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
|
# Copyright 2012, 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.
"""Common functions and exceptions used by WebSocket opening handshake
processors.
"""
from mod_pywebsocket import common
from mod_pywebsocket import http_header_util
class AbortedByUserException(Exception):
"""Exception for aborting a connection intentionally.
If this exception is raised in do_extra_handshake handler, the connection
will be abandoned. No other WebSocket or HTTP(S) handler will be invoked.
If this exception is raised in transfer_data_handler, the connection will
be closed without closing handshake. No other WebSocket or HTTP(S) handler
will be invoked.
"""
pass
class HandshakeException(Exception):
"""This exception will be raised when an error occurred while processing
WebSocket initial handshake.
"""
def __init__(self, name, status=None):
super(HandshakeException, self).__init__(name)
self.status = status
class VersionException(Exception):
"""This exception will be raised when a version of client request does not
match with version the server supports.
"""
def __init__(self, name, supported_versions=''):
"""Construct an instance.
Args:
supported_version: a str object to show supported hybi versions.
(e.g. '8, 13')
"""
super(VersionException, self).__init__(name)
self.supported_versions = supported_versions
def get_default_port(is_secure):
if is_secure:
return common.DEFAULT_WEB_SOCKET_SECURE_PORT
else:
return common.DEFAULT_WEB_SOCKET_PORT
def validate_subprotocol(subprotocol):
"""Validate a value in the Sec-WebSocket-Protocol field.
See the Section 4.1., 4.2.2., and 4.3. of RFC 6455.
"""
if not subprotocol:
raise HandshakeException('Invalid subprotocol name: empty')
# Parameter should be encoded HTTP token.
state = http_header_util.ParsingState(subprotocol)
token = http_header_util.consume_token(state)
rest = http_header_util.peek(state)
# If |rest| is not None, |subprotocol| is not one token or invalid. If
# |rest| is None, |token| must not be None because |subprotocol| is
# concatenation of |token| and |rest| and is not None.
if rest is not None:
raise HandshakeException('Invalid non-token string in subprotocol '
'name: %r' % rest)
def parse_host_header(request):
fields = request.headers_in[common.HOST_HEADER].split(':', 1)
if len(fields) == 1:
return fields[0], get_default_port(request.is_https())
try:
return fields[0], int(fields[1])
except ValueError, e:
raise HandshakeException('Invalid port number format: %r' % e)
def format_header(name, value):
return '%s: %s\r\n' % (name, value)
def get_mandatory_header(request, key):
value = request.headers_in.get(key)
if value is None:
raise HandshakeException('Header %s is not defined' % key)
return value
def validate_mandatory_header(request, key, expected_value, fail_status=None):
value = get_mandatory_header(request, key)
if value.lower() != expected_value.lower():
raise HandshakeException(
'Expected %r for header %s but found %r (case-insensitive)' %
(expected_value, key, value), status=fail_status)
def check_request_line(request):
# 5.1 1. The three character UTF-8 string "GET".
# 5.1 2. A UTF-8-encoded U+0020 SPACE character (0x20 byte).
if request.method != 'GET':
raise HandshakeException('Method is not GET: %r' % request.method)
if request.protocol != 'HTTP/1.1':
raise HandshakeException('Version is not HTTP/1.1: %r' %
request.protocol)
def parse_token_list(data):
"""Parses a header value which follows 1#token and returns parsed elements
as a list of strings.
Leading LWSes must be trimmed.
"""
state = http_header_util.ParsingState(data)
token_list = []
while True:
token = http_header_util.consume_token(state)
if token is not None:
token_list.append(token)
http_header_util.consume_lwses(state)
if http_header_util.peek(state) is None:
break
if not http_header_util.consume_string(state, ','):
raise HandshakeException(
'Expected a comma but found %r' % http_header_util.peek(state))
http_header_util.consume_lwses(state)
if len(token_list) == 0:
raise HandshakeException('No valid token found')
return token_list
# vi:sts=4 sw=4 et
|