refactor: use a custom method handler registration system

Author: CodeWithKyrian

examples/custom-method-handlers/server.php

@@ -0,0 +1,144 @@
+#!/usr/bin/env php
+<?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.
+ */
+
+require_once dirname(__DIR__).'/bootstrap.php';
+chdir(__DIR__);
+
+use Mcp\Schema\Content\TextContent;
+use Mcp\Schema\JsonRpc\Error;
+use Mcp\Schema\JsonRpc\HasMethodInterface;
+use Mcp\Schema\JsonRpc\Response;
+use Mcp\Schema\Request\CallToolRequest;
+use Mcp\Schema\Request\ListToolsRequest;
+use Mcp\Schema\Result\CallToolResult;
+use Mcp\Schema\Result\ListToolsResult;
+use Mcp\Schema\ServerCapabilities;
+use Mcp\Schema\Tool;
+use Mcp\Server;
+use Mcp\Server\Handler\MethodHandlerInterface;
+use Mcp\Server\Session\SessionInterface;
+use Mcp\Server\Transport\StdioTransport;
+
+logger()->info('Starting MCP Custom Method Handlers (Stdio) Server...');
+
+$toolDefinitions = [
+    'say_hello' => new Tool(
+        name: 'say_hello',
+        inputSchema: [
+            'type' => 'object',
+            'properties' => [
+                'name' => ['type' => 'string', 'description' => 'Name to greet'],
+            ],
+            'required' => ['name'],
+        ],
+        description: 'Greets a user by name.',
+        annotations: null,
+    ),
+    'sum' => new Tool(
+        name: 'sum',
+        inputSchema: [
+            'type' => 'object',
+            'properties' => [
+                'a' => ['type' => 'number'],
+                'b' => ['type' => 'number'],
+            ],
+            'required' => ['a', 'b'],
+        ],
+        description: 'Returns a+b.',
+        annotations: null,
+    ),
+];
+
+$listToolsHandler = new class($toolDefinitions) implements MethodHandlerInterface {
+    /**
+     * @param array<string, Tool> $toolDefinitions
+     */
+    public function __construct(private array $toolDefinitions)
+    {
+    }
+
+    public function supports(HasMethodInterface $message): bool
+    {
+        return $message instanceof ListToolsRequest;
+    }
+
+    public function handle(ListToolsRequest|HasMethodInterface $message, SessionInterface $session): Response
+    {
+        assert($message instanceof ListToolsRequest);
+
+        return new Response($message->getId(), new ListToolsResult(array_values($this->toolDefinitions), null));
+    }
+};
+
+$callToolHandler = new class($toolDefinitions) implements MethodHandlerInterface {
+    /**
+     * @param array<string, Tool> $toolDefinitions
+     */
+    public function __construct(private array $toolDefinitions)
+    {
+    }
+
+    public function supports(HasMethodInterface $message): bool
+    {
+        return $message instanceof CallToolRequest;
+    }
+
+    public function handle(CallToolRequest|HasMethodInterface $message, SessionInterface $session): Response|Error
+    {
+        assert($message instanceof CallToolRequest);
+
+        $name = $message->name;
+        $args = $message->arguments ?? [];
+
+        if (!isset($this->toolDefinitions[$name])) {
+            return new Error($message->getId(), Error::METHOD_NOT_FOUND, sprintf('Tool not found: %s', $name));
+        }
+
+        try {
+            switch ($name) {
+                case 'say_hello':
+                    $greetName = (string) ($args['name'] ?? 'world');
+                    $result = [new TextContent(sprintf('Hello, %s!', $greetName))];
+                    break;
+                case 'sum':
+                    $a = (float) ($args['a'] ?? 0);
+                    $b = (float) ($args['b'] ?? 0);
+                    $result = [new TextContent((string) ($a + $b))];
+                    break;
+                default:
+                    $result = [new TextContent('Unknown tool')];
+            }
+
+            return new Response($message->getId(), new CallToolResult($result));
+        } catch (Throwable $e) {
+            return new Response($message->getId(), new CallToolResult([new TextContent('Tool execution failed')], true));
+        }
+    }
+};
+
+$capabilities = new ServerCapabilities(tools: true, resources: false, prompts: false);
+
+$server = Server::builder()
+    ->setServerInfo('Custom Handlers Server', '1.0.0')
+    ->setLogger(logger())
+    ->setContainer(container())
+    ->setCapabilities($capabilities)
+    ->addMethodHandlers([$listToolsHandler, $callToolHandler])
+    ->build();
+
+$transport = new StdioTransport(logger: logger());
+
+$server->connect($transport);
+
+$transport->listen();
+
+logger()->info('Server listener stopped gracefully.');