Sending emails with Silex Bootstrap (http://github.com/lucasmezencio/silex-bootstrap) and Swiftmailer + Twig

app.php

<?php

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

$app = require __DIR__.'/bootstrap.php';

$app->match('/contact/', function(Request $request) use ($app) {
    if ('POST' == $request->getMethod()) {
        $data = array(
            'nome'  => $request->get('name'),
            'email' => $request->get('email')
        );

        $message = $app['mailer']
            ->createMessage()
            ->setSubject('Subject')
            ->setFrom(array($request->get('email')))
            ->setTo(array('[email protected]'))
            ->setBody($app['twig']->render('email.html.twig', $data), 'text/html');

        $app['mailer']->send($message);

        if ($request->isXmlHttpRequest()) {
            return $app->json(array(
                'status' => true
            ));
        }
    }

    return $app['twig']->render('contact.html.twig');
})->bind('contact');

return $app;

bootstrap.php

<?php

require_once __DIR__.'/../vendor/autoload.php';

use Silex\Provider\TwigServiceProvider;
use Silex\Provider\SwiftmailerServiceProvider;

$env = getenv('APPLICATION_ENV') ? getenv('APPLICATION_ENV') : 'production';
$ini_config = parse_ini_file(__DIR__.'/config.ini', TRUE);
$config = $ini_config[$env];

$app = new Silex\Application();

$app->register(new TwigServiceProvider(), array(
    'twig.path' => __DIR__.'/templates',
    'twig.options' => array('cache' => __DIR__.'/../cache'),
));

$app->register(new SwiftmailerServiceProvider(), array(
    'swiftmailer.options' => array(
        'host'       => $config['mail.host']
        'port'       => $config['mail.port']
        'username'   => $config['mail.username']
        'password'   => $config['mail.password']
        'encryption' => $config['mail.encryption']
        'auth_mode'  => $config['mail.auth_mode']
    )
));

return $app;

config.ini

[production]
db.driver       = pdo_mysql
db.dbname       = dumb
db.host         = localhost
db.user         = root
db.password     = root
mail.host       = localhost
mail.port       = 123
mail.username   = username
mail.password   = password
mail.encryption = ssl
mail.auth_mode  = login

[staging]
db.driver       = pdo_mysql
db.dbname       = dumb
db.host         = localhost
db.user         = root
db.password     = root
mail.host       = localhost
mail.port       = 123
mail.username   = username
mail.password   = password
mail.encryption = ssl
mail.auth_mode  = login

[development]
db.driver       = pdo_mysql
db.dbname       = dumb
db.host         = localhost
db.user         = root
db.password     = root
mail.host       = localhost
mail.port       = 123
mail.username   = username
mail.password   = password
mail.encryption = ssl
mail.auth_mode  = login

index.php

<?php

$app = require __DIR__.'/../src/app.php';

$app->run();

No trecho

$app->match('/contact/', function() { ... });

você tem dois níveis de identação. Dá pra melhorar.