Enable servers to send sampling messages to clients (#101)

src/Server/ClientAwareTrait.php

@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the official PHP MCP SDK.
+ *
+ * A collaboration between Symfony and the PHP Foundation.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Mcp\Server;
+
+use Mcp\Schema\Enum\LoggingLevel;
+use Mcp\Schema\JsonRpc\Notification;
+use Mcp\Schema\Result\CreateSamplingMessageResult;
+
+/**
+ * @phpstan-import-type SampleOptions from ClientGateway
+ */
+trait ClientAwareTrait
+{
+    private ClientGateway $client;
+
+    public function setClient(ClientGateway $client): void
+    {
+        $this->client = $client;
+    }
+
+    private function notify(Notification $notification): void
+    {
+        $this->client->notify($notification);
+    }
+
+    private function log(LoggingLevel $level, mixed $data, ?string $logger = null): void
+    {
+        $this->client->log($level, $data, $logger);
+    }
+
+    private function progress(float $progress, ?float $total = null, ?string $message = null): void
+    {
+        $this->client->progress($progress, $total, $message);
+    }
+
+    /**
+     * @param SampleOptions $options
+     */
+    private function sample(string $prompt, int $maxTokens = 1000, int $timeout = 120, array $options = []): CreateSamplingMessageResult
+    {
+        return $this->client->sample($prompt, $maxTokens, $timeout, $options);
+    }
+}