我刚刚用自己的设置安装了一个新的slim via composer。非常简单的index.php，里面很少：

<?php

use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ServerRequestInterface as Request;
use Slim\Factory\AppFactory;

require_once __DIR__ . '/../bootstrap.php';

// start the app
$APP = AppFactory::create();

/**
 * Middleware to check validation before any routes
 */
$APP->add(function(Request $request, Response $response, callable $next){

    $response = $next($request,$response);

    return $response;

});

/**
 * Add routes
 */
$APP->get('/test',function(Request $request, Response $response, array $args){

    return $response->getBody()->write('hello');
});

// run the app
$APP->run();

字符串
Php出现了一个奇怪的错误：

**致命错误：未捕获的类型错误：参数2传递到{闭包}（）必须是Psr\Http\Message\ResponseInterface的示例，给定的Slim\Routing\RouteRunner的示例，在/var/www/vendor/slim/slim/Slim/MiddlewareDispatcher. php第275行调用，并在/var/www/public/index.php中定义：16堆栈跟踪：#0 /var/www/vendor/slim/slim/Slim/MiddlewareDispatcher.php（275）：{close}（Object（Slim\Psr7\Request），Object（Slim\Routing\RouteRunner））

1 /var/www/vendor/slim/slim/Slim/MiddlewareDispatcher.php（73）：class@anonymous->handle（Object（Slim\Psr7\Request））#2

/var/www/vendor/slim/slim/Slim/App.php（206）：Slim\MiddlewareDispatcher->handle（Object（Slim\Psr7\Request））#3 /var/www/vendor/slim/Slim/App.php（190）：Copyright © 2018 - 2019 www.slive.com All Rights Reserved版权所有Slim\App->run（）#5 {main}抛出/var/www/public/index. php上线16**
我不明白为什么它说这里的基本中间件是采用Slim\Routing\RouteRunner的示例，而我明明给它的是Psr\Http\Message\ResponseInterface
你知道吗？
编辑：
感谢delboy的回答，但你能更具体一点吗？slim文档展示了如何像这样使用它（http://www.slimframework.com/docs/v3/concepts/middleware.html）：

$app->add(function ($request, $response, $next) {
    $response->getBody()->write('BEFORE');
    $response = $next($request, $response);
    $response->getBody()->write('AFTER');

    return $response;
});

型
但这不管用！总是得到类型错误，那么他们的文档是不是过时了？如果是这样，我如何在这里实现中间件？
他们给予的这个示例代码还产生了另一个奇怪的错误：

Fatal error: Uncaught ArgumentCountError: Too few arguments to function {closure}(), 2 passed in /var/www/vendor/slim/slim/Slim/MiddlewareDispatcher.php on line 275 and exactly 3 expected in /var/www/public/index.php:26 Stack trace: #0 /var/www/vendor/slim/slim/Slim/MiddlewareDispatcher.php(275): {closure}(Object(Slim\Psr7\Request), Object(class@anonymous)) #1 /var/www/vendor/slim/slim/Slim/MiddlewareDispatcher.php(73): class@anonymous->handle(Object(Slim\Psr7\Request)) #2 /var/www/vendor/slim/slim/Slim/App.php(206): Slim\MiddlewareDispatcher->handle(Object(Slim\Psr7\Request)) #3 /var/www/vendor/slim/slim/Slim/App.php(190): Slim\App->handle(Object(Slim\Psr7\Request)) #4 /var/www/public/index.php(38): Slim\App->run() #5 {main} thrown in /var/www/public/index.php on line 26

型
示例代码传递了3个参数，而不是2个！
编辑：
好了，Slim文档显然已经过时了，应该这样做：

$app->add(function(ServerRequestInterface $request, RequestHandlerInterface $handler) {

    $response = new Response();
    $response->getBody()->write('STUFF');

    return $response;
});

型