|
|
"""Tornado handlers for WebSocket <-> ZMQ sockets."""
|
|
|
|
|
|
# Copyright (c) IPython Development Team.
|
|
|
# Distributed under the terms of the Modified BSD License.
|
|
|
|
|
|
import json
|
|
|
import struct
|
|
|
|
|
|
try:
|
|
|
from urllib.parse import urlparse # Py 3
|
|
|
except ImportError:
|
|
|
from urlparse import urlparse # Py 2
|
|
|
|
|
|
try:
|
|
|
from http.cookies import SimpleCookie # Py 3
|
|
|
except ImportError:
|
|
|
from Cookie import SimpleCookie # Py 2
|
|
|
import logging
|
|
|
|
|
|
import tornado
|
|
|
from tornado import ioloop
|
|
|
from tornado import web
|
|
|
from tornado import websocket
|
|
|
|
|
|
from IPython.kernel.zmq.session import Session
|
|
|
from IPython.utils.jsonutil import date_default, extract_dates
|
|
|
from IPython.utils.py3compat import PY3, cast_unicode
|
|
|
|
|
|
from .handlers import IPythonHandler
|
|
|
|
|
|
|
|
|
def serialize_binary_message(msg):
|
|
|
"""serialize a message as a binary blob
|
|
|
|
|
|
Header:
|
|
|
|
|
|
4 bytes: number of msg parts (nbufs) as 32b int
|
|
|
4 * nbufs bytes: offset for each buffer as integer as 32b int
|
|
|
|
|
|
Offsets are from the start of the buffer, including the header.
|
|
|
|
|
|
Returns
|
|
|
-------
|
|
|
|
|
|
The message serialized to bytes.
|
|
|
|
|
|
"""
|
|
|
# don't modify msg or buffer list in-place
|
|
|
msg = msg.copy()
|
|
|
buffers = list(msg.pop('buffers'))
|
|
|
bmsg = json.dumps(msg, default=date_default).encode('utf8')
|
|
|
buffers.insert(0, bmsg)
|
|
|
nbufs = len(buffers)
|
|
|
offsets = [4 * (nbufs + 1)]
|
|
|
for buf in buffers[:-1]:
|
|
|
offsets.append(offsets[-1] + len(buf))
|
|
|
offsets_buf = struct.pack('!' + 'I' * (nbufs + 1), nbufs, *offsets)
|
|
|
buffers.insert(0, offsets_buf)
|
|
|
return b''.join(buffers)
|
|
|
|
|
|
|
|
|
def deserialize_binary_message(bmsg):
|
|
|
"""deserialize a message from a binary blog
|
|
|
|
|
|
Header:
|
|
|
|
|
|
4 bytes: number of msg parts (nbufs) as 32b int
|
|
|
4 * nbufs bytes: offset for each buffer as integer as 32b int
|
|
|
|
|
|
Offsets are from the start of the buffer, including the header.
|
|
|
|
|
|
Returns
|
|
|
-------
|
|
|
|
|
|
message dictionary
|
|
|
"""
|
|
|
nbufs = struct.unpack('!i', bmsg[:4])[0]
|
|
|
offsets = list(struct.unpack('!' + 'I' * nbufs, bmsg[4:4*(nbufs+1)]))
|
|
|
offsets.append(None)
|
|
|
bufs = []
|
|
|
for start, stop in zip(offsets[:-1], offsets[1:]):
|
|
|
bufs.append(bmsg[start:stop])
|
|
|
msg = json.loads(bufs[0].decode('utf8'))
|
|
|
msg['header'] = extract_dates(msg['header'])
|
|
|
msg['parent_header'] = extract_dates(msg['parent_header'])
|
|
|
msg['buffers'] = bufs[1:]
|
|
|
return msg
|
|
|
|
|
|
|
|
|
class ZMQStreamHandler(websocket.WebSocketHandler):
|
|
|
|
|
|
def check_origin(self, origin):
|
|
|
"""Check Origin == Host or Access-Control-Allow-Origin.
|
|
|
|
|
|
Tornado >= 4 calls this method automatically, raising 403 if it returns False.
|
|
|
We call it explicitly in `open` on Tornado < 4.
|
|
|
"""
|
|
|
if self.allow_origin == '*':
|
|
|
return True
|
|
|
|
|
|
host = self.request.headers.get("Host")
|
|
|
|
|
|
# If no header is provided, assume we can't verify origin
|
|
|
if origin is None:
|
|
|
self.log.warn("Missing Origin header, rejecting WebSocket connection.")
|
|
|
return False
|
|
|
if host is None:
|
|
|
self.log.warn("Missing Host header, rejecting WebSocket connection.")
|
|
|
return False
|
|
|
|
|
|
origin = origin.lower()
|
|
|
origin_host = urlparse(origin).netloc
|
|
|
|
|
|
# OK if origin matches host
|
|
|
if origin_host == host:
|
|
|
return True
|
|
|
|
|
|
# Check CORS headers
|
|
|
if self.allow_origin:
|
|
|
allow = self.allow_origin == origin
|
|
|
elif self.allow_origin_pat:
|
|
|
allow = bool(self.allow_origin_pat.match(origin))
|
|
|
else:
|
|
|
# No CORS headers deny the request
|
|
|
allow = False
|
|
|
if not allow:
|
|
|
self.log.warn("Blocking Cross Origin WebSocket Attempt. Origin: %s, Host: %s",
|
|
|
origin, host,
|
|
|
)
|
|
|
return allow
|
|
|
|
|
|
def clear_cookie(self, *args, **kwargs):
|
|
|
"""meaningless for websockets"""
|
|
|
pass
|
|
|
|
|
|
def _reserialize_reply(self, msg_list):
|
|
|
"""Reserialize a reply message using JSON.
|
|
|
|
|
|
This takes the msg list from the ZMQ socket, deserializes it using
|
|
|
self.session and then serializes the result using JSON. This method
|
|
|
should be used by self._on_zmq_reply to build messages that can
|
|
|
be sent back to the browser.
|
|
|
"""
|
|
|
idents, msg_list = self.session.feed_identities(msg_list)
|
|
|
msg = self.session.deserialize(msg_list)
|
|
|
if msg['buffers']:
|
|
|
buf = serialize_binary_message(msg)
|
|
|
return buf
|
|
|
else:
|
|
|
smsg = json.dumps(msg, default=date_default)
|
|
|
return cast_unicode(smsg)
|
|
|
|
|
|
def _on_zmq_reply(self, msg_list):
|
|
|
# Sometimes this gets triggered when the on_close method is scheduled in the
|
|
|
# eventloop but hasn't been called.
|
|
|
if self.stream.closed(): return
|
|
|
try:
|
|
|
msg = self._reserialize_reply(msg_list)
|
|
|
except Exception:
|
|
|
self.log.critical("Malformed message: %r" % msg_list, exc_info=True)
|
|
|
else:
|
|
|
self.write_message(msg, binary=isinstance(msg, bytes))
|
|
|
|
|
|
def allow_draft76(self):
|
|
|
"""Allow draft 76, until browsers such as Safari update to RFC 6455.
|
|
|
|
|
|
This has been disabled by default in tornado in release 2.2.0, and
|
|
|
support will be removed in later versions.
|
|
|
"""
|
|
|
return True
|
|
|
|
|
|
# ping interval for keeping websockets alive (30 seconds)
|
|
|
WS_PING_INTERVAL = 30000
|
|
|
|
|
|
class AuthenticatedZMQStreamHandler(ZMQStreamHandler, IPythonHandler):
|
|
|
ping_callback = None
|
|
|
last_ping = 0
|
|
|
last_pong = 0
|
|
|
|
|
|
@property
|
|
|
def ping_interval(self):
|
|
|
"""The interval for websocket keep-alive pings.
|
|
|
|
|
|
Set ws_ping_interval = 0 to disable pings.
|
|
|
"""
|
|
|
return self.settings.get('ws_ping_interval', WS_PING_INTERVAL)
|
|
|
|
|
|
@property
|
|
|
def ping_timeout(self):
|
|
|
"""If no ping is received in this many milliseconds,
|
|
|
close the websocket connection (VPNs, etc. can fail to cleanly close ws connections).
|
|
|
Default is max of 3 pings or 30 seconds.
|
|
|
"""
|
|
|
return self.settings.get('ws_ping_timeout',
|
|
|
max(3 * self.ping_interval, WS_PING_INTERVAL)
|
|
|
)
|
|
|
|
|
|
def set_default_headers(self):
|
|
|
"""Undo the set_default_headers in IPythonHandler
|
|
|
|
|
|
which doesn't make sense for websockets
|
|
|
"""
|
|
|
pass
|
|
|
|
|
|
def get(self, *args, **kwargs):
|
|
|
# Check to see that origin matches host directly, including ports
|
|
|
# Tornado 4 already does CORS checking
|
|
|
if tornado.version_info[0] < 4:
|
|
|
if not self.check_origin(self.get_origin()):
|
|
|
raise web.HTTPError(403)
|
|
|
|
|
|
# authenticate the request before opening the websocket
|
|
|
if self.get_current_user() is None:
|
|
|
self.log.warn("Couldn't authenticate WebSocket connection")
|
|
|
raise web.HTTPError(403)
|
|
|
|
|
|
if self.get_argument('session_id', False):
|
|
|
self.session.session = cast_unicode(self.get_argument('session_id'))
|
|
|
else:
|
|
|
self.log.warn("No session ID specified")
|
|
|
|
|
|
return super(AuthenticatedZMQStreamHandler, self).get(*args, **kwargs)
|
|
|
|
|
|
def initialize(self):
|
|
|
self.session = Session(config=self.config)
|
|
|
|
|
|
def open(self, kernel_id):
|
|
|
self.kernel_id = cast_unicode(kernel_id, 'ascii')
|
|
|
|
|
|
# start the pinging
|
|
|
if self.ping_interval > 0:
|
|
|
self.last_ping = ioloop.IOLoop.instance().time() # Remember time of last ping
|
|
|
self.last_pong = self.last_ping
|
|
|
self.ping_callback = ioloop.PeriodicCallback(self.send_ping, self.ping_interval)
|
|
|
self.ping_callback.start()
|
|
|
|
|
|
def send_ping(self):
|
|
|
"""send a ping to keep the websocket alive"""
|
|
|
if self.stream.closed() and self.ping_callback is not None:
|
|
|
self.ping_callback.stop()
|
|
|
return
|
|
|
|
|
|
# check for timeout on pong. Make sure that we really have sent a recent ping in
|
|
|
# case the machine with both server and client has been suspended since the last ping.
|
|
|
now = ioloop.IOLoop.instance().time()
|
|
|
since_last_pong = 1e3 * (now - self.last_pong)
|
|
|
since_last_ping = 1e3 * (now - self.last_ping)
|
|
|
if since_last_ping < 2*self.ping_interval and since_last_pong > self.ping_timeout:
|
|
|
self.log.warn("WebSocket ping timeout after %i ms.", since_last_pong)
|
|
|
self.close()
|
|
|
return
|
|
|
|
|
|
self.ping(b'')
|
|
|
self.last_ping = now
|
|
|
|
|
|
def on_pong(self, data):
|
|
|
self.last_pong = ioloop.IOLoop.instance().time()
|
|
|
|
