PHP Slim 3 中间件的不合理错误

Question

I am trying to use the ValidationErrorsMiddleware.php class as a middleware, so I added the following code to my bootstrap/app.php:

$app->add(new App\Middleware\ValidationErrorsMiddleware($container));

I got the following errors after the above code is added to my app.php:

Fatal error: Uncaught exception 'RuntimeException' with message 'Unexpected data in output buffer. Maybe you have characters before an opening <?php tag?' in C:\wamp64\www\authentication\vendor\slim\slim\Slim\App.php on line 552
RuntimeException: Unexpected data in output buffer. Maybe you have characters before an opening <?php tag? in C:\wamp64\www\authentication\vendor\slim\slim\Slim\App.php on line 552

Just in case, anyone needs to look at the code of my classes and app.php, I have included them down here

---

ValidationErrorsMiddleware.php

<?php

namespace App\Middleware;

class ValidationErrorsMiddleware extends Middleware {

  public function __invoke($request, $response, $next) {

    var_dump('middleware');
    $response = $next($request, $response);

    return $response;
  }
}

Middleware.php

<?php

namespace App\Middleware;

class Middleware {

protected $container;

  public function __construct($container) {

    $this->container = $container;
  }
}

App.php

<?php

session_start();

require __DIR__ . '/../vendor/autoload.php';

$app = new \Slim\App([
'settings' => [
    'determineRouteBeforeAppMiddleware' => false,
    'displayErrorDetails' => true,
    'db' => [
        // Eloquent configuration
        'driver' => 'mysql',
        'host' => 'localhost',
        'database' => 'phpdb',
        'username' => 'root',
        'password' => 'root',
        'charset' => 'utf8',
        'collation' => 'utf8_unicode_ci',
        'prefix' => '',
    ]
],
]);


$container = $app->getContainer();

$app->add(new App\Middleware\ValidationErrorsMiddleware($container));

require __DIR__ . '/../app/routes.php';

Answer 1

I've fixed my problem doing this:

return [
'settings' => [
    // Slim Settings
    'determineRouteBeforeAppMiddleware' => true,
    'displayErrorDetails' => true,
    'addContentLengthHeader' => false,

I added the attribute addContentLengthHeader with the value false in the settings array.

But I still did not understand what this is for

UPDATE

This problem happens because of the line var_dump(middleware) thats changes the content length of the response. My solution was just a hack. Thanks to @iKlsR for the right answer.

Answer 2

Setting addContentLengthHeader to false is not a proper fix and can lead to woes later on when your app gets larger. Your problem is the var_dump('middleware'); which you are printing before you return the response. This makes the size of your Content-Length header incorrect, thus the error, since there are characters outside of this. php should also hint at this by letting you know something about unexpected data if you have error reporting on.

To test or modify your middleware with statements, edit the response body with $response->getBody()->write('message'); tho a simple die('message'); should be good enough to see if it was hit.

Answer 3

I had the same problem because I called the $app->run(); statement twice. I just deleted one of them and everything worked well (keeping: addContentLengthHeader as true ).

Answer 4

I had the same issue with the given tutorial, the Fatal error is produced by this line:

$this->container->view->getEnvironment()->addGlobal('errors', $_SESSION['errors']);
unset($_SESSION['errors']);

the $_SESSION['errors'] on boot is not set and in this case we receive a Notice which causes a Fatal Error

what I made, I check on boot if $_SESSION['errors'] is set

if(isset($_SESSION['errors'])) {
        $this->container->view->getEnvironment()->addGlobal('errors', $_SESSION['errors']);
    }

    unset($_SESSION['errors']);

Answer 5

它实际上是一个与缓冲相关的缓冲区问题，要么通过进入“ php.ini ”文件来关闭缓冲区，要么在脚本的开头简单地使用ob_end_clean() ...

Answer 6

In my case I had a double $app->run(); code.

Answer 7

如果对于某人上述所有解决方案都不起作用，您将需要检查您包含的任何文件是否未编码为UTF8-Bom （或任何格式的 Bom），这里的答案有助于修复问题，如果您选择正确的格式，也可以通过 vscode 完成

Answer 8

only you've edit the next in your index:

$app = new \Slim\App([
    'settings' => [
        'addContentLengthHeader' => false
    ]
]);