Laravel middleware to fix form-data/multipart in PATCH, PUT requests

MultipartFix.php

<?php

declare(strict_types=1);

namespace App\Http\Middleware;

use Closure;
use Exception;
use Illuminate\Http\Request;
use Illuminate\Http\UploadedFile;
use Log;
use Symfony\Component\HttpFoundation\ParameterBag;

/**
 * @author https://github.com/opiy-org
 * @author https://github.com/Stunext
 *
 * PHP, and Laravel does not support multipart/form-data requests when using any request method other than POST.
 * This limits the ability to implement RESTful architectures. This is a middleware for Laravel 8 that manually decoding
 * the php://input stream when the request type is PUT or PATCH and the Content-Type header is mutlipart/form-data.
 *
 * this implementation is based on https://gist.github.com/Stunext/9171b7a8f3633b0b601a0feb8088dca1
 * by https://github.com/Stunext
 */
class MultipartFix
{
    private const SKIP_METHODS = [
        Request::METHOD_POST,
        Request::METHOD_GET,
    ];
    private const LINE_BREAK = "\r\n";
    private const CONTENT_TYPE = 'content-type';
    private const CONTENT_DISPOSITION = 'content-disposition';
    private const FILENAME_PREFIX = 'mtp';

    /**
     * Handle an incoming request.
     *
     * @param Request $request
     * @param Closure $next
     * @return mixed
     */
    public function handle(Request $request, Closure $next): mixed
    {
        if (in_array($request->method(), self::SKIP_METHODS)) {
            return $next($request);
        }

        if (preg_match('/multipart\/form-data/i', $request->headers->get(self::CONTENT_TYPE))) {
            try {
                $parameters = $this->getRequestFromStdIn();

                $request->merge($parameters['inputs']);
                $request->files->add($parameters['files']);
            } catch (Exception $exception) {
                Log::error('MultipartFix error', [
                    'error_message' => $exception->getMessage(),
                ]);
            }
        }

        return $next($request);
    }

    /**
     * @return array
     * @throws Exception
     */
    public function getRequestFromStdIn(): array
    {
        $files = [];
        $fieldsData = [];

        $rawData = file_get_contents('php://input');
        if (!$rawData) {
            throw new Exception('Can not read from stdin');
        }

        // Fetch content and determine boundary
        $boundary = substr($rawData, 0, strpos($rawData, self::LINE_BREAK));
        if (strlen($boundary) === 0) {
            throw new Exception('Wrong data format');
        }

        // Fetch and process each part
        $dataArr = explode($boundary, $rawData);
        $dataParts = array_slice($dataArr, 1);
        foreach ($dataParts as $part) {
            // If this is the last part, break
            if ($part === '--' . self::LINE_BREAK) {
                break;
            }
            // Separate content from headers
            $part = ltrim($part, self::LINE_BREAK);
            [$rawHeaders, $content] = explode(self::LINE_BREAK . self::LINE_BREAK, $part, 2);
            $content = substr($content, 0, strlen($content) - 2);
            // Parse the headers list
            $rawHeaders = explode(self::LINE_BREAK, $rawHeaders);
            $headers = [];
            foreach ($rawHeaders as $header) {
                [$name, $value] = explode(':', $header);
                $headers[strtolower($name)] = ltrim($value, ' ');
            }
            // Parse the Content-Disposition to get the field name, etc.
            if (isset($headers[self::CONTENT_DISPOSITION])) {
                preg_match(
                    '/^form-data; *name="([^"]+)"(; *filename="([^"]+)")?/',
                    $headers[self::CONTENT_DISPOSITION],
                    $matches
                );
                $fieldName = $matches[1];
                $fileName = $matches[3] ?? null;
                // If we have a file, save it. Otherwise, save the data.
                if ($fileName) {
                    $localFileName = tempnam(sys_get_temp_dir(), self::FILENAME_PREFIX);
                    file_put_contents($localFileName, $content);
                    $files[$fieldName] = new UploadedFile($localFileName, $fileName, $headers[self::CONTENT_TYPE]);

                    // register a shutdown function to cleanup the temporary file
                    register_shutdown_function(static function () use ($localFileName) {
                        unlink($localFileName);
                    });
                } else {
                    $fieldsData[$fieldName] = $content;
                }
            }
        }

        $fields = new ParameterBag($fieldsData);

        return ['inputs' => $fields->all(), 'files' => $files];
    }
}