testing/mochitest/pywebsocket/mod_pywebsocket/_stream_base.py

branch
TOR_BUG_9701
changeset 15
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1 # Copyright 2011, Google Inc.
2 # All rights reserved.
3 #
4 # Redistribution and use in source and binary forms, with or without
5 # modification, are permitted provided that the following conditions are
6 # met:
7 #
8 # * Redistributions of source code must retain the above copyright
9 # notice, this list of conditions and the following disclaimer.
10 # * Redistributions in binary form must reproduce the above
11 # copyright notice, this list of conditions and the following disclaimer
12 # in the documentation and/or other materials provided with the
13 # distribution.
14 # * Neither the name of Google Inc. nor the names of its
15 # contributors may be used to endorse or promote products derived from
16 # this software without specific prior written permission.
17 #
18 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30
31 """Base stream class.
32 """
33
34
35 # Note: request.connection.write/read are used in this module, even though
36 # mod_python document says that they should be used only in connection
37 # handlers. Unfortunately, we have no other options. For example,
38 # request.write/read are not suitable because they don't allow direct raw bytes
39 # writing/reading.
40
41
42 from mod_pywebsocket import util
43
44
45 # Exceptions
46
47
48 class ConnectionTerminatedException(Exception):
49 """This exception will be raised when a connection is terminated
50 unexpectedly.
51 """
52
53 pass
54
55
56 class InvalidFrameException(ConnectionTerminatedException):
57 """This exception will be raised when we received an invalid frame we
58 cannot parse.
59 """
60
61 pass
62
63
64 class BadOperationException(Exception):
65 """This exception will be raised when send_message() is called on
66 server-terminated connection or receive_message() is called on
67 client-terminated connection.
68 """
69
70 pass
71
72
73 class UnsupportedFrameException(Exception):
74 """This exception will be raised when we receive a frame with flag, opcode
75 we cannot handle. Handlers can just catch and ignore this exception and
76 call receive_message() again to continue processing the next frame.
77 """
78
79 pass
80
81
82 class InvalidUTF8Exception(Exception):
83 """This exception will be raised when we receive a text frame which
84 contains invalid UTF-8 strings.
85 """
86
87 pass
88
89
90 class StreamBase(object):
91 """Base stream class."""
92
93 def __init__(self, request):
94 """Construct an instance.
95
96 Args:
97 request: mod_python request.
98 """
99
100 self._logger = util.get_class_logger(self)
101
102 self._request = request
103
104 def _read(self, length):
105 """Reads length bytes from connection. In case we catch any exception,
106 prepends remote address to the exception message and raise again.
107
108 Raises:
109 ConnectionTerminatedException: when read returns empty string.
110 """
111
112 bytes = self._request.connection.read(length)
113 if not bytes:
114 raise ConnectionTerminatedException(
115 'Receiving %d byte failed. Peer (%r) closed connection' %
116 (length, (self._request.connection.remote_addr,)))
117 return bytes
118
119 def _write(self, bytes):
120 """Writes given bytes to connection. In case we catch any exception,
121 prepends remote address to the exception message and raise again.
122 """
123
124 try:
125 self._request.connection.write(bytes)
126 except Exception, e:
127 util.prepend_message_to_exception(
128 'Failed to send message to %r: ' %
129 (self._request.connection.remote_addr,),
130 e)
131 raise
132
133 def receive_bytes(self, length):
134 """Receives multiple bytes. Retries read when we couldn't receive the
135 specified amount.
136
137 Raises:
138 ConnectionTerminatedException: when read returns empty string.
139 """
140
141 bytes = []
142 while length > 0:
143 new_bytes = self._read(length)
144 bytes.append(new_bytes)
145 length -= len(new_bytes)
146 return ''.join(bytes)
147
148 def _read_until(self, delim_char):
149 """Reads bytes until we encounter delim_char. The result will not
150 contain delim_char.
151
152 Raises:
153 ConnectionTerminatedException: when read returns empty string.
154 """
155
156 bytes = []
157 while True:
158 ch = self._read(1)
159 if ch == delim_char:
160 break
161 bytes.append(ch)
162 return ''.join(bytes)
163
164
165 # vi:sts=4 sw=4 et

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