Middleware to sign lambda requests

SignAwsRequest.php

<?php

namespace App\Http\Integrations\Middleware;

use Aws\Credentials\CredentialProvider;
use Aws\Credentials\CredentialsInterface;
use Aws\Signature\SignatureV4;
use Saloon\Contracts\RequestMiddleware;
use Saloon\Http\PendingRequest;

class SignAwsRequest implements RequestMiddleware
{
    private $credentials;

    public function __construct(CredentialsInterface $credentials = null)
    {
        $this->credentials = $credentials ?? static::loadAwsCreds();
    }

    public function __invoke(PendingRequest $pendingRequest): void
    {
        $signedHeaders = $this->generateSignedHeaders($pendingRequest);

        foreach ($signedHeaders as $headerName => $headerValue) {
            $pendingRequest->headers()->add($headerName, $headerValue);
        }
    }

    protected static function loadAwsCreds(): CredentialsInterface
    {
        $providerCallable = CredentialProvider::defaultProvider();
        return $providerCallable();
    }

    protected function generateSignedHeaders(PendingRequest $request): array
    {
        $lambdaSignature = new SignatureV4('lambda', 'eu-west-1');
        return $lambdaSignature->signRequest($request->getRequest(), $this->credentials)->getHeaders();
    }
}

TestConnector.php

<?php

namespace App\Http\Integrations;

use App\Http\Integrations\Middleware\SignAwsRequest;

class TestConnector extends Connector
{
    public function boot(PendingRequest $pendingRequest): void
    {
        if (app()->environment('production')) {
            $pendingRequest->middleware()->onRequest(new SignAwsRequest);
        }
    }
}