Idempotency

idempotency.php

<?php

namespace App\Http\Middleware;

use App\Repository\TransactionRepository;
use Closure;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Cache;
use Illuminate\Validation\ValidationException;

class Idempotency
{

    /**
     * Handle an incoming request.
     *
     * @param Request $request
     * @param Closure(\Illuminate\Http\Request): (\Illuminate\Http\Response|\Illuminate\Http\RedirectResponse)  $next
     * @return mixed
     * @throws ValidationException
     */
    public function handle(Request $request, Closure $next)
    {
        $idempotentKey = $request->header('X-Payment-Key');

        $cacheKey = Cache::get($idempotentKey);

        if(!$idempotentKey){
            $this->setError('X-Payment-Key', 'The idempotent header key is missing');
        }

        if (base64_encode(base64_decode($idempotentKey, true)) !== $idempotentKey){
            $this->setError('X-Payment-Key', 'The idempotent header key is not a valid base64 string');
        }

        if($cacheKey){
            $this->setError('X-Payment-Key', 'This subscriptions is already processing');
        }

        Cache::put($idempotentKey, $idempotentKey);

        return $next($request);
    }

    private function setError(string $field, string $error)
    {
        throw ValidationException::withMessages([
            $field => [$error],
        ]);
    }
}