อัตราแลกเปลี่ยนใน PHP และ Laravel

<?php

namespace App\Services;

use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\Http;

final class ExchangeRateService
{
    public function latest(string $base, array $symbols): array
    {
        sort($symbols);
        $symbolList = implode(',', $symbols);
        $cacheKey = "fx:latest:{$base}:{$symbolList}";

        return Cache::remember($cacheKey, now()->addSeconds(60), function () use (
            $base,
            $symbolList,
        ): array {
            return Http::acceptJson()
                ->withToken(config('services.exchangerate.key'))
                ->timeout(5)
                ->get(
                    "https://api.exchangerate.dev/v1/latest/{$base}",
                    ['symbols' => $symbolList],
                )
                ->throw()
                ->json();
        });
    }
}

// config/services.php
'exchangerate' => [
    'key' => env('EXCHANGERATE_API_KEY'),
],

// .env (never commit the real value)
EXCHANGERATE_API_KEY=exr_live_...