File: tulipserver.py

package info (click to toggle)
python-ws4py 0.4.2%2Bdfsg1-5
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 688 kB
  • sloc: python: 4,500; makefile: 140; javascript: 96
file content (229 lines) | stat: -rw-r--r-- 8,107 bytes parent folder | download | duplicates (3)
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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
# -*- coding: utf-8 -*-
import base64
from hashlib import sha1
from email.parser import BytesHeaderParser
import io

import asyncio

try:                                                     # pragma: no cover
    asyncio_ensure_future = asyncio.ensure_future        # Python >= 3.5
except AttributeError:                                   # pragma: no cover
    asyncio_ensure_future = getattr(asyncio, 'async')    # Python < 3.5

from ws4py import WS_KEY, WS_VERSION
from ws4py.exc import HandshakeError
from ws4py.websocket import WebSocket

LF = b'\n'
CRLF = b'\r\n'
SPACE = b' '
EMPTY = b''

__all__ = ['WebSocketProtocol']

class WebSocketProtocol(asyncio.StreamReaderProtocol):
    def __init__(self, handler_cls):
        asyncio.StreamReaderProtocol.__init__(self, asyncio.StreamReader(),
                                              self._pseudo_connected)
        self.ws = handler_cls(self)

    def _pseudo_connected(self, reader, writer):
        pass
        
    def connection_made(self, transport):
        """
        A peer is now connected and we receive an instance
        of the underlying :class:`asyncio.Transport`.

        We :class:`asyncio.StreamReader` is created
        and the transport is associated before the
        initial HTTP handshake is undertaken.
        """
        #self.transport = transport
        #self.stream = asyncio.StreamReader()
        #self.stream.set_transport(transport)
        asyncio.StreamReaderProtocol.connection_made(self, transport)
        # Let make it concurrent for others to tag along
        f = asyncio.asyncio_ensure_future(self.handle_initial_handshake())
        f.add_done_callback(self.terminated)

    @property
    def writer(self):
        return self._stream_writer
        
    @property
    def reader(self):
        return self._stream_reader
        
    def terminated(self, f):
        if f.done() and not f.cancelled():
            ex = f.exception()
            if ex:
                response = [b'HTTP/1.0 400 Bad Request']
                response.append(b'Content-Length: 0')
                response.append(b'Connection: close')
                response.append(b'')
                response.append(b'')
                self.writer.write(CRLF.join(response))
                self.ws.close_connection()

    def close(self):
        """
        Initiate the websocket closing handshake
        which will eventuall lead to the underlying
        transport.
        """
        self.ws.close()
        
    def timeout(self):
        self.ws.close_connection()
        if self.ws.started:
            self.ws.closed(1002, "Peer connection timed-out")
        
    def connection_lost(self, exc):
        """
        The peer connection is now, the closing
        handshake won't work so let's not even try.
        However let's make the websocket handler
        be aware of it by calling its `closed`
        method.
        """
        if exc is not None:
            self.ws.close_connection()
            if self.ws.started:
                self.ws.closed(1002, "Peer connection was lost")
            
    @asyncio.coroutine
    def handle_initial_handshake(self):
        """
        Performs the HTTP handshake described in :rfc:`6455`. Note that
        this implementation is really basic and it is strongly advised
        against using it in production. It would probably break for
        most clients. If you want a better support for HTTP, please
        use a more reliable HTTP server implemented using asyncio.
        """
        request_line = yield from self.next_line()
        method, uri, req_protocol = request_line.strip().split(SPACE, 2)
        
        # GET required
        if method.upper() != b'GET':
            raise HandshakeError('HTTP method must be a GET')
        
        headers = yield from self.read_headers()
        if req_protocol == b'HTTP/1.1' and 'Host' not in headers:
            raise ValueError("Missing host header")
        
        for key, expected_value in [('Upgrade', 'websocket'),
                                     ('Connection', 'upgrade')]:
            actual_value = headers.get(key, '').lower()
            if not actual_value:
                raise HandshakeError('Header %s is not defined' % str(key))
            if expected_value not in actual_value:
                raise HandshakeError('Illegal value for header %s: %s' %
                                     (key, actual_value))

        response_headers = {}

        ws_version = WS_VERSION
        version = headers.get('Sec-WebSocket-Version')
        supported_versions = ', '.join([str(v) for v in ws_version])
        version_is_valid = False
        if version:
            try: version = int(version)
            except: pass
            else: version_is_valid = version in ws_version

        if not version_is_valid:
            response_headers['Sec-WebSocket-Version'] = supported_versions
            raise HandshakeError('Unhandled or missing WebSocket version')

        key = headers.get('Sec-WebSocket-Key')
        if key:
            ws_key = base64.b64decode(key.encode('utf-8'))
            if len(ws_key) != 16:
                raise HandshakeError("WebSocket key's length is invalid")

        protocols = []
        ws_protocols = []
        subprotocols = headers.get('Sec-WebSocket-Protocol')
        if subprotocols:
            for s in subprotocols.split(','):
                s = s.strip()
                if s in protocols:
                    ws_protocols.append(s)

        exts = []
        ws_extensions = []
        extensions = headers.get('Sec-WebSocket-Extensions')
        if extensions:
            for ext in extensions.split(','):
                ext = ext.strip()
                if ext in exts:
                    ws_extensions.append(ext)

        self.ws.protocols = ws_protocols
        self.ws.extensions = ws_extensions
        self.ws.headers = headers
                    
        response = [req_protocol + b' 101 Switching Protocols']
        response.append(b'Upgrade: websocket')
        response.append(b'Content-Type: text/plain')
        response.append(b'Content-Length: 0')
        response.append(b'Connection: Upgrade')
        response.append(b'Sec-WebSocket-Version:' + bytes(str(version), 'utf-8'))
        response.append(b'Sec-WebSocket-Accept:' + base64.b64encode(sha1(key.encode('utf-8') + WS_KEY).digest()))
        if ws_protocols:
            response.append(b'Sec-WebSocket-Protocol:' + b', '.join(ws_protocols))
        if ws_extensions:
            response.append(b'Sec-WebSocket-Extensions:' + b','.join(ws_extensions))
        response.append(b'')
        response.append(b'')
        self.writer.write(CRLF.join(response))
        yield from self.handle_websocket()

    @asyncio.coroutine
    def handle_websocket(self):
        """
        Starts the websocket process until the
        exchange is completed and terminated.
        """
        yield from self.ws.run()
        
    @asyncio.coroutine
    def read_headers(self):
        """
        Read all HTTP headers from the HTTP request
        and returns a dictionary of them.
        """
        headers = b''
        while True:
            line = yield from self.next_line()
            headers += line
            if line == CRLF:
                break
        return BytesHeaderParser().parsebytes(headers)
        
    @asyncio.coroutine
    def next_line(self):
        """
        Reads data until \r\n is met and then return all read
        bytes. 
        """
        line = yield from self.reader.readline()
        if not line.endswith(CRLF):
            raise ValueError("Missing mandatory trailing CRLF")
        return line
        
if __name__ == '__main__':
    from ws4py.async_websocket import EchoWebSocket
    
    loop = asyncio.get_event_loop()

    def start_server():
        proto_factory = lambda: WebSocketProtocol(EchoWebSocket)
        return loop.create_server(proto_factory, '', 9007)

    s = loop.run_until_complete(start_server())
    print('serving on', s.sockets[0].getsockname())
    loop.run_forever()