feat: add support for client transports

Author: chr-hertel

README.md

@@ -26,8 +26,9 @@ configuration and usable in your chains.
 
 ### Act as Server
 
-To use your application as a MCP server, exposing tools to clients like [Claude Desktop](https://claude.ai/download),
-you need to configure in the `client` section the transports you want to use. You can use either STDIO or SSE.
+To use your application as an MCP server, exposing tools to clients like [Claude Desktop](https://claude.ai/download),
+you need to configure in the `client_transports` section the transports you want to expose to clients.
+You can use either STDIO or SSE.
 
 ## Configuration
 
@@ -46,9 +47,8 @@ mcp:
             sse:
                 url: 'http://localhost:8000/sse' # URL to SSE endpoint of MCP server
 
-    # Configure this application to act as a MCP server
-    client:
-        transports:
-            stdio: true # Enable STDIO via command
-            sse: true # Enable Server-Sent Event via controller
+    # Configure this application to act as an MCP server
+    client_transports:
+        stdio: true # Enable STDIO via command
+        sse: true # Enable Server-Sent Event via controller
 ```

composer.json

@@ -12,8 +12,12 @@
     "require": {
         "php-llm/mcp-sdk": "dev-main",
         "symfony/config": "^6.4 || ^7.0",
+        "symfony/console": "^6.4 || ^7.0",
         "symfony/dependency-injection": "^6.4 || ^7.0",
-        "symfony/framework-bundle": "^6.4 || ^7.0"
+        "symfony/framework-bundle": "^6.4 || ^7.0",
+        "symfony/http-foundation": "^6.4 || ^7.0",
+        "symfony/http-kernel": "^6.4 || ^7.0",
+        "symfony/routing": "^6.4 || ^7.0"
     },
     "require-dev": {
         "php-cs-fixer/shim": "dev-master",

src/Command/McpCommand.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpBundle\Command;
+
+use PhpLlm\McpSdk\Server;
+use PhpLlm\McpSdk\Server\Transport\Stdio\SymfonyConsoleTransport;
+use Symfony\Component\Console\Attribute\AsCommand;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+#[AsCommand('mcp:server', 'Starts an MCP server')]
+class McpCommand extends Command
+{
+    public function __construct(
+        private readonly Server $server,
+    ) {
+        parent::__construct();
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output): int
+    {
+        $this->server->connect(
+            new SymfonyConsoleTransport($input, $output)
+        );
+
+        return Command::SUCCESS;
+    }
+}

src/Controller/McpController.php

@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpBundle\Controller;
+
+use PhpLlm\McpSdk\Server;
+use PhpLlm\McpSdk\Server\Transport\Sse\Store\CachePoolStore;
+use PhpLlm\McpSdk\Server\Transport\Sse\StreamTransport;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\StreamedResponse;
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
+use Symfony\Component\Uid\Uuid;
+
+final readonly class McpController
+{
+    public function __construct(
+        private Server $server,
+        private CachePoolStore $store,
+        private UrlGeneratorInterface $urlGenerator,
+    ) {
+    }
+
+    public function sse(): StreamedResponse
+    {
+        $id = Uuid::v4();
+        $endpoint = $this->urlGenerator->generate('_mcp_messages', ['id' => $id], UrlGeneratorInterface::ABSOLUTE_URL);
+        $transport = new StreamTransport($endpoint, $this->store, $id);
+
+        return new StreamedResponse(fn () => $this->server->connect($transport), headers: [
+            'Content-Type' => 'text/event-stream',
+            'Cache-Control' => 'no-cache',
+            'X-Accel-Buffering' => 'no',
+        ]);
+    }
+
+    public function messages(Request $request, Uuid $id): Response
+    {
+        $this->store->push($id, $request->getContent());
+
+        return new Response();
+    }
+}

src/DependencyInjection/Configuration.php

@@ -14,7 +14,56 @@ public function getConfigTreeBuilder(): TreeBuilder
         $treeBuilder = new TreeBuilder('mcp');
         $rootNode = $treeBuilder->getRootNode();
 
-        //$rootNode
+        $rootNode
+            ->children()
+                ->scalarNode('app')->defaultValue('app')->end()
+                ->scalarNode('version')->defaultValue('0.0.1')->end()
+                // ->arrayNode('servers')
+                //     ->useAttributeAsKey('name')
+                //     ->arrayPrototype()
+                //         ->children()
+                //             ->enumNode('transport')
+                //                 ->values(['stdio', 'sse'])
+                //                 ->isRequired()
+                //             ->end()
+                //             ->arrayNode('stdio')
+                //                 ->children()
+                //                     ->scalarNode('command')->isRequired()->end()
+                //                     ->arrayNode('arguments')
+                //                         ->scalarPrototype()->end()
+                //                         ->defaultValue([])
+                //                     ->end()
+                //                 ->end()
+                //             ->end()
+                //             ->arrayNode('sse')
+                //                 ->children()
+                //                     ->scalarNode('url')->isRequired()->end()
+                //                 ->end()
+                //             ->end()
+                //         ->end()
+                //         ->validate()
+                //             ->ifTrue(function ($v) {
+                //                 if ('stdio' === $v['transport'] && !isset($v['stdio'])) {
+                //                     return true;
+                //                 }
+                //                 if ('sse' === $v['transport'] && !isset($v['sse'])) {
+                //                     return true;
+                //                 }
+                //
+                //                 return false;
+                //             })
+                //             ->thenInvalid('When transport is "%s", you must configure the corresponding section.')
+                //         ->end()
+                //     ->end()
+                // ->end()
+                ->arrayNode('client_transports')
+                    ->children()
+                        ->booleanNode('stdio')->defaultFalse()->end()
+                        ->booleanNode('sse')->defaultFalse()->end()
+                    ->end()
+                ->end()
+            ->end()
+        ;
 
         return $treeBuilder;
     }

src/DependencyInjection/McpExtension.php

@@ -4,6 +4,9 @@
 
 namespace PhpLlm\McpBundle\DependencyInjection;
 
+use PhpLlm\McpBundle\Command\McpCommand;
+use PhpLlm\McpBundle\Controller\McpController;
+use PhpLlm\McpBundle\Routing\RouteLoader;
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Extension\Extension;
@@ -19,5 +22,35 @@ public function load(array $configs, ContainerBuilder $container): void
         $configuration = new Configuration();
         $config = $this->processConfiguration($configuration, $configs);
 
+        $container->setParameter('mcp.app', $config['app']);
+        $container->setParameter('mcp.version', $config['version']);
+
+        if (isset($config['client_transports'])) {
+            $this->configureClient($config['client_transports'], $container);
+        }
+    }
+
+    private function configureClient($transports, ContainerBuilder $container): void
+    {
+        if (!$transports['stdio'] && !$transports['sse']) {
+            return;
+        }
+
+        if ($transports['stdio']) {
+            $container->register('mcp.server.command', McpCommand::class)
+                ->setAutowired(true)
+                ->addTag('console.command');
+        }
+
+        if ($transports['sse']) {
+            $container->register('mcp.server.controller', McpController::class)
+                ->setAutowired(true)
+                ->setPublic(true)
+                ->addTag('controller.service_arguments');
+        }
+
+        $container->register('mcp.server.route_loader', RouteLoader::class)
+            ->setArgument('$sseTransportEnabled', $transports['sse'])
+            ->addTag('routing.route_loader');
     }
 }

src/Resources/config/routes.php

@@ -0,0 +1,15 @@
+<?php
+
+use PhpLlm\McpBundle\Controller\McpController;
+use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
+
+return function (RoutingConfigurator $routes) {
+    $routes->add('_mcp_sse', '/sse')
+        ->controller([McpController::class, 'sse'])
+        ->methods(['GET'])
+    ;
+    $routes->add('_mcp_messages', '/messages/{id}')
+        ->controller([McpController::class, 'messages'])
+        ->methods(['POST'])
+    ;
+};

src/Resources/config/services.php

@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+use PhpLlm\McpSdk\Message\Factory;
+use PhpLlm\McpSdk\Server;
+use PhpLlm\McpSdk\Server\JsonRpcHandler;
+use PhpLlm\McpSdk\Server\NotificationHandler;
+use PhpLlm\McpSdk\Server\RequestHandler;
+use PhpLlm\McpSdk\Server\Transport\Sse\Store\CachePoolStore;
+
+return static function (ContainerConfigurator $container): void {
+    $container->services()
+        ->defaults()
+            ->autowire()
+            ->autoconfigure()
+        ->instanceof(NotificationHandler::class)
+            ->tag('mcp.server.notification_handler')
+        ->instanceof(RequestHandler::class)
+            ->tag('mcp.server.request_handler')
+
+        ->set(NotificationHandler\InitializedHandler::class)
+        ->set(RequestHandler\InitializeHandler::class)
+        ->args([
+            '$name' => param('mcp.app'),
+            '$version' => param('mcp.version'),
+        ])
+        ->set(RequestHandler\PingHandler::class)
+        ->set(RequestHandler\ToolCallHandler::class)
+        ->set(RequestHandler\ToolListHandler::class)
+
+        ->set('mcp.message_factory', Factory::class)
+        ->set('mcp.server.json_rpc', JsonRpcHandler::class)
+            ->args([
+                '$messageFactory' => service('mcp.message_factory'),
+                '$requestHandlers' => tagged_iterator('mcp.server.request_handler'),
+                '$notificationHandlers' => tagged_iterator('mcp.server.notification_handler'),
+            ])
+        ->set('mcp.server', Server::class)
+            ->args([
+                '$jsonRpcHandler' => service('mcp.server.json_rpc'),
+            ])
+            ->alias(Server::class, 'mcp.server')
+        ->set(CachePoolStore::class)
+    ;
+};

src/Resources/services.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PhpLlm\McpBundle\Routing;
+
+use Symfony\Component\Routing\Route;
+use Symfony\Component\Routing\RouteCollection;
+
+final readonly class RouteLoader
+{
+    public function __construct(
+        private bool $sseTransportEnabled,
+    ) {
+    }
+
+    public function __invoke(): RouteCollection
+    {
+        if (!$this->sseTransportEnabled) {
+            return new RouteCollection();
+        }
+
+        $collection = new RouteCollection();
+
+        $collection->add('_mcp_sse', new Route('/_mcp/sse', ['_controller' => ['mcp.server.controller', 'sse']], methods: ['GET']));
+        $collection->add('_mcp_messages', new Route('/_mcp/messages/{id}', ['_controller' => ['mcp.server.controller', 'messages']], methods: ['POST']));
+
+        return $collection;
+    }
+}