Combine SMTP and Mimemail modules?

Just like you, I have been searching around for a solution for close to a month (on and off).

Not being able to find one, I decided to start reading the code and trying to understand what's happening.

Please note that I have never programmed PHP before. All I did is copy/paste and read a bit about arrays on PHP's website.

My site is running with Drupal 5. You can check it out at www.bp2x.com.

Here's what you need to do:
1. disable the drupal_mail_wrapper() from mimemail

if (strpos(variable_get('smtp_library', ''), 'mimemail')
  && !function_exists('drupal_mail_wrapper')) {
/*
  function drupal_mail_wrapper($mailkey, $to, $subject, $body, $from, $headers) {
    return mimemail($from, $to, $subject, $body, null, $headers);
  }
  */
}

2. rename drupal_mail_wrapper() function drupal_mail_wrapper($mailkey, $to, $subject, $body, $from, $header) { from the smtp module to internal_drupal_mail_wrapper()

function internal_drupal_mail_wrapper($mailkey, $to, $subject, $body, $from, $header) {

3. create a new drupal_mail_wrapper() for the smtp module with the following code

function drupal_mail_wrapper($mailkey, $to, $subject, $body, $from, $header) {

	$message = mimemail_prepare($from, $to, $subject, $body, false, $header);
	
	$status = true;

	if (is_array($message['address'])) {
		foreach ($message['address'] as $a) {
	        $status = internal_drupal_mail_wrapper('mimemail',
	          $a,
	          $message['subject'],
	          $message['body'],
			  $mnessage['sender'],
	          $message['headers']
	        ) && $status;
	    
	    }
	}
	else {
		$status = internal_drupal_mail_wrapper('mimemail',
	          $message['address'],
	          $message['subject'],
	          $message['body'],
			  $mnessage['sender'],
	          $message['headers']
	        ) && $status;
	}
	  
	  return $status;
}

That's it.

I tested it with simplenews, creating an account, and sending a new password for an existing account. They all work fine.

Further testing revealed a problem with sending HTML messages from simplenews. It was working because mimemail was sending the messages through teh PHP mail function and not using the overriden smtp mail function. So I made the following modifications.

4. Create a new function in smtp module (see code below)

function smtpmail($sender, $recipient, $subject, $body, $plaintext=null, $headers=array(), $text=null, $attachments=array()) {

	$header['Content-Type'] = 'text/html';
	
	$sender = variable_get('site_mail', ini_get('sendmail_from'));
	
	return internal_drupal_mail_wrapper('smtpmail', $recipient, $subject, $body, $sender, $header);
}

5. Modify simplenews.module, comment calling mimemail and add a call to the smtpmail function we created above.

    return smtpmail($from, $mail->to, $mail->subject, $mail->body, $plain_text_only, $headers, $plain_text_body);
    //return mimemail($from, $mail->to, $mail->subject, $mail->body, $plain_text_only, $headers, $plain_text_body);

6. Add a new condition to the smtp.module in the function

function internal_drupal_mail_wrapper($mailkey, $to, $subject, $body, $from, $header) {

after the lines

    else { //Else the header key is not special, just add it.
      $mail->AddCustomHeader($key . ": " . $value); //Add header line.
    }
  }

The new code added is:

  if ($mailkey == 'mimemail')
  {
	$mail->message_type = "pre";
  }

This tells the SMTP module not to format the email message body, since it is already mime encoded by the mimemail module.

And then I ticked the "Use mime mail for all messages" option in "Home » Administer » Site configuration » Mail".

It's a bloody dirty hack but at least now I can send html newsletters to my users again.