emails/api/resources/routes/02_attachments.php

<?php
use ProVM\Common\Controller\Attachments;

$app->group('/attachments', function($app) {
    $app->put('/grab', [Attachments::class, 'grab']);
    $app->post('/decrypt', [Attachments::class, 'decrypt']);
    $app->get('[/]', Attachments::class);
});
$app->group('/attachment/{attachment_id}', function($app) {
    $app->get('[/]', [Attachments::class, 'get']);
});