Mail sending with template using swift mailer in Symfony

Create new class named MailSender.

namespace MyBundle;

use Swift_Mailer;
use Swift_Message;
use Twig_Environment;

class MailSender
{
    /** @var Swift_Message */
    private $mailer;

    /** @var Twig_Environment */
    private $twig;

    /**
     * @param Swift_Mailer     $mailer
     * @param Twig_Environment $twig
     */
    public function __construct(Swift_Mailer $mailer, Twig_Environment $twig)
    {
        $this->mailer = $mailer;
        $this->twig = $twig;
    }

    /**
     * Prepare message to sent.
     *
     * @param string $to
     * @param string $subject
     * @param string $twig
     * @param array  $parameters
     *
     * @return Swift_Message
     */
    private function prepare($to, $subject, $twig, array $parameters)
    {
        return  Swift_Message::newInstance()
            ->setSubject($subject)
            ->setFrom('no-reply@galitein.com')
            ->setTo($to)
            ->setBody(
                $this->twig->render($twig, $parameters),
                'text/html'
            );
    }

    /**
     * @param string $to
     * @param string $subject
     * @param string $twig
     * @param array  $parameters
     *
     * @return bool
     */
    public function send($to, $subject, $twig, array $parameters)
    {
        $this->mailer->send($this->prepare($to, $subject, $twig, $parameters));

        return true;
    }
}

* Set parameters for swift mailer in config.yml

# Swiftmailer Configuration
swiftmailer:
    transport: "%mailer_transport%"
    host:      "%mailer_host%"
    username:  "%mailer_user%"
    password:  "%mailer_password%"
    spool:     { type: memory }

mailer details set in parameters.yml

* Register MailSender class as service in Services.yml

services:
    my_bundle.mail_sender:
        class: MyBundle\MailSender
        arguments:
            - '@mailer'
            - '@twig'

* Send mail from controller

$this->get('my_bundle.mail_sender') 

->send($email, 'Mail subject', 'Templates/contact.html.twig', [ 

 'contact_details' => $data, 

]);