ApolloUpload Middleware for Laravel

ApolloUpload.php

<?php
declare(strict_types=1);

namespace App\Http\Middleware;

use Closure;
use Illuminate\Http\Request;

/**
 * Class ApolloUpload
 */
class ApolloUpload
{
    private const GRAPHQL_OPERATIONS = 'operations';

    private const GRAPHQL_MAP = 'map';

    /**
     * @param Request $request
     * @param Closure $next
     * @return mixed
     */
    public function handle(Request $request, Closure $next)
    {
        if ($this->isApolloUpload($request)) {
            $request->request->replace($this->transform($request));
        }

        return $next($request);
    }

    /**
     * @param Request $request
     * @return bool
     */
    private function isApolloUpload(Request $request): bool
    {
        $contentType = $request->header('content-type');

        return \mb_stripos($contentType, 'multipart/form-data') !== false
            && $request->has(self::GRAPHQL_OPERATIONS)
            && $request->has(self::GRAPHQL_MAP);
    }

    /**
     * @param Request $request
     * @return array
     */
    private function transform(Request $request): array
    {
        $map = \json_decode($request->request->get(self::GRAPHQL_MAP), true);
        $operations = \json_decode($request->request->get(self::GRAPHQL_OPERATIONS), true);

        foreach ($map as $fileKey => $locations) {
            foreach ($locations as $location) {
                \array_set($operations, $location, $request->file($fileKey));
            }
        }

        return $operations;
    }
}