a1e0f61b6b* Implemented MCP logging specification with auto-injection * Add RequestContext * fix tests and style * Better deprecation * fix: minor * Remove ClientAwareInterface * fix cs * fix docs --------- Co-authored-by: Adam Jamiu <jamiuadam120@gmail.com>
597 lines
21 KiB
PHP
597 lines
21 KiB
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.
|
|
*/
|
|
|
|
namespace Mcp\Server;
|
|
|
|
use Mcp\Exception\InvalidInputMessageException;
|
|
use Mcp\JsonRpc\MessageFactory;
|
|
use Mcp\Schema\JsonRpc\Error;
|
|
use Mcp\Schema\JsonRpc\Notification;
|
|
use Mcp\Schema\JsonRpc\Request;
|
|
use Mcp\Schema\JsonRpc\Response;
|
|
use Mcp\Schema\JsonRpc\ResultInterface;
|
|
use Mcp\Schema\Request\InitializeRequest;
|
|
use Mcp\Server\Handler\Notification\NotificationHandlerInterface;
|
|
use Mcp\Server\Handler\Request\RequestHandlerInterface;
|
|
use Mcp\Server\Session\SessionFactoryInterface;
|
|
use Mcp\Server\Session\SessionInterface;
|
|
use Mcp\Server\Session\SessionStoreInterface;
|
|
use Mcp\Server\Transport\TransportInterface;
|
|
use Psr\Log\LoggerInterface;
|
|
use Psr\Log\NullLogger;
|
|
use Symfony\Component\Uid\Uuid;
|
|
|
|
/**
|
|
* @final
|
|
*
|
|
* @phpstan-import-type McpFiber from TransportInterface
|
|
* @phpstan-import-type FiberSuspend from TransportInterface
|
|
*
|
|
* @author Christopher Hertel <mail@christopher-hertel.de>
|
|
* @author Kyrian Obikwelu <koshnawaza@gmail.com>
|
|
*/
|
|
class Protocol
|
|
{
|
|
/** Session key for request ID counter */
|
|
private const SESSION_REQUEST_ID_COUNTER = '_mcp.request_id_counter';
|
|
|
|
/** Session key for pending outgoing requests */
|
|
private const SESSION_PENDING_REQUESTS = '_mcp.pending_requests';
|
|
|
|
/** Session key for incoming client responses */
|
|
private const SESSION_RESPONSES = '_mcp.responses';
|
|
|
|
/** Session key for outgoing message queue */
|
|
private const SESSION_OUTGOING_QUEUE = '_mcp.outgoing_queue';
|
|
|
|
/** Session key for active request meta */
|
|
public const SESSION_ACTIVE_REQUEST_META = '_mcp.active_request_meta';
|
|
|
|
public const SESSION_LOGGING_LEVEL = '_mcp.logging_level';
|
|
|
|
/**
|
|
* @param array<int, RequestHandlerInterface<ResultInterface|array<string, mixed>>> $requestHandlers
|
|
* @param array<int, NotificationHandlerInterface> $notificationHandlers
|
|
*/
|
|
public function __construct(
|
|
private readonly array $requestHandlers,
|
|
private readonly array $notificationHandlers,
|
|
private readonly MessageFactory $messageFactory,
|
|
private readonly SessionFactoryInterface $sessionFactory,
|
|
private readonly SessionStoreInterface $sessionStore,
|
|
private readonly LoggerInterface $logger = new NullLogger(),
|
|
) {
|
|
}
|
|
|
|
/**
|
|
* Connect this protocol to transport.
|
|
*
|
|
* The protocol takes ownership of the transport and sets up all callbacks.
|
|
*
|
|
* @param TransportInterface<mixed> $transport
|
|
*/
|
|
public function connect(TransportInterface $transport): void
|
|
{
|
|
$transport->onMessage($this->processInput(...));
|
|
|
|
$transport->onSessionEnd($this->destroySession(...));
|
|
|
|
$transport->setOutgoingMessagesProvider($this->consumeOutgoingMessages(...));
|
|
|
|
$transport->setPendingRequestsProvider($this->getPendingRequests(...));
|
|
|
|
$transport->setResponseFinder($this->checkResponse(...));
|
|
|
|
$transport->setFiberYieldHandler($this->handleFiberYield(...));
|
|
|
|
$this->logger->info('Protocol connected to transport', ['transport' => $transport::class]);
|
|
}
|
|
|
|
/**
|
|
* Handle an incoming message from the transport.
|
|
*
|
|
* This is called by the transport whenever ANY message arrives.
|
|
*
|
|
* @param TransportInterface<mixed> $transport
|
|
*/
|
|
public function processInput(TransportInterface $transport, string $input, ?Uuid $sessionId): void
|
|
{
|
|
$this->logger->info('Received message to process.', ['message' => $input]);
|
|
|
|
$this->gcSessions();
|
|
|
|
try {
|
|
$messages = $this->messageFactory->create($input);
|
|
} catch (\JsonException $e) {
|
|
$this->logger->warning('Failed to decode json message.', ['exception' => $e]);
|
|
$error = Error::forParseError($e->getMessage());
|
|
$this->sendResponse($transport, $error, null);
|
|
|
|
return;
|
|
}
|
|
|
|
$session = $this->resolveSession($transport, $sessionId, $messages);
|
|
if (null === $session) {
|
|
return;
|
|
}
|
|
|
|
foreach ($messages as $message) {
|
|
if ($message instanceof InvalidInputMessageException) {
|
|
$this->handleInvalidMessage($transport, $message, $session);
|
|
} elseif ($message instanceof Request) {
|
|
$this->handleRequest($transport, $message, $session);
|
|
} elseif ($message instanceof Response || $message instanceof Error) {
|
|
$this->handleResponse($message, $session);
|
|
} elseif ($message instanceof Notification) {
|
|
$this->handleNotification($message, $session);
|
|
}
|
|
}
|
|
|
|
$session->save();
|
|
}
|
|
|
|
/**
|
|
* Handle an invalid message from the transport.
|
|
*
|
|
* @param TransportInterface<mixed> $transport
|
|
*/
|
|
private function handleInvalidMessage(TransportInterface $transport, InvalidInputMessageException $exception, SessionInterface $session): void
|
|
{
|
|
$this->logger->warning('Failed to create message.', ['exception' => $exception]);
|
|
|
|
$error = Error::forInvalidRequest($exception->getMessage());
|
|
$this->sendResponse($transport, $error, $session);
|
|
}
|
|
|
|
/**
|
|
* Handle a request from the transport.
|
|
*
|
|
* @param TransportInterface<mixed> $transport
|
|
*/
|
|
private function handleRequest(TransportInterface $transport, Request $request, SessionInterface $session): void
|
|
{
|
|
$this->logger->info('Handling request.', ['request' => $request]);
|
|
|
|
$session->set(self::SESSION_ACTIVE_REQUEST_META, $request->getMeta());
|
|
|
|
$handlerFound = false;
|
|
|
|
foreach ($this->requestHandlers as $handler) {
|
|
if (!$handler->supports($request)) {
|
|
continue;
|
|
}
|
|
|
|
$handlerFound = true;
|
|
|
|
try {
|
|
/** @var McpFiber $fiber */
|
|
$fiber = new \Fiber(fn () => $handler->handle($request, $session));
|
|
|
|
$result = $fiber->start();
|
|
|
|
if ($fiber->isSuspended()) {
|
|
if (\is_array($result) && isset($result['type'])) {
|
|
if ('notification' === $result['type']) {
|
|
$notification = $result['notification'];
|
|
$this->sendNotification($notification, $session);
|
|
} elseif ('request' === $result['type']) {
|
|
$request = $result['request'];
|
|
$timeout = $result['timeout'] ?? 120;
|
|
$this->sendRequest($request, $timeout, $session);
|
|
}
|
|
}
|
|
|
|
$transport->attachFiberToSession($fiber, $session->getId());
|
|
|
|
return;
|
|
} else {
|
|
$finalResult = $fiber->getReturn();
|
|
|
|
$this->sendResponse($transport, $finalResult, $session);
|
|
}
|
|
} catch (\InvalidArgumentException $e) {
|
|
$this->logger->warning(\sprintf('Invalid argument: %s', $e->getMessage()), ['exception' => $e]);
|
|
|
|
$error = Error::forInvalidParams($e->getMessage(), $request->getId());
|
|
$this->sendResponse($transport, $error, $session);
|
|
} catch (\Throwable $e) {
|
|
$this->logger->error(\sprintf('Uncaught exception: %s', $e->getMessage()), ['exception' => $e]);
|
|
|
|
$error = Error::forInternalError($e->getMessage(), $request->getId());
|
|
$this->sendResponse($transport, $error, $session);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
if (!$handlerFound) {
|
|
$error = Error::forMethodNotFound(\sprintf('No handler found for method "%s".', $request::getMethod()), $request->getId());
|
|
$this->sendResponse($transport, $error, $session);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @param Response<array<string, mixed>>|Error $response
|
|
*/
|
|
private function handleResponse(Response|Error $response, SessionInterface $session): void
|
|
{
|
|
$this->logger->info('Handling response from client.', ['response' => $response]);
|
|
|
|
$messageId = $response->getId();
|
|
|
|
$session->set(self::SESSION_RESPONSES.".{$messageId}", $response->jsonSerialize());
|
|
$session->forget(self::SESSION_ACTIVE_REQUEST_META);
|
|
|
|
$this->logger->info('Client response stored in session', [
|
|
'message_id' => $messageId,
|
|
]);
|
|
}
|
|
|
|
private function handleNotification(Notification $notification, SessionInterface $session): void
|
|
{
|
|
$this->logger->info('Handling notification.', ['notification' => $notification]);
|
|
|
|
foreach ($this->notificationHandlers as $handler) {
|
|
if (!$handler->supports($notification)) {
|
|
continue;
|
|
}
|
|
|
|
try {
|
|
$handler->handle($notification, $session);
|
|
} catch (\Throwable $e) {
|
|
$this->logger->error(\sprintf('Error while handling notification: %s', $e->getMessage()), ['exception' => $e]);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Sends a request to the client and returns the request ID.
|
|
*/
|
|
public function sendRequest(Request $request, int $timeout, SessionInterface $session): int
|
|
{
|
|
$counter = $session->get(self::SESSION_REQUEST_ID_COUNTER, 1000);
|
|
$requestId = $counter++;
|
|
$session->set(self::SESSION_REQUEST_ID_COUNTER, $counter);
|
|
|
|
$requestWithId = $request->withId($requestId);
|
|
|
|
$this->logger->info('Queueing server request to client', [
|
|
'request_id' => $requestId,
|
|
'method' => $request::getMethod(),
|
|
]);
|
|
|
|
$pending = $session->get(self::SESSION_PENDING_REQUESTS, []);
|
|
$pending[$requestId] = [
|
|
'request_id' => $requestId,
|
|
'timeout' => $timeout,
|
|
'timestamp' => time(),
|
|
];
|
|
$session->set(self::SESSION_PENDING_REQUESTS, $pending);
|
|
|
|
$this->queueOutgoing($requestWithId, ['type' => 'request'], $session);
|
|
|
|
return $requestId;
|
|
}
|
|
|
|
/**
|
|
* Queues a notification for later delivery.
|
|
*/
|
|
public function sendNotification(Notification $notification, SessionInterface $session): void
|
|
{
|
|
$this->logger->info('Queueing server notification to client', [
|
|
'method' => $notification::getMethod(),
|
|
]);
|
|
|
|
$this->queueOutgoing($notification, ['type' => 'notification'], $session);
|
|
}
|
|
|
|
/**
|
|
* Sends a response either immediately or queued for later delivery.
|
|
*
|
|
* @param TransportInterface<mixed> $transport
|
|
* @param Response<ResultInterface|array<string, mixed>>|Error $response
|
|
* @param array<string, mixed> $context
|
|
*/
|
|
private function sendResponse(TransportInterface $transport, Response|Error $response, ?SessionInterface $session, array $context = []): void
|
|
{
|
|
if (null === $session) {
|
|
$this->logger->info('Sending immediate response', [
|
|
'response_id' => $response->getId(),
|
|
]);
|
|
|
|
try {
|
|
$encoded = json_encode($response, \JSON_THROW_ON_ERROR);
|
|
} catch (\JsonException $e) {
|
|
$this->logger->error('Failed to encode response to JSON.', [
|
|
'message_id' => $response->getId(),
|
|
'exception' => $e,
|
|
]);
|
|
|
|
$fallbackError = new Error(
|
|
id: $response->getId(),
|
|
code: Error::INTERNAL_ERROR,
|
|
message: 'Response could not be encoded to JSON'
|
|
);
|
|
|
|
$encoded = json_encode($fallbackError, \JSON_THROW_ON_ERROR);
|
|
}
|
|
|
|
$context['type'] = 'response';
|
|
$transport->send($encoded, $context);
|
|
} else {
|
|
$this->logger->info('Queueing server response', [
|
|
'response_id' => $response->getId(),
|
|
]);
|
|
|
|
$this->queueOutgoing($response, ['type' => 'response'], $session);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Helper to queue outgoing messages in session.
|
|
*
|
|
* @param Request|Notification|Response<ResultInterface|array<string, mixed>>|Error $message
|
|
* @param array<string, mixed> $context
|
|
*/
|
|
private function queueOutgoing(Request|Notification|Response|Error $message, array $context, SessionInterface $session): void
|
|
{
|
|
try {
|
|
$encoded = json_encode($message, \JSON_THROW_ON_ERROR);
|
|
} catch (\JsonException $e) {
|
|
$this->logger->error('Failed to encode message to JSON.', [
|
|
'exception' => $e,
|
|
]);
|
|
|
|
return;
|
|
}
|
|
|
|
$queue = $session->get(self::SESSION_OUTGOING_QUEUE, []);
|
|
$queue[] = [
|
|
'message' => $encoded,
|
|
'context' => $context,
|
|
];
|
|
$session->set(self::SESSION_OUTGOING_QUEUE, $queue);
|
|
}
|
|
|
|
/**
|
|
* Consume (get and clear) all outgoing messages for a session.
|
|
*
|
|
* @return array<int, array{message: string, context: array<string, mixed>}>
|
|
*/
|
|
public function consumeOutgoingMessages(Uuid $sessionId): array
|
|
{
|
|
$session = $this->sessionFactory->createWithId($sessionId, $this->sessionStore);
|
|
$queue = $session->get(self::SESSION_OUTGOING_QUEUE, []);
|
|
$session->set(self::SESSION_OUTGOING_QUEUE, []);
|
|
$session->save();
|
|
|
|
return $queue;
|
|
}
|
|
|
|
/**
|
|
* Check for a response to a specific request ID.
|
|
*
|
|
* When a response is found, it is removed from the session, and the
|
|
* corresponding pending request is also cleared.
|
|
*/
|
|
/**
|
|
* @return Response<array<string, mixed>>|Error|null
|
|
*/
|
|
public function checkResponse(int $requestId, Uuid $sessionId): Response|Error|null
|
|
{
|
|
$session = $this->sessionFactory->createWithId($sessionId, $this->sessionStore);
|
|
$responseData = $session->get(self::SESSION_RESPONSES.".{$requestId}");
|
|
|
|
if (null === $responseData) {
|
|
return null;
|
|
}
|
|
|
|
$this->logger->debug('Found and consuming client response.', [
|
|
'request_id' => $requestId,
|
|
'session_id' => $sessionId->toRfc4122(),
|
|
]);
|
|
|
|
$session->set(self::SESSION_RESPONSES.".{$requestId}", null);
|
|
$pending = $session->get(self::SESSION_PENDING_REQUESTS, []);
|
|
unset($pending[$requestId]);
|
|
$session->set(self::SESSION_PENDING_REQUESTS, $pending);
|
|
$session->save();
|
|
|
|
try {
|
|
if (isset($responseData['error'])) {
|
|
return Error::fromArray($responseData);
|
|
}
|
|
|
|
return Response::fromArray($responseData);
|
|
} catch (\Throwable $e) {
|
|
$this->logger->error('Failed to reconstruct client response from session.', [
|
|
'request_id' => $requestId,
|
|
'exception' => $e,
|
|
'response_data' => $responseData,
|
|
]);
|
|
|
|
return null;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Get pending requests for a session.
|
|
*
|
|
* @return array<int, mixed> The pending requests
|
|
*/
|
|
public function getPendingRequests(Uuid $sessionId): array
|
|
{
|
|
$session = $this->sessionFactory->createWithId($sessionId, $this->sessionStore);
|
|
|
|
return $session->get(self::SESSION_PENDING_REQUESTS, []);
|
|
}
|
|
|
|
/**
|
|
* Handle values yielded by Fibers during transport-managed resumes.
|
|
*
|
|
* @param FiberSuspend|null $yieldedValue
|
|
*/
|
|
public function handleFiberYield(mixed $yieldedValue, ?Uuid $sessionId): void
|
|
{
|
|
if (!$sessionId) {
|
|
$this->logger->warning('Fiber yielded value without associated session context.');
|
|
|
|
return;
|
|
}
|
|
|
|
if (!\is_array($yieldedValue) || !isset($yieldedValue['type'])) {
|
|
$this->logger->warning('Fiber yielded unexpected payload.', [
|
|
'payload' => $yieldedValue,
|
|
'session_id' => $sessionId->toRfc4122(),
|
|
]);
|
|
|
|
return;
|
|
}
|
|
|
|
$session = $this->sessionFactory->createWithId($sessionId, $this->sessionStore);
|
|
|
|
$payloadSessionId = $yieldedValue['session_id'] ?? null;
|
|
if (\is_string($payloadSessionId) && $payloadSessionId !== $sessionId->toRfc4122()) {
|
|
$this->logger->warning('Fiber yielded payload with mismatched session ID.', [
|
|
'payload_session_id' => $payloadSessionId,
|
|
'expected_session_id' => $sessionId->toRfc4122(),
|
|
]);
|
|
}
|
|
|
|
try {
|
|
if ('notification' === $yieldedValue['type']) {
|
|
$notification = $yieldedValue['notification'] ?? null;
|
|
if (!$notification instanceof Notification) {
|
|
$this->logger->warning('Fiber yielded notification without Notification instance.', [
|
|
'payload' => $yieldedValue,
|
|
]);
|
|
|
|
return;
|
|
}
|
|
|
|
$this->sendNotification($notification, $session);
|
|
} elseif ('request' === $yieldedValue['type']) {
|
|
$request = $yieldedValue['request'] ?? null;
|
|
if (!$request instanceof Request) {
|
|
$this->logger->warning('Fiber yielded request without Request instance.', [
|
|
'payload' => $yieldedValue,
|
|
]);
|
|
|
|
return;
|
|
}
|
|
|
|
$timeout = isset($yieldedValue['timeout']) ? (int) $yieldedValue['timeout'] : 120;
|
|
$this->sendRequest($request, $timeout, $session);
|
|
} else {
|
|
$this->logger->warning('Fiber yielded unknown operation type.', [
|
|
'type' => $yieldedValue['type'],
|
|
]);
|
|
}
|
|
} finally {
|
|
$session->save();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @param array<int, mixed> $messages
|
|
*/
|
|
private function hasInitializeRequest(array $messages): bool
|
|
{
|
|
foreach ($messages as $message) {
|
|
if ($message instanceof InitializeRequest) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Resolves and validates the session based on the request context.
|
|
*
|
|
* @param TransportInterface<mixed> $transport
|
|
* @param Uuid|null $sessionId The session ID from the transport
|
|
* @param array<int,mixed> $messages The parsed messages
|
|
*/
|
|
private function resolveSession(TransportInterface $transport, ?Uuid $sessionId, array $messages): ?SessionInterface
|
|
{
|
|
if ($this->hasInitializeRequest($messages)) {
|
|
// Spec: An initialize request must not be part of a batch.
|
|
if (\count($messages) > 1) {
|
|
$error = Error::forInvalidRequest('The "initialize" request MUST NOT be part of a batch.');
|
|
$this->sendResponse($transport, $error, null);
|
|
|
|
return null;
|
|
}
|
|
|
|
// Spec: An initialize request must not have a session ID.
|
|
if ($sessionId) {
|
|
$error = Error::forInvalidRequest('A session ID MUST NOT be sent with an "initialize" request.');
|
|
$this->sendResponse($transport, $error, null);
|
|
|
|
return null;
|
|
}
|
|
|
|
$session = $this->sessionFactory->create($this->sessionStore);
|
|
$this->logger->debug('Created new session for initialize', [
|
|
'session_id' => $session->getId()->toRfc4122(),
|
|
]);
|
|
|
|
$transport->setSessionId($session->getId());
|
|
|
|
return $session;
|
|
}
|
|
|
|
if (!$sessionId) {
|
|
$error = Error::forInvalidRequest('A valid session id is REQUIRED for non-initialize requests.');
|
|
$this->sendResponse($transport, $error, null, ['status_code' => 400]);
|
|
|
|
return null;
|
|
}
|
|
|
|
if (!$this->sessionStore->exists($sessionId)) {
|
|
$error = Error::forInvalidRequest('Session not found or has expired.');
|
|
$this->sendResponse($transport, $error, null, ['status_code' => 404]);
|
|
|
|
return null;
|
|
}
|
|
|
|
return $this->sessionFactory->createWithId($sessionId, $this->sessionStore);
|
|
}
|
|
|
|
/**
|
|
* Run garbage collection on expired sessions.
|
|
* Uses the session store's internal TTL configuration.
|
|
*/
|
|
private function gcSessions(): void
|
|
{
|
|
if (random_int(0, 100) > 1) {
|
|
return;
|
|
}
|
|
|
|
$deletedSessions = $this->sessionStore->gc();
|
|
if (!empty($deletedSessions)) {
|
|
$this->logger->debug('Garbage collected expired sessions.', [
|
|
'count' => \count($deletedSessions),
|
|
'session_ids' => array_map(fn (Uuid $id) => $id->toRfc4122(), $deletedSessions),
|
|
]);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Destroy a specific session.
|
|
*/
|
|
public function destroySession(Uuid $sessionId): void
|
|
{
|
|
$this->sessionStore->destroy($sessionId);
|
|
$this->logger->info('Session destroyed.', ['session_id' => $sessionId->toRfc4122()]);
|
|
}
|
|
}
|