public static function env()
{
return function () {
// Use credentials from environment variables, if available
$key = getenv(self::ENV_KEY);
$secret = getenv(self::ENV_SECRET);
if ($key && $secret) {
return Promise\promise_for(new Credentials($key, $secret, getenv(self::ENV_SESSION)));
}
return self::reject('Could not find environment variable ' . 'credentials in ' . self::ENV_KEY . '/' . self::ENV_SECRET);
};
}