curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer
chmod +x /usr/local/bin/composer

<?php
// 全局中间件定义文件
return [
    // 全局请求缓存
    // \think\middleware\CheckRequestCache::class,
    // 多语言加载
     \think\middleware\LoadLangPack::class,
    // Session初始化
    // \think\middleware\SessionInit::class
];

public function handle($request, Closure $next)
{
    // 自动侦测当前语言
    $langset = $this->detect($request);

    if ($this->lang->defaultLangSet() != $langset) {
        $this->lang->switchLangSet($langset);
    }

    $this->saveToCookie($this->app->cookie, $langset);

    return $next($request);
}

protected function detect(Request $request): string
{
    // 自动侦测设置获取语言选择
    $langSet = '';

    if ($request->get($this->config['detect_var'])) {
        // url中设置了语言变量
        $langSet = strtolower($request->get($this->config['detect_var']));
    } elseif ($request->header($this->config['header_var'])) {
        // Header中设置了语言变量
        $langSet = strtolower($request->header($this->config['header_var']));
    } elseif ($request->cookie($this->config['cookie_var'])) {
        // Cookie中设置了语言变量
        $langSet = strtolower($request->cookie($this->config['cookie_var']));
    } elseif ($request->server('HTTP_ACCEPT_LANGUAGE')) {
        // 自动侦测浏览器语言
        $match = preg_match('/^([a-z\d\-]+)/i', $request->server('HTTP_ACCEPT_LANGUAGE'), $matches);
        if ($match) {
            $langSet = strtolower($matches[1]);
            if (isset($this->config['accept_language'][$langSet])) {
                $langSet = $this->config['accept_language'][$langSet];
            }
        }
    }

    if (empty($this->config['allow_lang_list']) || in_array($langSet, $this->config['allow_lang_list'])) {
        // 合法的语言
        $range = $langSet;
        $this->lang->setLangSet($range);
    } else {
        $range = $this->lang->getLangSet();
    }

    return $range;
}

public function switchLangSet(string $langset)
{
    if (empty($langset)) {
        return;
    }

    $this->setLangSet($langset);

    // 加载系统语言包
    $this->load([
        $this->app->getThinkPath() . 'lang' . DIRECTORY_SEPARATOR . $langset . '.php',
    ]);

    // 加载系统语言包
    $files = glob($this->app->getAppPath() . 'lang' . DIRECTORY_SEPARATOR . $langset . '.*');
    $this->load($files);

    // 加载扩展（自定义）语言包
    $list = $this->app->config->get('lang.extend_list', []);

    if (isset($list[$langset])) {
        $this->load($list[$langset]);
    }
}

public function load($file, $range = ''): array
{
    $range = $range ?: $this->range;
    if (!isset($this->lang[$range])) {
        $this->lang[$range] = [];
    }

    $lang = [];

    foreach ((array) $file as $name) {
        if (is_file($name)) {
            $result = $this->parse($name);
            $lang   = array_change_key_case($result) + $lang;
        }
    }

    if (!empty($lang)) {
        $this->lang[$range] = $lang + $this->lang[$range];
    }

    return $this->lang[$range];
}

protected function parse(string $file): array
{
    $type = pathinfo($file, PATHINFO_EXTENSION);

    switch ($type) {
        case 'php':
            $result = include $file;
            break;
        case 'yml':
        case 'yaml':
            if (function_exists('yaml_parse_file')) {
                $result = yaml_parse_file($file);
            }
            break;
        case 'json':
            $data = file_get_contents($file);

            if (false !== $data) {
                $data = json_decode($data, true);

                if (json_last_error() === JSON_ERROR_NONE) {
                    $result = $data;
                }
            }

            break;
    }

    return isset($result) && is_array($result) ? $result : [];
}

<?php
error_reporting(0);
var_dump($_SERVER['argv']);