java mailx multipart attachments from iphone missing

Question

I use javax.mail to download mails from a given mail address in order to get the attachments (I expect images) and save the images on disk automatically (polling the mail address). This works fine except if the mail has been sent from an iPhone. It seems that in these cases the image is embedded in the mail (I can see the image in the web mail window) and cannot be downloaded as an attachment.

• How can I extract the image from the mail?
• What is the difference between iPhone mails and other mails regarding attachments?
• Is the image a special part of the mail content?

In my program log I can see:
- contentType: multipart/mixed; boundary=Apple-Mail-...
- numberOfParts = 2

Java version is 1.7.0_21 javax.mail version is 1.4.7

This is the relevant code (most of it taken from http://www.codejava.net)

    if (contentType.contains("multipart")) {
      // content may contain attachments
      Multipart multiPart = (Multipart) message.getContent();
      numberOfParts = multiPart.getCount();
      for (int partCount = 0; partCount < numberOfParts; partCount++) {
        MimeBodyPart part = (MimeBodyPart) multiPart.getBodyPart(partCount);
        if (Part.ATTACHMENT.equalsIgnoreCase(part.getDisposition())) {
          // this part is the attachment
          String fileName = part.getFileName();
          attachFiles += fileName + ", ";
          if (fileName.endsWith("jpg") || fileName.endsWith("JPG")
              || fileName.endsWith("jpeg") || fileName.endsWith("JPEG")) {
            part.saveFile(saveDirectory + File.separator + fileName);
          } else {
            // attachment is not an image
          }
        } else {
          // this part may be the message content
          messageContent = part.getContent().toString();
        }
      }
      if (attachFiles.length() > 1) {
        attachFiles = attachFiles.substring(0, attachFiles.length() - 2);
      }
    } else if (contentType.contains("text/plain") || contentType.contains("text/html")) {
      Object content = message.getContent();
      if (content != null) {
        messageContent = content.toString();
      }
    }

Answer 1

The code you have is full of assumptions about the structure of a message. Most likely, one of those assumptions is wrong. Fire up a debugger, add some print statements, or do whatever is necessary to step through your code and compare what you're actually getting with what you expect to get. You can also dump the raw MIME content of the message using the Message.writeTo method, to see what the MIME structure of the message really is.

Probably the first thing to check is whether the image is marked as an ATTACHMENT. Perhaps it's being sent as INLINE instead?

BTW, you never want to use the filename in the message directly; someone could send you all sorts of malicious junk in there.