Change Email Driver inside Mailable

Hi all,

I've written a Transport driver for SendGrid. Very simple. It's a fully working driver, that I set up by extending swift.transport. Like so :

$this->app['swift.transport']->extend('sendgrid', function ($app) {
            $config = $this->app['config']->get('services.sendgrid', []);

            $httpclient = new \GuzzleHttp\Client(
                Arr::add($config['guzzle'] ?? [], 'connect_timeout', 60)
            );

            return new \App\Mail\Transport\SendGridTransport(
                $httpclient,
                $config['secret'],
                $config['endpoint'] ?? null
            );
        });

Tested it and everything works beautifully. However, there are many locations across my app that I _don't _ want to use SendGrid. I don't want production based dev emails going through SendGrid. It's a waste of the quota.

Rather than finding every single location I do Mail:to()->send(new MyEmailMailable()); is it possible to change the driver on the Mailable object itself?

I was thinking maybe a trait that overrides send() and just changes the driver. I can't seem to figure out how to do it though. Any ideas?

simonw

6 years ago

Level 1

To add to this, understandably a Mailable shouldn't really know about it's Transport, but it does take a mailer object in send, so it seemed as good as any: send(MailerContract $mailer).

Another option could be to create a 3rd Transport class which acts as a Transport router. I could have that class delegate to any of the other drivers as I wish. This might be more favourable, but if my first option is doable that might be quicker for now.

simonw

6 years ago

Level 1

No answer so here is my solution. Others may find this useful.

Use ->extend as above to create a custom Transport driver. Make this driver act as a resolver. When ->send() is called, resolve the transport property and delegate to the driver that you set.

Example:

/**
     * {@inheritdoc}
     */
    public function send(Swift_Mime_SimpleMessage $message, &$failedRecipients = null)
    {
        // forward this on to the declared transport (driver)
        return $this->transport->send($message, $failedRecipients);
    }

/**
     * Change the mail driver at run-time
     */
    public function setDriver($driver, $config = [])
    {
        if (is_string($driver) && $driver != 'smtp') {
            $driver = new $driver($this->client, $config['secret'], $config['endpoint'] ?? null);
            $this->transport = $driver;
        }

        // set to smtp driver
        if ($driver === 'smtp') {
            $this->transport = $this->createSmtpDriver();
        }

        if (!($this->transport instanceof \Swift_Transport)) {
            $name = get_class($this->transport);
            throw new \Swift_TransportException("$name not found or is not an instance of \Swift_Transport");
        }

        return $this;
    }

And, finally if I want a specific set of Mailable's to use a different transport (Maybe admin emails don't want to be run through SendGrid)

use App\Mail\Transport\SmtpDriver;

class AdminEmailError extends Mailable
{
    use Queueable, SerializesModels, SmtpDriver;
    
    ...
}

trait SmtpDriver
{
    /**
     * Send the message using the given mailer.
     *
     * @param  \Illuminate\Contracts\Mail\Mailer  $mailer
     * @return void
     */
    public function send(MailerContract $mailer)
    {
        // if we are using our custom Transport Router, set the driver to use smtp
        $transport = $mailer->getSwiftMailer()->getTransport();
        if (method_exists($transport, 'setDriver')) {
            $transport->setDriver('smtp');
        }

        parent::send($mailer);
    }
}

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