think\Session::init PHP Method

    public static function init(array $config = [])
    {
        if (empty($config)) {
            $config = Config::get('session');
        }
        // 记录初始化信息
        App::$debug && Log::record('[ SESSION ] INIT ' . var_export($config, true), 'info');
        $isDoStart = false;
        if (isset($config['use_trans_sid'])) {
            ini_set('session.use_trans_sid', $config['use_trans_sid'] ? 1 : 0);
        }
        // 启动session
        if (!empty($config['auto_start']) && PHP_SESSION_ACTIVE != session_status()) {
            ini_set('session.auto_start', 0);
            $isDoStart = true;
        }
        if (isset($config['prefix'])) {
            self::$prefix = $config['prefix'];
        }
        if (isset($config['var_session_id']) && isset($_REQUEST[$config['var_session_id']])) {
            session_id($_REQUEST[$config['var_session_id']]);
        } elseif (isset($config['id']) && !empty($config['id'])) {
            session_id($config['id']);
        }
        if (isset($config['name'])) {
            session_name($config['name']);
        }
        if (isset($config['path'])) {
            session_save_path($config['path']);
        }
        if (isset($config['domain'])) {
            ini_set('session.cookie_domain', $config['domain']);
        }
        if (isset($config['expire'])) {
            ini_set('session.gc_maxlifetime', $config['expire']);
            ini_set('session.cookie_lifetime', $config['expire']);
        }
        if (isset($config['use_cookies'])) {
            ini_set('session.use_cookies', $config['use_cookies'] ? 1 : 0);
        }
        if (isset($config['cache_limiter'])) {
            session_cache_limiter($config['cache_limiter']);
        }
        if (isset($config['cache_expire'])) {
            session_cache_expire($config['cache_expire']);
        }
        if (!empty($config['type'])) {
            // 读取session驱动
            $class = false !== strpos($config['type'], '\\') ? $config['type'] : '\\think\\session\\driver\\' . ucwords($config['type']);
            // 检查驱动类
            if (!class_exists($class) || !session_set_save_handler(new $class($config))) {
                throw new ClassNotFoundException('error session handler:' . $class, $class);
            }
        }
        if ($isDoStart) {
            session_start();
            self::$init = true;
        } else {
            self::$init = false;
        }
    }

function session($name, $value = '')
{
    if (is_array($name)) {
        // 初始化
        \think\Session::init($name);
    } elseif (is_null($name)) {
        // 清除
        \think\Session::clear($value);
    } elseif ('' === $value) {
        // 获取
        return \think\Session::get($name);
    } elseif (is_null($value)) {
        // 删除session
        return \think\Session::delete($name);
    } else {
        // 设置session
        return \think\Session::set($name, $value);
    }
}