Make it possible to have separate email templates for html and plain-text

[RafaelKr]

Q	A
Bug?	no
New Feature?	yes
Community Bundle Version	^2.0@dev, 17e2867
Sulu Version	2.6.5
Browser Version	-

Actual Behavior

Currently we can only define one email template per type (registration, email confirmation, ...).

If you use an HTML template Symfony will automatically generate a text version based on the following rules:
https://symfony.com/doc/current/mailer.html#text-content

When you have an advanced template with a footer with a lot of information this has the downside, that probably the indentation is completely off. Also sometimes we just want to have a different templates for html and text.

Expected Behavior

It would be good to be able to define two separate templates.

Steps to Reproduce

Possible Solutions

Maybe we could have user_template and admin_template and additionally user_template_plain and admin_template_plain.

Or, my preferred option, we define it like user_template: community/email-confirmation-email and it will automatically try to find community/email-confirmation-email.html.twig and community/email-confirmation-email.txt.twig.
Also see: https://symfony.com/doc/current/mailer.html#text-content

I'm open to create a PR for my preferred approach.

Btw instead of new Email we could also use new TemplatedEmail.

[RafaelKr]

The implementation we use in our project now:

config/packages/sulu_community.yaml

sulu_community:
  webspaces:
    website:
      # ...

      registration:
        # ...
        email:
          subject: Registration
          # note there's no extension, it will load:
          # portal/email/auth/registration-email.html.twig as htmlTemplate
          # portal/email/auth/registration-email.txt.twig as textTemplate
          user_template: portal/email/auth/registration-email
          admin_template: ~

config/services.yaml

services:
  # ...

  App\DependencyInjection\SuluCommunityBundle\Mail\MailFactory:
    decorates: sulu_community.mail_factory
    parent: sulu_community.mail_factory

/src/DependencyInjection/SuluCommunityBundle/Mail/MailFactory.php

<?php

declare(strict_types=1);

namespace App\DependencyInjection\SuluCommunityBundle\Mail;

use Sulu\Bundle\CommunityBundle\Mail\MailFactory as BaseMailFactory;
use Symfony\Bridge\Twig\Mime\TemplatedEmail;

/*
 * Decorates sulu_community.mail_factory
 *
 * This allows us to have separate templates for plain text and html
 * See: https://github.com/sulu/SuluCommunityBundle/discussions/177
 */
class MailFactory extends BaseMailFactory
{
    protected function sendEmail($from, $to, string $subject, string $template, array $data): void
    {
        if (!$this->getAddress($from) || !$this->getAddress($to)) {
            return;
        }

        $email = (new TemplatedEmail())
            ->context($data)
            ->subject($this->translator->trans($subject))
            ->from($this->getAddress($from))
            ->to($this->getAddress($to))
            ->htmlTemplate($this->templatePath($template, 'html'))
            ->textTemplate($this->templatePath($template, 'txt'));

        $this->mailer->send($email);
    }

    protected function templatePath(string $templateBasePath, string $extension): string
    {
        return \sprintf(
            '%s.%s.twig',
            $templateBasePath,
            $extension,
        );
    }
}