JSON-RPC over Websockets implementation.

README.rst

@@ -2,4 +2,4 @@ GNS3-server
 ===========
 
 GNS3 server manages emulators such as Dynamips, VirtualBox or Qemu/KVM.
-Clients like the GNS3 GUI controls the server using a HTTP REST API.
+Clients like the GNS3 GUI controls the server using an API over Websockets.

gns3server/handlers/jsonrpc_websocket.py

@@ -0,0 +1,148 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2013 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+JSON-RPC protocol over Websockets.
+"""
+
+import zmq
+import uuid
+import tornado.websocket
+from tornado.escape import json_decode
+from ..jsonrpc import JSONRPCParseError, JSONRPCInvalidRequest, JSONRPCMethodNotFound
+
+import logging
+log = logging.getLogger(__name__)
+
+
+class JSONRPCWebSocket(tornado.websocket.WebSocketHandler):
+    """
+    STOMP protocol over Tornado Websockets with message
+    routing to ZeroMQ dealer clients.
+
+    :param application: Tornado Application object
+    :param request: Tornado Request object
+    :param zmq_router: ZeroMQ router socket
+    """
+
+    clients = set()
+    destinations = {}
+    version = 2.0  # only JSON-RPC version 2.0 is supported
+
+    def __init__(self, application, request, zmq_router):
+        tornado.websocket.WebSocketHandler.__init__(self, application, request)
+        self._session_id = str(uuid.uuid4())
+        self.zmq_router = zmq_router
+
+    @property
+    def session_id(self):
+        """
+        Session ID uniquely representing a Websocket client
+
+        :returns: the session id
+        """
+
+        return self._session_id
+
+    @classmethod
+    def dispatch_message(cls, message):
+        """
+        Sends a message to Websocket client
+
+        :param message: message from a module (received via ZeroMQ)
+        """
+
+        # Module name that is replying
+        module = message[0].decode("utf-8")
+
+        # ZMQ responses are encoded in JSON
+        # format is a JSON array: [session ID, JSON-RPC response]
+        json_message = json_decode(message[1])
+        session_id = json_message[0]
+        jsonrpc_response = json_message[1]
+
+        log.debug("Received message from module {}: {}".format(module, json_message))
+
+        for client in cls.clients:
+            if client.session_id == session_id:
+                client.write_message(jsonrpc_response)
+
+    @classmethod
+    def register_destination(cls, destination, module):
+        """
+        Registers a destination handled by a module.
+        Used to route requests to the right module.
+
+        :param destination: destination string
+        :param module: module string
+        """
+
+        # Make sure the destination is not already registered
+        # by another module for instance
+        assert destination not in cls.destinations
+        log.info("registering {} as a destination for {}".format(destination,
+                                                                 module))
+        cls.destinations[destination] = module
+
+    def open(self):
+        """
+        Invoked when a new WebSocket is opened.
+        """
+
+        log.info("Websocket client {} connected".format(self.session_id))
+        self.clients.add(self)
+
+    def on_message(self, message):
+        """
+        Handles incoming messages.
+
+        :param message: message received over the Websocket
+        """
+
+        log.debug("Received Websocket message: {}".format(message))
+
+        try:
+            request = json_decode(message)
+            jsonrpc_version = request["jsonrpc"]
+            method = request["method"]
+            # warning: notifications cannot be sent by a client because check for an "id" here
+            request_id = request["id"]
+        except:
+            return self.write_message(JSONRPCParseError()())
+
+        if jsonrpc_version != self.version:
+            return self.write_message(JSONRPCInvalidRequest()())
+
+        if method not in self.destinations:
+            return self.write_message(JSONRPCMethodNotFound(request_id)())
+
+        module = self.destinations[method]
+        # ZMQ requests are encoded in JSON
+        # format is a JSON array: [session ID, JSON-RPC request]
+        zmq_request = [self.session_id, request]
+        # Route to the correct module
+        self.zmq_router.send_string(module, zmq.SNDMORE)
+        # Send the encoded JSON request
+        self.zmq_router.send_json(zmq_request)
+
+    def on_close(self):
+        """
+        Invoked when the WebSocket is closed.
+        """
+
+        log.info("Websocket client {} disconnected".format(self.session_id))
+        self.clients.remove(self)

gns3server/jsonrpc.py

@@ -0,0 +1,182 @@
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2013 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+JSON-RPC protocol implementation.
+http://www.jsonrpc.org/specification
+"""
+
+import json
+import uuid
+
+
+class JSONRPCObject(object):
+    """
+    Base object for JSON-RPC requests, responses,
+    notifications and errors.
+    """
+
+    def __init__(self):
+        return JSONRPCEncoder().default(self)
+
+    def __str__(self, *args, **kwargs):
+        return json.dumps(self, cls=JSONRPCEncoder)
+
+    def __call__(self):
+        return JSONRPCEncoder().default(self)
+
+
+class JSONRPCEncoder(json.JSONEncoder):
+    """
+    Creates the JSON-RPC message.
+    """
+
+    def default(self, obj):
+        """
+        Returns a Python dictionary corresponding to a JSON-RPC message.
+        """
+
+        if isinstance(obj, JSONRPCObject):
+            message = {"jsonrpc": 2.0}
+            for field in dir(obj):
+                if not field.startswith('_'):
+                    value = getattr(obj, field)
+                    message[field] = value
+            return message
+        return json.JSONEncoder.default(self, obj)
+
+
+class JSONRPCInvalidRequest(JSONRPCObject):
+    """
+    Error response for an invalid request.
+    """
+
+    def __init__(self):
+        JSONRPCObject.__init__(self)
+        self.id = None
+        self.error = {"code": -32600, "message": "Invalid Request"}
+
+
+class JSONRPCMethodNotFound(JSONRPCObject):
+    """
+    Error response for an method not found.
+
+    :param request_id: JSON-RPC identifier
+    """
+
+    def __init__(self, request_id):
+        JSONRPCObject.__init__(self)
+        self.id = request_id
+        self.error = {"code": -32601, "message": "Method not found"}
+
+
+class JSONRPCInvalidParams(JSONRPCObject):
+    """
+    Error response for invalid parameters.
+
+    :param request_id: JSON-RPC identifier
+    """
+
+    def __init__(self, request_id):
+        JSONRPCObject.__init__(self)
+        self.id = request_id
+        self.error = {"code": -32602, "message": "Invalid params"}
+
+
+class JSONRPCInternalError(JSONRPCObject):
+    """
+    Error response for an internal error.
+
+    :param request_id: JSON-RPC identifier (optional)
+    """
+
+    def __init__(self, request_id=None):
+        JSONRPCObject.__init__(self)
+        self.id = request_id
+        self.error = {"code": -32603, "message": "Internal error"}
+
+
+class JSONRPCParseError(JSONRPCObject):
+    """
+    Error response for parsing error.
+    """
+
+    def __init__(self):
+        JSONRPCObject.__init__(self)
+        self.id = None
+        self.error = {"code": -32700, "message": "Parse error"}
+
+
+class JSONRPCCustomError(JSONRPCObject):
+    """
+    Error response for an custom error.
+
+    :param code: JSON-RPC error code
+    :param message: JSON-RPC error message
+    :param request_id: JSON-RPC identifier (optional)
+    """
+
+    def __init__(self, code, message, request_id=None):
+        JSONRPCObject.__init__(self)
+        self.id = request_id
+        self.error = {"code": code, "message": message}
+
+
+class JSONRPCResponse(JSONRPCObject):
+    """
+    JSON-RPC successful response.
+
+    :param result: JSON-RPC result
+    :param request_id: JSON-RPC identifier
+    """
+
+    def __init__(self, result, request_id):
+        JSONRPCObject.__init__(self)
+        self.id = request_id
+        self.result = result
+
+
+class JSONRPCRequest(JSONRPCObject):
+    """
+    JSON-RPC request.
+
+    :param method: JSON-RPC destination method
+    :param params: JSON-RPC params for the corresponding method (optional)
+    :param request_id: JSON-RPC identifier (generated by default)
+    """
+
+    def __init__(self, method, params=None, request_id=str(uuid.uuid1())):
+        JSONRPCObject.__init__(self)
+        self.id = request_id
+        self.method = method
+        if params:
+            self.params = params
+
+
+class JSONRPCNotification(JSONRPCObject):
+    """
+    JSON-RPC notification.
+
+    :param method: JSON-RPC destination method
+    :param params: JSON-RPC params for the corresponding method (optional)
+    """
+
+    def __init__(self, method, params=None):
+        JSONRPCObject.__init__(self)
+        self.method = method
+        if params:
+            self.params = params

gns3server/main.py

@@ -19,8 +19,8 @@
 import datetime
 import sys
 import logging
-import gns3server
 import tornado.options
+import gns3server
 
 # command line options
 from tornado.options import define

gns3server/modules/base.py

@@ -19,6 +19,7 @@
 Base class (interface) for modules
 """
 
+import gns3server.jsonrpc as jsonrpc
 import multiprocessing
 import zmq
 
@@ -28,7 +29,11 @@ log = logging.getLogger(__name__)
 
 class IModule(multiprocessing.Process):
     """
-    Module interface
+    Module interface.
+
+    :param name: module name
+    :param args: arguments for the module
+    :param kwargs: named arguments for the module
     """
 
     destination = {}
@@ -47,6 +52,7 @@ class IModule(multiprocessing.Process):
         self._port = args[1]
         self._current_session = None
         self._current_destination = None
+        self._current_call_id = None
 
     def _setup(self):
         """
@@ -59,7 +65,9 @@ class IModule(multiprocessing.Process):
 
     def _create_stream(self, host=None, port=0, callback=None):
         """
-        Creates a new ZMQ stream
+        Creates a new ZMQ stream.
+
+        :returns: ZMQ stream object
         """
 
         socket = self._context.socket(zmq.DEALER)
@@ -98,27 +106,66 @@ class IModule(multiprocessing.Process):
 
     def stop(self):
         """
-        Stops the event loop
+        Stops the event loop.
         """
 
-        #zmq.eventloop.ioloop.IOLoop.instance().stop()
         self._ioloop.stop()
 
-    def send_response(self, response):
+    def send_response(self, results):
         """
-        Sends a response back to the requester
+        Sends a response back to the requester.
 
-        :param response:
+        :param results: JSON results to the ZeroMQ server
         """
 
-        # add session and destination to the response
+        jsonrpc_response = jsonrpc.JSONRPCResponse(results, self._current_call_id)()
-        response = [self._current_session, self._current_destination, response]
+
+        # add session to the response
+        response = [self._current_session, jsonrpc_response]
         log.debug("ZeroMQ client ({}) sending: {}".format(self.name, response))
         self._stream.send_json(response)
 
+    def send_param_error(self):
+        """
+        Sends a param error back to the requester.
+        """
+
+        jsonrpc_response = jsonrpc.JSONRPCInvalidParams(self._current_call_id)()
+
+        # add session to the response
+        response = [self._current_session, jsonrpc_response]
+        log.info("ZeroMQ client ({}) sending JSON-RPC param error for call id {}".format(self.name, self._current_call_id))
+        self._stream.send_json(response)
+
+    def send_internal_error(self):
+        """
+        Sends a param error back to the requester.
+        """
+
+        jsonrpc_response = jsonrpc.JSONRPCInternalError()()
+
+        # add session to the response
+        response = [self._current_session, jsonrpc_response]
+        log.critical("ZeroMQ client ({}) sending JSON-RPC internal error".format(self.name))
+        self._stream.send_json(response)
+
+    def send_custom_error(self, message, code=-3200):
+        """
+        Sends a custom error back to the requester.
+        """
+
+        jsonrpc_response = jsonrpc.JSONRPCCustomError(code, message, self._current_call_id)()
+
+        # add session to the response
+        response = [self._current_session, jsonrpc_response]
+        log.info("ZeroMQ client ({}) sending JSON-RPC custom error {} for call id {}".format(self.name,
+                                                                                             message,
+                                                                                             self._current_call_id))
+        self._stream.send_json(response)
+
     def _decode_request(self, request):
         """
-        Decodes the request to JSON
+        Decodes the request to JSON.
 
         :param request: request from ZeroMQ server
         """
@@ -126,18 +173,22 @@ class IModule(multiprocessing.Process):
         try:
             request = zmq.utils.jsonapi.loads(request[0])
         except ValueError:
-            self.send_response("ValueError")  # FIXME: explicit json error
+            self._current_session = None
+            self.send_internal_error()
             return
 
         log.debug("ZeroMQ client ({}) received: {}".format(self.name, request))
         self._current_session = request[0]
-        self._current_destination = request[1]
+        self._current_call_id = request[1].get("id")
+        destination = request[1].get("method")
+        params = request[1].get("params")
 
-        if self._current_destination not in self.destination:
+        if destination not in self.destination:
-            # FIXME: return error if destination not found!
+            self.send_internal_error()
             return
-        log.debug("Routing request to {}: {}".format(self._current_destination, request[2]))
+
-        self.destination[self._current_destination](self, request[2])
+        log.debug("Routing request to {}: {}".format(destination, request[1]))
+        self.destination[destination](self, params)
 
     def destinations(self):
         """

gns3server/server.py

@@ -31,7 +31,7 @@ import socket
 import tornado.ioloop
 import tornado.web
 import tornado.autoreload
-from .handlers.stomp_websocket import StompWebSocket
+from .handlers.jsonrpc_websocket import JSONRPCWebSocket
 from .handlers.version_handler import VersionHandler
 from .module_manager import ModuleManager
 
@@ -57,7 +57,7 @@ class Server(object):
 
     def load_modules(self):
         """
-        Loads the modules
+        Loads the modules.
         """
 
         cwd = os.path.dirname(os.path.abspath(__file__))
@@ -70,17 +70,17 @@ class Server(object):
             self._modules.append(instance)
             destinations = instance.destinations()
             for destination in destinations:
-                StompWebSocket.register_destination(destination, module.name)
+                JSONRPCWebSocket.register_destination(destination, module.name)
             instance.start()  # starts the new process
 
     def run(self):
         """
-        Starts the Tornado web server and ZeroMQ server
+        Starts the Tornado web server and ZeroMQ server.
         """
 
         router = self._create_zmq_router()
-        # Add our Stomp Websocket handler to Tornado
+        # Add our JSON-RPC Websocket handler to Tornado
-        self.handlers.extend([(r"/", StompWebSocket, dict(zmq_router=router))])
+        self.handlers.extend([(r"/", JSONRPCWebSocket, dict(zmq_router=router))])
         tornado_app = tornado.web.Application(self.handlers, debug=True)  # FIXME: debug mode!
         try:
             print("Starting server on port {}".format(self._port))
@@ -92,7 +92,7 @@ class Server(object):
 
         ioloop = tornado.ioloop.IOLoop.instance()
         stream = zmqstream.ZMQStream(router, ioloop)
-        stream.on_recv(StompWebSocket.dispatch_message)
+        stream.on_recv(JSONRPCWebSocket.dispatch_message)
         tornado.autoreload.add_reload_hook(functools.partial(self._cleanup, stop=False))
 
         def signal_handler(signum=None, frame=None):

tests/test_jsonrpc.py

@@ -0,0 +1,91 @@
+import uuid
+from tornado.testing import AsyncTestCase
+from tornado.escape import json_encode, json_decode
+from ws4py.client.tornadoclient import TornadoWebSocketClient
+import gns3server.jsonrpc as jsonrpc
+
+"""
+Tests for JSON-RPC protocol over Websockets
+"""
+
+
+class JSONRPC(AsyncTestCase):
+
+    URL = "ws://127.0.0.1:8000/"
+
+    def test_request(self):
+
+        params = {"echo": "test"}
+        request = jsonrpc.JSONRPCRequest("dynamips.echo", params)
+        AsyncWSRequest(self.URL, self.io_loop, self.stop, str(request))
+        response = self.wait()
+        json_response = json_decode(response)
+        assert json_response["jsonrpc"] == 2.0
+        assert json_response["id"] == request.id
+        assert json_response["result"] == params
+
+    def test_request_with_invalid_method(self):
+
+        message = {"echo": "test"}
+        request = jsonrpc.JSONRPCRequest("dynamips.non_existent", message)
+        AsyncWSRequest(self.URL, self.io_loop, self.stop, str(request))
+        response = self.wait()
+        json_response = json_decode(response)
+        assert json_response["error"].get("code") == -32601
+        assert json_response["id"] == request.id
+
+    def test_request_with_invalid_version(self):
+
+        request = {"jsonrpc": "1.0", "method": "dynamips.echo", "id": 1}
+        AsyncWSRequest(self.URL, self.io_loop, self.stop, json_encode(request))
+        response = self.wait()
+        json_response = json_decode(response)
+        assert json_response["id"] == None
+        assert json_response["error"].get("code") == -32600
+
+    def test_request_with_invalid_json(self):
+
+        request = "my non JSON request"
+        AsyncWSRequest(self.URL, self.io_loop, self.stop, request)
+        response = self.wait()
+        json_response = json_decode(response)
+        assert json_response["id"] == None
+        assert json_response["error"].get("code") == -32700
+
+    def test_request_with_invalid_jsonrpc_field(self):
+
+        request = {"jsonrpc": "2.0", "method_bogus": "dynamips.echo", "id": 1}
+        AsyncWSRequest(self.URL, self.io_loop, self.stop, json_encode(request))
+        response = self.wait()
+        json_response = json_decode(response)
+        assert json_response["id"] == None
+        assert json_response["error"].get("code") == -32700
+
+    def test_request_with_no_params(self):
+
+        request = jsonrpc.JSONRPCRequest("dynamips.echo")
+        AsyncWSRequest(self.URL, self.io_loop, self.stop, str(request))
+        response = self.wait()
+        json_response = json_decode(response)
+        assert json_response["id"] == request.id
+        assert json_response["error"].get("code") == -32602
+
+
+class AsyncWSRequest(TornadoWebSocketClient):
+    """
+    Very basic Websocket client for tests
+    """
+
+    def __init__(self, url, io_loop, callback, message):
+        TornadoWebSocketClient.__init__(self, url, io_loop=io_loop)
+        self._callback = callback
+        self._message = message
+        self.connect()
+
+    def opened(self):
+        self.send(self._message, binary=False)
+
+    def received_message(self, message):
+        self.close()
+        if self._callback:
+            self._callback(message.data)

tests/test_stomp.py

@@ -6,7 +6,7 @@ from gns3server.stomp import frame as stomp_frame
 from gns3server.stomp import protocol as stomp_protocol
 
 """
-Tests STOMP protocol over Websockets
+Tests for STOMP protocol over Websockets
 """
 
 
@@ -64,7 +64,7 @@ class Stomp(AsyncTestCase):
         and check for a STOMP MESSAGE with echoed message and destination.
         """
 
-        destination = "dynamips/echo"
+        destination = "dynamips.echo"
         message = {"ping": "test"}
         request = self.stomp.send(destination, json_encode(message), "application/json")
         AsyncWSRequest(self.URL, self.io_loop, self.stop, request)
@@ -109,7 +109,7 @@ class Stomp(AsyncTestCase):
 
 class AsyncWSRequest(TornadoWebSocketClient):
     """
-    Very basic Websocket client for the tests
+    Very basic Websocket client for tests
     """
 
     def __init__(self, url, io_loop, callback, message):