1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
# Copyright (c) 2016 Weitian LI <liweitianux@live.com>
# MIT license
"""
Communicate with the "fg21sim" simulation program through the Web UI using
the WebSocket_ protocol, which provides full-duplex communication channels
over a single TCP connection.
.. _WebSocket: https://en.wikipedia.org/wiki/WebSocket
References
----------
- Tornado WebSocket:
http://www.tornadoweb.org/en/stable/websocket.html
- Can I Use: WebSocket:
http://caniuse.com/#feat=websockets
"""
from urllib.parse import urlparse
import logging
import tornado.websocket
logger = logging.getLogger(__name__)
class FG21simWSHandler(tornado.websocket.WebSocketHandler):
"""
WebSocket for bi-directional communication between the Web UI and
the server, which can deal with the configurations and execute the
simulation task.
Generally, WebSocket send and receive data as *string*. Therefore,
the more complex data are stringified as JSON string before sending,
which will be parsed after receive.
Each message (as a JSON object or Python dictionary) has a ``type``
field which will be used to determine the following action to take.
Attributes
----------
name : str
Name to distinguish this WebSocket handle.
from_localhost : bool
Set to ``True`` if the access is from the localhost,
otherwise ``False``.
"""
name = "fg21sim"
from_localhost = None
def open(self):
"""Invoked when a new WebSocket is opened by the client."""
logger.info("WebSocket: %s: opened" % self.name)
def on_message(self, message):
"""Handle incoming messages."""
logger.info("WebSocket: %s: received: %s" % (self.name, message))
msg_back = message[::-1]
logger.info("WebSocket: %s: sent: %s" % (self.name, msg_back))
self.write_message(msg_back)
def on_close(self):
"""Invoked when a new WebSocket is closed by the client."""
if hasattr(self, "close_code"):
code = self.close_code
if hasattr(self, "close_reason"):
reason = self.close_reason
logger.info("WebSocket: {0}: closed by client: {1}, {2}".format(
self.name, code, reason))
def check_origin(self, origin):
"""Check the origin of the WebSocket access.
Attributes
----------
from_localhost : bool
Set to ``True`` if the access is from the localhost,
otherwise ``False``.
NOTE
----
Currently, only allow access from the ``localhost``
(i.e., 127.0.0.1) and local LAN.
"""
logger.info("WebSocket: {0}: access origin: {1}".format(
self.name, origin))
# NOTE: `urlparse`: `scheme://netloc/path;parameters?query#fragment`
netloc = urlparse(origin).netloc
# NOTE: `netloc` example: `user:pass@example.com:8080`
host = netloc.split("@")[-1].split(":")[0]
if host in ["localhost", "127.0.0.1"]:
self.from_localhost = True
logger.info("WebSocket: %s: access from localhost" % self.name)
return True
# XXX/TODO: check whether from the local LAN ??
return False
|
