App\Libraries\SettingDotEnv::setSettingFromEnv PHP Method

    public static function setSettingFromEnv($key, $value = null)
    {
        $cnt = 0;
        list($key, $value) = static::normaliseEnvironmentVariable($key, $value);
        // Filter out some Laravel system or dangerous environment variables
        // They all use the '_' as a word separator.
        $underPos = strpos($key, '_');
        if ($underPos > 0) {
            switch (substr($key, 0, $underPos)) {
                case "APP":
                case "DB":
                case "CACHE":
                case "MAIL":
                case "QUEUE":
                case "SESSION":
                    return $cnt;
            }
        }
        if (Setting::has($key)) {
            return $cnt;
        } else {
            Setting::set($key, $value);
            $cnt = 1;
        }
        return $cnt;
    }