Slim 框架提供了一个令人困惑的未捕获类型错误

Question

我刚刚使用我自己的设置通过 composer 安装了一个新的 slim 副本。非常简单的 index.php，里面的内容很少：

<?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();

PHP给出了一个非常奇怪的错误：

**致命错误：未捕获的类型错误：传递给 {closure}() 的参数 2 必须是 Psr\Http\Message\ResponseInterface 的实例，给出的 Slim\Routing\RouteRunner 实例，在 /var/www/vendor/slim/ 中调用slim/Slim/MiddlewareDispatcher.php 位于第 275 行，定义在 /var/www/public/index.php:16 堆栈跟踪：#0 /var/www/vendor/slim/slim/Slim/MiddlewareDispatcher.php(275)： {closure}（对象（Slim\Psr7\Request），对象（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/Slim /App.php(190): Slim\App->handle(Object(Slim\Psr7\Request)) #4 /var/www/public/index.php(34): Slim\App->run() #5 {main} 在第 16 行的 /var/www/public/index.php 中抛出**

我不明白为什么它说这里的基本中间件正在使用 Slim\Routing\RouteRunner 的实例，而我清楚地给了它 Psr\Http\Message\ResponseInterface

任何的想法？

编辑：

感谢delboy的回答，但你能更具体点吗？苗条的文档显示像这样使用它（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;
});

但这不起作用！总是得到类型错误，那么他们的文档是否过时了？如果是这样，我如何在这里实现中间件？

他们给出的这个示例代码也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

我的示例代码传递了 3 个参数，而不是 2 个！

编辑：

好吧，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;
});

Answer 1

您的中间件没有实现 PSR-15。您不应该传递响应，而是传递请求处理程序接口：

namespace Psr\Http\Server;

use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

/**
 * Participant in processing a server request and response.
 *
 * An HTTP middleware component participates in processing an HTTP message:
 * by acting on the request, generating the response, or forwarding the
 * request to a subsequent middleware and possibly acting on its response.
 */
interface MiddlewareInterface
{
    /**
     * 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;
}

https://www.php-fig.org/psr/psr-15/