img_cid>");
                attachmentBodyPart.setDisposition(Part.INLINE);
//              attachmentsBodyPart.addBodyPart(attachmentBodyPart);
                rootBodyPart.addBodyPart(attachmentBodyPart);
            }
            // Build attachments
//          BodyPart attachmentsWrapper = new MimeBodyPart();
//          attachmentsWrapper.setContent(attachmentsBodyPart);
//          rootBodyPart.addBodyPart(attachmentsWrapper);
        }

        // Build content
        BodyPart contentWrapper = new MimeBodyPart();
        contentWrapper.setContent(multiContentPart);
        rootBodyPart.addBodyPart(contentWrapper);

        // Create message
        Message message = new MimeMessage(session);
        message.setRecipient(Message.RecipientType.TO, new InternetAddress(
                member.getEmail(), member.getName()));
        message.setSubject((String) mail.getProperty(Mail.SUBJECT_KEY));
        message.setContent(rootBodyPart);

        // Add headers
        message.setFrom(new InternetAddress(mailAccount.getFromAddress(),
                mailAccount.getFromName()));
        if (mailAccount.getReplyTo() != "" && mailAccount.getReplyTo() != null)
            message.setReplyTo(InternetAddress.parse(mailAccount.getReplyTo()));

        return message;
    }

Don't mind the CID being the same for each attachment, later this will be the file name - I'm only testing with a single attachment for now. Hope this helps..

krobbens about 12 years

It seems to be due to the wrong content type of the MIME format. I think the structure of the body parts are wrong. The one that doesn't work has: Content-Type: multipart/mixed; this should work: Content-Type: multipart/related; type="multipart/alternative"; I haven't found the correct structure yet to display text/html/embedded images as it should.
krobbens about 12 years

The solution is a combination of the cid reference and the multipart structure. Validate your cid (needs < and >, sometimes an @). Make sure your root is multipart/relative, add the multipart/alternative of html/text to it (wrapped in a bodypart) and afterwards add the attachments to the root part (each in its own bodypart). See coderanch.com/t/503380/java/java/Java-Mail-text-html-attachm‌ent
krobbens about 12 years

A very good source for combining body parts blogs.technet.com/b/exchange/archive/2011/04/21/…
JDJ about 10 years

To make it work in Thunderbird, remove this line: attachmentBodyPart.setHeader("Content-ID", "<img_cid>"); and add these two lines: attachmentBodyPart.addHeader("Content-ID", "<img_cid>"); attachmentBodyPart.addHeader("Content-Type", "image/png"); This assumes that you have the following somewhere in your HTML body: <img src=\"cid:img_cid\">