Email Attachments in Magento 2.4.8

[fmaniconereply]

Preconditions and environment

• Magento version 2.4.8

Could you explain the rationale behind having the EmailMessage class extend the Message class, rather than a class directly related to email sending, such as Mail? Additionally, since the Message class does not provide methods like attach to handle attachments, how does Magento handle email attachments in this architecture?

Steps to reproduce

Create a script for send email
use method "attach" to add attachment

Expected result

It is not possible to add an attachment.

Actual result

It is not possible to add an attachment.

Additional information

No response

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[fmaniconereply]

A really messy solution is to do this to add an attachment:

$message = $transport->getMessage();
$symfonyEmail = $message->getSymfonyMessage();
if (!$symfonyEmail instanceof Email) {
    // Manually recreate an Email from Message
    $email = new Email();

    foreach ($symfonyEmail->getHeaders()->all() as $header) {
        $email->getHeaders()->add($header);
    }

    $email->html($symfonyEmail->getBody()->getBody());

    $emailMessage = $email;
}
$emailMessage->attach(
    $attachmentContent,
    'invoice_' . $order->getIncrementId() . '.pdf',
    'application/pdf'
);
$message->setBody($emailMessage);
$transport->sendMessage();

[m2-assistant]

Hi @engcom-November. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

• 1. Verify that issue has all the required information. (Preconditions, Steps to reproduce, Expected result, Actual result).
• 2. Verify that issue has a meaningful description and provides enough information to reproduce the issue.
• 3. Add Area: XXXXX label to the ticket, indicating the functional areas it may be related to.
• 4. Verify that the issue is reproducible on 2.4-develop branch
  Details

  - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
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[Silarn]

I would note that the MimePartInterface / MimeMessageInterface classes used to handle this properly but it no longer handles multi-part MimeParts.

In \Magento\Framework\Mail\MimePart it does correctly create the 'parts':

            if ($type === MimeInterface::TYPE_HTML) {
                $this->mimePart = new TextPart($content, $charset, 'html', $encoding);
            } elseif ($type === MimeInterface::TYPE_TEXT) {
                $this->mimePart = new TextPart($content, $charset, 'plain', $encoding);
            } else {
                $this->mimePart = new DataPart($content, $fileName, $type, $encoding);
            }

However, when this is converted to an actual Symfony message, only the first TextPart is used and the rest are discarded.

In \Magento\Framework\Mail\MimeMessage:

    public function __construct(array $parts)
    {
        $headers = null;
        $body = null;

        foreach ($parts as $part) {
            $mimePart = $part->getMimePart();
            if ($mimePart instanceof TextPart) {
                $headers = $mimePart->getHeaders();
                $body = $mimePart;
                break;
            }
        }

        $this->mimeMessage = new Message($headers, $body);
    }

As you can see, any TextPart types are inserted into the body and the remaining parts are discarded. Technically this does include DataPart attachments but it'll only process the first part.

To properly merge all of the parts we need to do something a bit more like the Symfony Mailer class:

    public function __construct(array $parts)
    {
        $dataParts = [];
        $headers = new Headers();
        $html = null;
        $text = null;
        /** @var MimePartInterface $part */
        foreach ($parts as $part) {
            $headers = new Headers(...$headers->all(), ...$mimePart->getHeaders()->all());
            $mimePart = $part->getMimePart();
            if ($mimePart instanceof TextPart) {
                if ($mimePart->getMediaSubtype() == 'html') {
                    $html = $mimePart;
                } elseif ($mimePart->getMediaSubtype() == 'plain') {
                    $text = $mimePart;
                } else {
                    $dataParts[] = $mimePart;
                }
            }
        }
        
        if ($html && $text) {
            $body = new AlternativePart($text, $html);
        } else if ($html) {
            $body = $html;
        } else if ($text) {
            $body = $text;
        }
        
        if ($dataParts) {
            $body = new MixedPart($body, ...$dataParts);
        }
        $this->mimeMessage = new Message($headers, $body);
    }

[Silarn]

I'm actually not sure that we need to include the Symfony Part headers in the Message $headers... unless we need to add additional headers to the email I'm fairly sure the Part headers will be included automatically.

Just passing in an empty Headers() may be fine.

[Silarn]

A really messy solution is to do this to add an attachment:

$message = $transport->getMessage();
$symfonyEmail = $message->getSymfonyMessage();
if (!$symfonyEmail instanceof Email) {
    // Manually recreate an Email from Message
    $email = new Email();

    foreach ($symfonyEmail->getHeaders()->all() as $header) {
        $email->getHeaders()->add($header);
    }

    $email->html($symfonyEmail->getBody()->getBody());

    $emailMessage = $email;
}
$emailMessage->attach(
    $attachmentContent,
    'invoice_' . $order->getIncrementId() . '.pdf',
    'application/pdf'
);
$message->setBody($emailMessage);
$transport->sendMessage();

A slightly less hacky way is to simply make use of the Symfony MixedPart:

$symfonyMessage = $message->getSymfonyMessage();
$attachment = new DataPart($attachmentContent, 'invoice_' . $order->getIncrementId() . '.pdf', 'application/octet-stream', 'base64');
$symfonyMessage->setBody(new MixedPart($symfonyMessage->getBody(), $attachment));

[Silarn]

Some of the other implementations in MimeMessage also look off:

 public function isMultiPart(): bool
    {
        $body = $this->mimeMessage->getBody();
        return $body instanceof AlternativePart && $body->countParts() > 1;
    }

This probably needs to check for AbstractMultipartPart rather than AlternativePart as it is the parent class of AlternativePart, MixedPart, DigestPart, etc. In addition, I don't see a 'countParts()' function, so I think this is going to fail. Probably needs to be count($body->getParts()).

Same for the getParts() function, it should check for AbstractMultipartPart rather than AlternativePart.

[m2-assistant]

Hi @engcom-Hotel. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

• 1. Verify that issue has all the required information. (Preconditions, Steps to reproduce, Expected result, Actual result).
• 2. Verify that issue has a meaningful description and provides enough information to reproduce the issue.
• 3. Add Area: XXXXX label to the ticket, indicating the functional areas it may be related to.
• 4. Verify that the issue is reproducible on 2.4-develop branch
  Details

  - If the issue is reproducible on 2.4-develop branch, please, add the label Reproduced on 2.4.x.
  - If the issue is not reproducible, add your comment that issue is not reproducible and close the issue and stop verification process here!
• 5. Add label Issue: Confirmed once verification is complete.
• 6. Make sure that automatic system confirms that report has been added to the backlog.

[engcom-Hotel]

Hello @fmaniconereply,

Thanks for the report and collaboration!

Yes its true there is no straight way for attaching file in the mails in Magento core. Hence confirming this issue.

Thanks

[github-jira-sync-bot]

✅ Jira issue https://jira.corp.adobe.com/browse/AC-14581 is successfully created for this GitHub issue.

[m2-assistant]

✅ Confirmed by @engcom-Hotel. Thank you for verifying the issue.
Issue Available: @engcom-Hotel, You will be automatically unassigned. Contributors/Maintainers can claim this issue to continue. To reclaim and continue work, reassign the ticket to yourself.

[hostep]

We did have a PR at one time that introduced this email attachment feature request, but for some lame reason it got rejected by internal Adobe devs. Maybe we can try again if they are willing, maybe @engcom-Hotel can first double check internally if Adobe devs are open for this feature this time?

[Silarn]

@hostep Not sure if this had anything to do with the switch to Symfony (which was most definitely BIC) but the above MimeMessage changes would be necessary for that PR to function as well.