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
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
# Copyright 2009, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""Web Socket handshaking.
Note: request.connection.write/read are used in this module, even though
mod_python document says that they should be used only in connection handlers.
Unfortunately, we have no other options. For example, request.write/read are
not suitable because they don't allow direct raw bytes writing/reading.
"""
import re
_DEFAULT_WEB_SOCKET_PORT = 80
_DEFAULT_WEB_SOCKET_SECURE_PORT = 443
_WEB_SOCKET_SCHEME = 'ws'
_WEB_SOCKET_SECURE_SCHEME = 'wss'
_METHOD_LINE = re.compile(r'^GET ([^ ]+) HTTP/1.1\r\n$')
_MANDATORY_HEADERS = [
# key, expected value or None
['Upgrade', 'WebSocket'],
['Connection', 'Upgrade'],
['Host', None],
['Origin', None],
]
def _default_port(is_secure):
if is_secure:
return _DEFAULT_WEB_SOCKET_SECURE_PORT
else:
return _DEFAULT_WEB_SOCKET_PORT
class HandshakeError(Exception):
"""Exception in Web Socket Handshake."""
pass
def _validate_protocol(protocol):
"""Validate WebSocket-Protocol string."""
if not protocol:
raise HandshakeError('Invalid WebSocket-Protocol: empty')
for c in protocol:
if not 0x21 <= ord(c) <= 0x7e:
raise HandshakeError('Illegal character in protocol: %r' % c)
class Handshaker(object):
"""This class performs Web Socket handshake."""
def __init__(self, request, dispatcher):
"""Construct an instance.
Args:
request: mod_python request.
dispatcher: Dispatcher (dispatch.Dispatcher).
Handshaker will add attributes such as ws_resource in performing
handshake.
"""
self._request = request
self._dispatcher = dispatcher
def do_handshake(self):
"""Perform Web Socket Handshake."""
self._check_header_lines()
self._set_resource()
self._set_origin()
self._set_location()
self._set_protocol()
self._dispatcher.do_extra_handshake(self._request)
self._send_handshake()
def _set_resource(self):
self._request.ws_resource = self._request.uri
def _set_origin(self):
self._request.ws_origin = self._request.headers_in['Origin']
def _set_location(self):
location_parts = []
if self._request.is_https():
location_parts.append(_WEB_SOCKET_SECURE_SCHEME)
else:
location_parts.append(_WEB_SOCKET_SCHEME)
location_parts.append('://')
host, port = self._parse_host_header()
connection_port = self._request.connection.local_addr[1]
if port != connection_port:
raise HandshakeError('Header/connection port mismatch: %d/%d' %
(port, connection_port))
location_parts.append(host)
if (port != _default_port(self._request.is_https())):
location_parts.append(':')
location_parts.append(str(port))
location_parts.append(self._request.uri)
self._request.ws_location = ''.join(location_parts)
def _parse_host_header(self):
fields = self._request.headers_in['Host'].split(':', 1)
if len(fields) == 1:
return fields[0], _default_port(self._request.is_https())
try:
return fields[0], int(fields[1])
except ValueError, e:
raise HandshakeError('Invalid port number format: %r' % e)
def _set_protocol(self):
protocol = self._request.headers_in.get('WebSocket-Protocol')
if protocol is not None:
_validate_protocol(protocol)
self._request.ws_protocol = protocol
def _send_handshake(self):
self._request.connection.write(
'HTTP/1.1 101 Web Socket Protocol Handshake\r\n')
self._request.connection.write('Upgrade: WebSocket\r\n')
self._request.connection.write('Connection: Upgrade\r\n')
self._request.connection.write('WebSocket-Origin: ')
self._request.connection.write(self._request.ws_origin)
self._request.connection.write('\r\n')
self._request.connection.write('WebSocket-Location: ')
self._request.connection.write(self._request.ws_location)
self._request.connection.write('\r\n')
if self._request.ws_protocol:
self._request.connection.write('WebSocket-Protocol: ')
self._request.connection.write(self._request.ws_protocol)
self._request.connection.write('\r\n')
self._request.connection.write('\r\n')
def _check_header_lines(self):
for key, expected_value in _MANDATORY_HEADERS:
actual_value = self._request.headers_in.get(key)
if not actual_value:
raise HandshakeError('Header %s is not defined' % key)
if expected_value:
if actual_value != expected_value:
raise HandshakeError('Illegal value for header %s: %s' %
(key, actual_value))
# vi:sts=4 sw=4 et
|
