pkg/dds/lib/src/dds_impl.dart - sdk.git - Git at Google

 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 part of dds;

 class _DartDevelopmentService implements DartDevelopmentService {
   _DartDevelopmentService(
     this._remoteVmServiceUri,
     this._uri,
     this._authCodesEnabled,
   ) {
     _clientManager = _ClientManager(this);
     _expressionEvaluator = _ExpressionEvaluator(this);
     _isolateManager = _IsolateManager(this);
     _loggingRepository = _LoggingRepository();
     _streamManager = _StreamManager(this);
     _authCode = _authCodesEnabled ? _makeAuthToken() : '';
   }

   Future<void> startService() async {
     // TODO(bkonyi): throw if we've already shutdown.
     // Establish the connection to the VM service.
     _vmServiceSocket = WebSocketChannel.connect(remoteVmServiceWsUri);
     _vmServiceClient = _BinaryCompatiblePeer(_vmServiceSocket, _streamManager);
     // Setup the JSON RPC client with the VM service.
     unawaited(_vmServiceClient.listen().then((_) => shutdown()));

     // Setup stream event handling.
     await streamManager.listen();

     // Populate initial isolate state.
     await _isolateManager.initialize();

     // Once we have a connection to the VM service, we're ready to spawn the intermediary.
     await _startDDSServer();
   }

   Future<void> _startDDSServer() async {
     // No provided address, bind to an available port on localhost.
     // TODO(bkonyi): handle case where there's no IPv4 loopback.
     final host = uri?.host ?? InternetAddress.loopbackIPv4.host;
     final port = uri?.port ?? 0;

     // Start the DDS server.
     _server = await io.serve(
         const Pipeline()
             .addMiddleware(_authCodeMiddleware)
             .addHandler(_handlers().handler),
         host,
         port);

     final tmpUri = Uri(
       scheme: 'http',
       host: host,
       port: _server.port,
       path: '$_authCode/',
     );

     // Notify the VM service that this client is DDS and that it should close
     // and refuse connections from other clients. DDS is now acting in place of
     // the VM service.
     try {
       await _vmServiceClient.sendRequest('_yieldControlToDDS', {
         'uri': tmpUri.toString(),
       });
     } on json_rpc.RpcException catch (e) {
       await _server.close(force: true);
       // _yieldControlToDDS fails if DDS is not the only VM service client.
       throw DartDevelopmentServiceException._(e.data['details']);
     }

     _uri = tmpUri;
   }

   /// Stop accepting requests after gracefully handling existing requests.
   Future<void> shutdown() async {
     if (_done.isCompleted || _shuttingDown) {
       // Already shutdown.
       return;
     }
     _shuttingDown = true;
     // Don't accept anymore HTTP requests.
     await _server?.close();

     // Close connections to clients.
     await clientManager.shutdown();

     // Close connection to VM service.
     await _vmServiceSocket.sink.close();

     _done.complete();
   }

   /// Generates a base64 authentication code that must be passed as the first
   /// part of the request path. Used to prevent random connections from clients
   /// watching the common service ports.
   static String _makeAuthToken() {
     final kTokenByteSize = 8;
     final bytes = Uint8List(kTokenByteSize);
     final random = Random.secure();
     for (int i = 0; i < kTokenByteSize; i++) {
       bytes[i] = random.nextInt(256);
     }
     return base64Url.encode(bytes);
   }

   /// Shelf middleware to verify authentication tokens before processing a
   /// request.
   ///
   /// If authentication codes are enabled, a 403 response is returned if the
   /// authentication code is not the first element of the request's path.
   /// Otherwise, the request is forwarded to the first handler.
   Handler _authCodeMiddleware(Handler innerHandler) => (Request request) {
         if (_authCodesEnabled) {
           final forbidden =
               Response.forbidden('missing or invalid authentication code');
           final pathSegments = request.url.pathSegments;
           if (pathSegments.isEmpty) {
             return forbidden;
           }
           final authToken = pathSegments[0];
           if (authToken != _authCode) {
             return forbidden;
           }
           // Creates a new request with the authentication code stripped from
           // the request URI. This method doesn't behave as you might expect.
           // Calling request.change(path: authToken) has the effect of changing
           // the request's handler path from '/' to '/$authToken/' while also
           // changing the request's url from '$authToken/restofpath/' to
           // 'restofpath/'. The handler path is only used by shelf, so this
           // operation has the effect of stripping the authentication code from
           // the request.
           request = request.change(path: authToken);
         }
         return innerHandler(request);
       };

   // Attempt to upgrade HTTP requests to a websocket before processing them as
   // standard HTTP requests. The websocket handler will fail quickly if the
   // request doesn't appear to be a websocket upgrade request.
   Cascade _handlers() {
     return Cascade()
         .add(_webSocketHandler())
         .add(_sseHandler())
         .add(_httpHandler());
   }

   Handler _webSocketHandler() => webSocketHandler((WebSocketChannel ws) {
         final client = _DartDevelopmentServiceClient.fromWebSocket(
           this,
           ws,
           _vmServiceClient,
         );
         clientManager.addClient(client);
       });

   Handler _sseHandler() {
     final handler = authCodesEnabled
         ? SseHandler(Uri.parse('/$_authCode/$_kSseHandlerPath'))
         : SseHandler(Uri.parse('/$_kSseHandlerPath'));

     handler.connections.rest.listen((sseConnection) {
       final client = _DartDevelopmentServiceClient.fromSSEConnection(
         this,
         sseConnection,
         _vmServiceClient,
       );
       clientManager.addClient(client);
     });

     return handler.handler;
   }

   Handler _httpHandler() {
     // DDS doesn't support any HTTP requests itself, so we just forward all of
     // them to the VM service.
     final cascade = Cascade().add(proxyHandler(remoteVmServiceUri));
     return cascade.handler;
   }

   List<String> _cleanupPathSegments(Uri uri) {
     final pathSegments = <String>[];
     if (uri.pathSegments.isNotEmpty) {
       pathSegments.addAll(uri.pathSegments.where(
         // Strip out the empty string that appears at the end of path segments.
         // Empty string elements will result in an extra '/' being added to the
         // URI.
         (s) => s.isNotEmpty,
       ));
     }
     return pathSegments;
   }

   Uri _toWebSocket(Uri uri) {
     if (uri == null) {
       return null;
     }
     final pathSegments = _cleanupPathSegments(uri);
     pathSegments.add('ws');
     return uri.replace(scheme: 'ws', pathSegments: pathSegments);
   }

   Uri _toSse(Uri uri) {
     if (uri == null) {
       return null;
     }
     final pathSegments = _cleanupPathSegments(uri);
     pathSegments.add(_kSseHandlerPath);
     return uri.replace(pathSegments: pathSegments);
   }

   String _getNamespace(_DartDevelopmentServiceClient client) =>
       clientManager.clients.keyOf(client);

   bool get authCodesEnabled => _authCodesEnabled;
   final bool _authCodesEnabled;
   String _authCode;

   Uri get remoteVmServiceUri => _remoteVmServiceUri;
   Uri get remoteVmServiceWsUri => _toWebSocket(_remoteVmServiceUri);
   Uri _remoteVmServiceUri;

   Uri get uri => _uri;
   Uri get sseUri => _toSse(_uri);
   Uri get wsUri => _toWebSocket(_uri);
   Uri _uri;

   bool get isRunning => _uri != null;

   Future<void> get done => _done.future;
   Completer _done = Completer<void>();
   bool _shuttingDown = false;

   _ClientManager get clientManager => _clientManager;
   _ClientManager _clientManager;

   _ExpressionEvaluator get expressionEvaluator => _expressionEvaluator;
   _ExpressionEvaluator _expressionEvaluator;

   _IsolateManager get isolateManager => _isolateManager;
   _IsolateManager _isolateManager;

   _LoggingRepository get loggingRepository => _loggingRepository;
   _LoggingRepository _loggingRepository;

   _StreamManager get streamManager => _streamManager;
   _StreamManager _streamManager;

   static const _kSseHandlerPath = '\$debugHandler';

   json_rpc.Peer _vmServiceClient;
   WebSocketChannel _vmServiceSocket;
   HttpServer _server;
 }
	// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	part of dds;

	class _DartDevelopmentService implements DartDevelopmentService {
	_DartDevelopmentService(
	this._remoteVmServiceUri,
	this._uri,
	this._authCodesEnabled,
	) {
	_clientManager = _ClientManager(this);
	_expressionEvaluator = _ExpressionEvaluator(this);
	_isolateManager = _IsolateManager(this);
	_loggingRepository = _LoggingRepository();
	_streamManager = _StreamManager(this);
	_authCode = _authCodesEnabled ? _makeAuthToken() : '';
	}

	Future<void> startService() async {
	// TODO(bkonyi): throw if we've already shutdown.
	// Establish the connection to the VM service.
	_vmServiceSocket = WebSocketChannel.connect(remoteVmServiceWsUri);
	_vmServiceClient = _BinaryCompatiblePeer(_vmServiceSocket, _streamManager);
	// Setup the JSON RPC client with the VM service.
	unawaited(_vmServiceClient.listen().then((_) => shutdown()));

	// Setup stream event handling.
	await streamManager.listen();

	// Populate initial isolate state.
	await _isolateManager.initialize();

	// Once we have a connection to the VM service, we're ready to spawn the intermediary.
	await _startDDSServer();
	}

	Future<void> _startDDSServer() async {
	// No provided address, bind to an available port on localhost.
	// TODO(bkonyi): handle case where there's no IPv4 loopback.
	final host = uri?.host ?? InternetAddress.loopbackIPv4.host;
	final port = uri?.port ?? 0;

	// Start the DDS server.
	_server = await io.serve(
	const Pipeline()
	.addMiddleware(_authCodeMiddleware)
	.addHandler(_handlers().handler),
	host,
	port);

	final tmpUri = Uri(
	scheme: 'http',
	host: host,
	port: _server.port,
	path: '$_authCode/',
	);

	// Notify the VM service that this client is DDS and that it should close
	// and refuse connections from other clients. DDS is now acting in place of
	// the VM service.
	try {
	await _vmServiceClient.sendRequest('_yieldControlToDDS', {
	'uri': tmpUri.toString(),
	});
	} on json_rpc.RpcException catch (e) {
	await _server.close(force: true);
	// _yieldControlToDDS fails if DDS is not the only VM service client.
	throw DartDevelopmentServiceException._(e.data['details']);
	}

	_uri = tmpUri;
	}

	/// Stop accepting requests after gracefully handling existing requests.
	Future<void> shutdown() async {
	if (_done.isCompleted \|\| _shuttingDown) {
	// Already shutdown.
	return;
	}
	_shuttingDown = true;
	// Don't accept anymore HTTP requests.
	await _server?.close();

	// Close connections to clients.
	await clientManager.shutdown();

	// Close connection to VM service.
	await _vmServiceSocket.sink.close();

	_done.complete();
	}

	/// Generates a base64 authentication code that must be passed as the first
	/// part of the request path. Used to prevent random connections from clients
	/// watching the common service ports.
	static String _makeAuthToken() {
	final kTokenByteSize = 8;
	final bytes = Uint8List(kTokenByteSize);
	final random = Random.secure();
	for (int i = 0; i < kTokenByteSize; i++) {
	bytes[i] = random.nextInt(256);
	}
	return base64Url.encode(bytes);
	}

	/// Shelf middleware to verify authentication tokens before processing a
	/// request.
	///
	/// If authentication codes are enabled, a 403 response is returned if the
	/// authentication code is not the first element of the request's path.
	/// Otherwise, the request is forwarded to the first handler.
	Handler _authCodeMiddleware(Handler innerHandler) => (Request request) {
	if (_authCodesEnabled) {
	final forbidden =
	Response.forbidden('missing or invalid authentication code');
	final pathSegments = request.url.pathSegments;
	if (pathSegments.isEmpty) {
	return forbidden;
	}
	final authToken = pathSegments[0];
	if (authToken != _authCode) {
	return forbidden;
	}
	// Creates a new request with the authentication code stripped from
	// the request URI. This method doesn't behave as you might expect.
	// Calling request.change(path: authToken) has the effect of changing
	// the request's handler path from '/' to '/$authToken/' while also
	// changing the request's url from '$authToken/restofpath/' to
	// 'restofpath/'. The handler path is only used by shelf, so this
	// operation has the effect of stripping the authentication code from
	// the request.
	request = request.change(path: authToken);
	}
	return innerHandler(request);
	};

	// Attempt to upgrade HTTP requests to a websocket before processing them as
	// standard HTTP requests. The websocket handler will fail quickly if the
	// request doesn't appear to be a websocket upgrade request.
	Cascade _handlers() {
	return Cascade()
	.add(_webSocketHandler())
	.add(_sseHandler())
	.add(_httpHandler());
	}

	Handler _webSocketHandler() => webSocketHandler((WebSocketChannel ws) {
	final client = _DartDevelopmentServiceClient.fromWebSocket(
	this,
	ws,
	_vmServiceClient,
	);
	clientManager.addClient(client);
	});

	Handler _sseHandler() {
	final handler = authCodesEnabled
	? SseHandler(Uri.parse('/$_authCode/$_kSseHandlerPath'))
	: SseHandler(Uri.parse('/$_kSseHandlerPath'));

	handler.connections.rest.listen((sseConnection) {
	final client = _DartDevelopmentServiceClient.fromSSEConnection(
	this,
	sseConnection,
	_vmServiceClient,
	);
	clientManager.addClient(client);
	});

	return handler.handler;
	}

	Handler _httpHandler() {
	// DDS doesn't support any HTTP requests itself, so we just forward all of
	// them to the VM service.
	final cascade = Cascade().add(proxyHandler(remoteVmServiceUri));
	return cascade.handler;
	}

	List<String> _cleanupPathSegments(Uri uri) {
	final pathSegments = <String>[];
	if (uri.pathSegments.isNotEmpty) {
	pathSegments.addAll(uri.pathSegments.where(
	// Strip out the empty string that appears at the end of path segments.
	// Empty string elements will result in an extra '/' being added to the
	// URI.
	(s) => s.isNotEmpty,
	));
	}
	return pathSegments;
	}

	Uri _toWebSocket(Uri uri) {
	if (uri == null) {
	return null;
	}
	final pathSegments = _cleanupPathSegments(uri);
	pathSegments.add('ws');
	return uri.replace(scheme: 'ws', pathSegments: pathSegments);
	}

	Uri _toSse(Uri uri) {
	if (uri == null) {
	return null;
	}
	final pathSegments = _cleanupPathSegments(uri);
	pathSegments.add(_kSseHandlerPath);
	return uri.replace(pathSegments: pathSegments);
	}

	String _getNamespace(_DartDevelopmentServiceClient client) =>
	clientManager.clients.keyOf(client);

	bool get authCodesEnabled => _authCodesEnabled;
	final bool _authCodesEnabled;
	String _authCode;

	Uri get remoteVmServiceUri => _remoteVmServiceUri;
	Uri get remoteVmServiceWsUri => _toWebSocket(_remoteVmServiceUri);
	Uri _remoteVmServiceUri;

	Uri get uri => _uri;
	Uri get sseUri => _toSse(_uri);
	Uri get wsUri => _toWebSocket(_uri);
	Uri _uri;

	bool get isRunning => _uri != null;

	Future<void> get done => _done.future;
	Completer _done = Completer<void>();
	bool _shuttingDown = false;

	_ClientManager get clientManager => _clientManager;
	_ClientManager _clientManager;

	_ExpressionEvaluator get expressionEvaluator => _expressionEvaluator;
	_ExpressionEvaluator _expressionEvaluator;

	_IsolateManager get isolateManager => _isolateManager;
	_IsolateManager _isolateManager;

	_LoggingRepository get loggingRepository => _loggingRepository;
	_LoggingRepository _loggingRepository;

	_StreamManager get streamManager => _streamManager;
	_StreamManager _streamManager;

	static const _kSseHandlerPath = '\$debugHandler';

	json_rpc.Peer _vmServiceClient;
	WebSocketChannel _vmServiceSocket;
	HttpServer _server;
	}