<form method="POST">
    <h3>Editing: HttpKernelBrowser.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\HttpKernel;

use Symfony\Component\BrowserKit\AbstractBrowser;
use Symfony\Component\BrowserKit\CookieJar;
use Symfony\Component\BrowserKit\History;
use Symfony\Component\BrowserKit\Request as DomRequest;
use Symfony\Component\BrowserKit\Response as DomResponse;
use Symfony\Component\HttpFoundation\File\UploadedFile;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

/**
 * Simulates a browser and makes requests to an HttpKernel instance.
 *
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * @method Request  getRequest()
 * @method Response getResponse()
 */
class HttpKernelBrowser extends AbstractBrowser
{
    protected $kernel;
    private $catchExceptions = true;

    /**
     * @param array $server The server parameters (equivalent of $_SERVER)
     */
    public function __construct(HttpKernelInterface $kernel, array $server = [], ?History $history = null, ?CookieJar $cookieJar = null)
    {
        // These class properties must be set before calling the parent constructor, as it may depend on it.
        $this-&gt;kernel = $kernel;
        $this-&gt;followRedirects = false;

        parent::__construct($server, $history, $cookieJar);
    }

    /**
     * Sets whether to catch exceptions when the kernel is handling a request.
     */
    public function catchExceptions(bool $catchExceptions)
    {
        $this-&gt;catchExceptions = $catchExceptions;
    }

    /**
     * {@inheritdoc}
     *
     * @param Request $request
     *
     * @return Response
     */
    protected function doRequest(object $request)
    {
        $response = $this-&gt;kernel-&gt;handle($request, HttpKernelInterface::MAIN_REQUEST, $this-&gt;catchExceptions);

        if ($this-&gt;kernel instanceof TerminableInterface) {
            $this-&gt;kernel-&gt;terminate($request, $response);
        }

        return $response;
    }

    /**
     * {@inheritdoc}
     *
     * @param Request $request
     *
     * @return string
     */
    protected function getScript(object $request)
    {
        $kernel = var_export(serialize($this-&gt;kernel), true);
        $request = var_export(serialize($request), true);

        $errorReporting = error_reporting();

        $requires = '';
        foreach (get_declared_classes() as $class) {
            if (0 === strpos($class, 'ComposerAutoloaderInit')) {
                $r = new \ReflectionClass($class);
                $file = \dirname($r-&gt;getFileName(), 2).'/autoload.php';
                if (file_exists($file)) {
                    $requires .= 'require_once '.var_export($file, true).&quot;;\n&quot;;
                }
            }
        }

        if (!$requires) {
            throw new \RuntimeException('Composer autoloader not found.');
        }

        $code = &lt;&lt;&lt;EOF
&lt;?php

error_reporting($errorReporting);

$requires

\$kernel = unserialize($kernel);
\$request = unserialize($request);
EOF;

        return $code.$this-&gt;getHandleScript();
    }

    protected function getHandleScript()
    {
        return &lt;&lt;&lt;'EOF'
$response = $kernel-&gt;handle($request);

if ($kernel instanceof Symfony\Component\HttpKernel\TerminableInterface) {
    $kernel-&gt;terminate($request, $response);
}

echo serialize($response);
EOF;
    }

    /**
     * {@inheritdoc}
     *
     * @return Request
     */
    protected function filterRequest(DomRequest $request)
    {
        $httpRequest = Request::create($request-&gt;getUri(), $request-&gt;getMethod(), $request-&gt;getParameters(), $request-&gt;getCookies(), $request-&gt;getFiles(), $server = $request-&gt;getServer(), $request-&gt;getContent());
        if (!isset($server['HTTP_ACCEPT'])) {
            $httpRequest-&gt;headers-&gt;remove('Accept');
        }

        foreach ($this-&gt;filterFiles($httpRequest-&gt;files-&gt;all()) as $key =&gt; $value) {
            $httpRequest-&gt;files-&gt;set($key, $value);
        }

        return $httpRequest;
    }

    /**
     * Filters an array of files.
     *
     * This method created test instances of UploadedFile so that the move()
     * method can be called on those instances.
     *
     * If the size of a file is greater than the allowed size (from php.ini) then
     * an invalid UploadedFile is returned with an error set to UPLOAD_ERR_INI_SIZE.
     *
     * @see UploadedFile
     *
     * @return array
     */
    protected function filterFiles(array $files)
    {
        $filtered = [];
        foreach ($files as $key =&gt; $value) {
            if (\is_array($value)) {
                $filtered[$key] = $this-&gt;filterFiles($value);
            } elseif ($value instanceof UploadedFile) {
                if ($value-&gt;isValid() &amp;&amp; $value-&gt;getSize() &gt; UploadedFile::getMaxFilesize()) {
                    $filtered[$key] = new UploadedFile(
                        '',
                        $value-&gt;getClientOriginalName(),
                        $value-&gt;getClientMimeType(),
                        \UPLOAD_ERR_INI_SIZE,
                        true
                    );
                } else {
                    $filtered[$key] = new UploadedFile(
                        $value-&gt;getPathname(),
                        $value-&gt;getClientOriginalName(),
                        $value-&gt;getClientMimeType(),
                        $value-&gt;getError(),
                        true
                    );
                }
            }
        }

        return $filtered;
    }

    /**
     * {@inheritdoc}
     *
     * @param Response $response
     *
     * @return DomResponse
     */
    protected function filterResponse(object $response)
    {
        // this is needed to support StreamedResponse
        ob_start();
        $response-&gt;sendContent();
        $content = ob_get_clean();

        return new DomResponse($content, $response-&gt;getStatusCode(), $response-&gt;headers-&gt;all());
    }
}
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