rosbridge_websocket.py

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#!/usr/bin/env python
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import rospy
import json

from rosauth.srv import Authentication

from signal import signal, SIGINT, SIG_DFL
from functools import partial

from tornado.ioloop import IOLoop
from tornado.web import Application
from tornado.websocket import WebSocketHandler

from rosbridge_library.rosbridge_protocol import RosbridgeProtocol

import sys

# Global ID seed for clients
client_id_seed = 0
clients_connected = 0
# if authentication should be used
authenticate = False

class RosbridgeWebSocket(WebSocketHandler):

    def open(self):
        global client_id_seed, clients_connected, authenticate
        try:
            self.protocol = RosbridgeProtocol(client_id_seed)
            self.protocol.outgoing = self.send_message
            self.authenticated = False
            client_id_seed = client_id_seed + 1
            clients_connected = clients_connected + 1
        except Exception as exc:
            rospy.logerr("Unable to accept incoming connection.  Reason: %s", str(exc))
        rospy.loginfo("Client connected.  %d clients total.", clients_connected)
        if authenticate:
            rospy.loginfo("Awaiting proper authentication...")

    def on_message(self, message):
        global authenticate
        # check if we need to authenticate
        if authenticate and not self.authenticated:
            try:
                msg = json.loads(message)
                if msg['op'] == 'auth':
                    # check the authorization information
                    auth_srv = rospy.ServiceProxy('authenticate', Authentication)
                    resp = auth_srv(msg['mac'], msg['client'], msg['dest'], 
                                                  msg['rand'], rospy.Time(msg['t']), msg['level'], 
                                                  rospy.Time(msg['end']))
                    self.authenticated = resp.authenticated
                    if self.authenticated:
                        rospy.loginfo("Client %d has authenticated.", self.protocol.client_id)
                        return
                # if we are here, no valid authentication was given
                rospy.logwarn("Client %d did not authenticate. Closing connection.", 
                              self.protocol.client_id)
                self.close()
            except:
                # proper error will be handled in the protocol class
                self.protocol.incoming(message)
        else:
            # no authentication required
            self.protocol.incoming(message)

    def on_close(self):
        global clients_connected
        clients_connected = clients_connected - 1
        self.protocol.finish()
        rospy.loginfo("Client disconnected. %d clients total.", clients_connected)

    def send_message(self, message):
        IOLoop.instance().add_callback(partial(self.write_message, message))

if __name__ == "__main__":
    rospy.init_node("rosbridge_websocket")
    signal(SIGINT, SIG_DFL)

    # SSL options
    certfile = rospy.get_param('~certfile', None)
    keyfile = rospy.get_param('~keyfile', None)
    # if authentication should be used
    authenticate = rospy.get_param('~authenticate', False)
    port = rospy.get_param('~port', 9090)
    address = rospy.get_param('~address', "")

    if "--port" in sys.argv:
        idx = sys.argv.index("--port")+1
        if idx < len(sys.argv):
            port = int(sys.argv[idx])
        else:
            print "--port argument provided without a value."
            sys.exit(-1)

    application = Application([(r"/", RosbridgeWebSocket), (r"", RosbridgeWebSocket)])
    if certfile is not None and keyfile is not None:
        application.listen(port, address, ssl_options={ "certfile": certfile, "keyfile": keyfile})
    else:
        application.listen(port, address)
    rospy.loginfo("Rosbridge WebSocket server started on port %d", port)

    IOLoop.instance().start()