[TYPO3-dev] t3lib_htmlmail breaks plaintext version when inline images are attached

[Simon Tuck]

Hi,
I'm using t3lib_htmlmail to send html emails with a plaintext 
alternative and inline images. Unsuccessfully so far. So long as the 
email doesn't contain any images the plaintext version of the mail is 
available as an alternative in my mail client. However, as soon as the 
message has one or more inline images the plaintext version of the 
message is no longer available.
As far as I can tell (from googling the issue and experimenting with the 
raw source of the email) the structure of the multipart mail is wrong.

The structure I get from t3lib_htmlmail is:

[SNIPPET]
Content-Type: multipart/related;
	boundary="----------boundary_related"

----------boundary_related
Content-Type: multipart/alternative;
	boundary="----------boundary_alternative"

	----------boundary_alternative
	Content-Type: text/plain;
		charset=utf-8
	
	----------boundary_alternative
	Content-Type: text/html;
		charset=utf-8
	
	----------boundary_alternative--

----------boundary_related
Content-Id: <xyz.1>
Content-Type: image/gif


----------boundary_related
Content-Id: <xyz.2>
Content-Type: image/jpeg

----------boundary_related--
[/SNIPPET]

The multipart/alternative which contains the html & plaintext versions 
of the mail is enclosed in a multipart/related which attaches the inline 
images. Using this source my mail client renders the html version ofthe 
mail properly but fails to detect the plaintext version of the email.

Some experimentation led me to the following message structure, which 
works as desired:

[SNIPPET]
Content-Type: multipart/alternative;
	boundary="----------boundary_alternative"

----------boundary_alternative
Content-Type: text/plain;
	charset=utf-8

------------boundary_alternative
	Content-Type: multipart/related;
		boundary="----------boundary_related"
	
	----------boundary_related
	Content-Type: text/html;
		charset=utf-8
	
	----------boundary_related
	Content-Id: <xyz.2>
	Content-Type: image/gif
	
	----------boundary_related
	Content-Id: <xyz.1>
	Content-Type: image/gif
	
	----------boundary_related--

----------boundary_alternative--
[/SNIPPET]

Here the multipart/alternative encloses the multipart/related which 
attaches the inline images to the html version only.

I'm no expert on multipart message formats, does anyone have anymore 
insight into this issue: Is this a bug in t3lib_htmlmail or am I using 
the t3lib_htmlmail class wrongly (or is my mail client wrong - I'm using 
apple mail btw)?
The code I am running to create and send an email is roughly as follows:

[SNIPPET]
// Get an instance of the TYPO3 mailer class
$this->mailer = t3lib_div::makeInstance('t3lib_htmlmail');
$this->mailer->start();

// Set the encoding to base64
$this->mailer->useBase64();

// Get/set the recipient(s)
if(!is_array($recipients)) $recipients = t3lib_div::trimExplode(',', 
$recipients, 1);
$this->mailer->setRecipient($recipients);

// Subject
$this->mailer->subject = $subject;

// Sender information
$this->mailer->from_email = $fromEMail;
$this->mailer->from_name = $fromName;
$this->mailer->organisation = $organisation ? $organisation : '';

// Return path
$this->mailer->replyto_email = $fromEMail;
$this->mailer->replyto_name = $fromName;
$this->mailer->returnPath = $fromEMail;

// Xid
$this->mailer->Xid = md5(uniqid(mt_rand(), true));

// Add the plaintext version
$this->mailer->addPlain($text);
		
// Get the HTML version from the file
$this->addHtml($file);

// Add attachments
if(!empty($attachments)) {
	foreach ($attachments as $attachment) {
		$attachment = t3lib_div::getFileAbsFileName($attachment, false);
		if(@is_readable($attachment)) {
			if($attachment) $this->mailer->addAttachment($attachment);
		}
	}
}
		
// Send the mail
$this->mailer->setHeaders();
$this->mailer->setContent();
$mailWasSent = $this->mailer->sendTheMail();
return $mailWasSent;
[/SNIPPET]

Thanks for your advice.
Best,
Simon