中间件
最后更新于：2022-04-02 07:05:53
## 中间件
中间件主要用于拦截或过滤应用的请求，并进行必要的业务处理，通常使用在登录验证的场景，基于 [PSR-15](https://www.php-fig.org/psr/psr-15/) 标准实现。
## 组件
使用 [composer]([https://www.phpcomposer.com/](https://www.phpcomposer.com/)) 安装：
~~~
composer require mix/http-server
~~~
## 定义中间件
~~~
*/
class AuthMiddleware implements MiddlewareInterface
{
/**
* @var ServerRequest
*/
public $request;
/**
* @var Response
*/
public $response;
/**
* @var Authorization
*/
public $auth;
/**
* SessionMiddleware constructor.
* @param ServerRequest $request
* @param Response $response
*/
public function __construct(ServerRequest $request, Response $response)
{
$this->request = $request;
$this->response = $response;
$this->auth = context()->get('auth');
}
/**
* Process an incoming server request.
*
* Processes an incoming server request in order to produce a response.
* If unable to produce the response itself, it may delegate to the provided
* request handler to do so.
*/
public function process(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface
{
// 权限验证
$tokenExtractor = new BearerTokenExtractor($request);
try {
$payload = $this->auth->getPayload($tokenExtractor);
} catch (\Throwable $e) {
// 中断执行，返回错误信息
$content = ['code' => 100001, 'message' => 'No access'];
$response = ResponseHelper::json($this->response, $content);
return $response;
}
// 把 JWT Payload 放入 Request 的上下文，方便其他位置调用
$context = $this->request->getContext();
$context->payload = $payload;
// 继续往下执行
return $handler->handle($request);
}
}
~~~
## 注册中间件
定义的中间件需要在路由规则 `middleware` 字段中注册：
```
// 路由规则
'rules' => [
// 普通路由
'/' => [[\App\Http\Controllers\IndexController::class, 'index'], 'middleware' => [\App\Http\Middleware\ActionMiddleware::class]],
],
],
```
### 全局中间件
全局中间件是全局有效的：
~~~
// 路由
[
// 名称
'name' => 'route',
// 类路径
'class' => \Mix\Route\Router::class,
// 初始化方法
'initMethod' => 'parse',
// 属性注入
'properties' => [
...
// 全局中间件
'middleware' => [\App\Http\Middleware\GlobalMiddleware::class],
// 路由规则
'rules' => [
...
],
],
],
~~~
### 分组中间件
分组中间件只在该路由分组的规则中有效：
~~~
// 路由
[
// 名称
'name' => 'route',
// 类路径
'class' => \Mix\Route\Router::class,
// 初始化方法
'initMethod' => 'parse',
// 属性注入
'properties' => [
...
// 路由规则
'rules' => [
...
// 分组路由
'/v2' => [
// 分组中间件
'middleware' => [\App\Http\Middleware\GroupMiddleware::class],
// 分组路由规则
'rules' => [
...
],
],
],
],
],
~~~
框架骨架代码中默认包含了几个常用中间件：
- [AuthMiddleware.php](https://github.com/mix-php/mix-skeleton/tree/v2.1/app/Api/Middleware/AuthMiddleware.php "AuthMiddleware.php")
- [SessionMiddleware.php](https://github.com/mix-php/mix-skeleton/tree/v2.1/app/Web/Middleware/SessionMiddleware.php "SessionMiddleware.php")
- [CorsMiddleware.php](https://github.com/mix-php/mix-skeleton/tree/v2.1/app/Api/Middleware/CorsMiddleware.php "CorsMiddleware.php")
';