Refactor point value object and add observability

server/src/Service/ClientKeyProvider.php

@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\Exception\MissingClientKeyException;
+use Psr\Log\LoggerInterface;
+use Symfony\Component\HttpFoundation\Request;
+
+final class ClientKeyProvider
+{
+    public function __construct(
+        private readonly LoggerInterface $logger,
+    ) {
+    }
+
+    public function fromRequest(Request $request): string
+    {
+        $ip = $this->extractClientIp($request);
+
+        $clientKey = $this->hashIp($ip);
+        $this->logger->debug('Generated client key for request.', [
+            'client_key' => $clientKey,
+        ]);
+
+        return $clientKey;
+    }
+
+    private function extractClientIp(Request $request): string
+    {
+        $forwarded = $request->headers->get('X-Forwarded-For');
+        if ($forwarded !== null && $forwarded !== '') {
+            $parts = array_filter(array_map('trim', explode(',', $forwarded)));
+            if ($parts !== []) {
+                $this->logger->info('Resolved client address from forwarded header.', [
+                    'resolution' => 'forwarded',
+                ]);
+                return $parts[0];
+            }
+        }
+
+        $ip = $request->getClientIp();
+        if (is_string($ip) && $ip !== '') {
+            $this->logger->info('Resolved client address from remote address.', [
+                'resolution' => 'remote',
+            ]);
+            return $ip;
+        }
+
+        $this->logger->critical('Failed to resolve client address for key generation.');
+        throw new MissingClientKeyException();
+    }
+
+    private function hashIp(string $ip): string
+    {
+        return substr(hash('sha256', $ip), 0, 12);
+    }
+}